WO2023099776A1

WO2023099776A1 - Aerosol-generating article having an air channelling element with inner and outer air passageways

Info

Publication number: WO2023099776A1
Application number: PCT/EP2022/084304
Authority: WO
Inventors: Jerome Uthurry; Loïc DA COSTA
Original assignee: Philip Morris Products S.A.
Priority date: 2021-12-02
Filing date: 2022-12-02
Publication date: 2023-06-08

Abstract

There is provided an aerosol-generating article for producing an inhalable aerosol upon heating. The aerosol-generating article comprises a rod of aerosol-generating substrate. The aerosol-generating article comprises an air channelling element abutting the rod of aerosol-generating substrate. The air channelling element comprises a body comprising a core portion and a peripheral portion. The core portion comprises one or more inner air passageways and the peripheral portion comprises one or more outer air passageways. A total cross-sectional area of the one or more outer air passageways is greater than a total cross-sectional area of the one or more inner air passageways. The aerosol-generating article further comprises a ventilation zone, which allows fluid ingress into the outer air passageway from the exterior of the article.

Description

AEROSOL-GENERATING ARTICLE HAVING AN AIR CHANNELLING ELEMENT WITH INNER AND OUTER AIR PASSAGEWAYS

The present invention relates to an aerosol-generating article comprising an aerosolgenerating substrate and adapted to produce an inhalable aerosol upon heating. The present disclosure also relates to an aerosol-generating system comprising such an aerosol-generating article.

Aerosol-generating articles in which an aerosol-generating substrate, such as a tobaccocontaining substrate, is heated rather than combusted, are known in the art. Typically, in such heated smoking articles an aerosol is generated by the transfer of heat from a heat source to a physically separate aerosol-generating substrate or material, which may be located in contact with, within, around, or downstream of the heat source. During use of the aerosol-generating article, volatile compounds are released from the aerosol-generating substrate by heat transfer from the heat source and are entrained in air drawn through the aerosol-generating article. As the released compounds cool, they condense to form an aerosol.

A number of prior art documents disclose aerosol-generating devices for consuming aerosol-generating articles. Such devices include, for example, electrically heated aerosolgenerating devices in which an aerosol is generated by the transfer of heat from one or more electrical heater elements of the aerosol-generating device to the aerosol-generating substrate of a heated aerosol-generating article. For example, electrically heated aerosol-generating devices have been proposed that comprise an internal heater blade which is adapted to be inserted into the aerosol-generating substrate. Use of an aerosol-generating article in combination with an external heating system is also known. For example, WO 2020/115151 describes the provision of one or more heating elements arranged around the periphery of the aerosol-generating article when the aerosol-generating article is received in a cavity of the aerosol-generating device. As an alternative, inductively heatable aerosol-generating articles comprising an aerosol-generating substrate and a susceptor arranged within the aerosol-generating substrate have been proposed by WO 2015/176898.

Aerosol-generating articles in which a tobacco-containing substrate is heated rather than combusted present a number of challenges that were not encountered with conventional smoking articles. First of all, tobacco-containing substrates are typically heated to significantly lower temperatures compared with the temperatures reached by the combustion front in a conventional cigarette. This may have an impact on nicotine release from the tobacco-containing substrate and nicotine delivery to the consumer. At the same time, if the heating temperature is increased in an attempt to boost nicotine delivery, then the aerosol generated typically needs to be cooled to a greater extent and more rapidly before it reaches the consumer. However, technical solutions that were commonly used for cooling the mainstream smoke in conventional smoking articles, such as the provision of a high filtration efficiency segment at the mouth end of a cigarette, may have undesirable effects in an aerosol-generating article wherein a tobacco-containing substrate is heated rather than combusted, as they may reduce nicotine delivery. Accordingly, it would be desirable to provide novel aerosol-generating articles that can consistently ensure a quick and satisfactory aerosol delivery to the consumer.

Secondly, a need is generally felt for aerosol-generating articles that are easy to use and have improved practicality. For example, it would be desirable to provide an aerosol-generating article that can be easily inserted into a heating cavity of the aerosol-generating device, and that at the same time can be held securely within the heating cavity such that it does not slip out during use.

Therefore, it would be desirable to provide a new and improved aerosol-generating article adapted to achieve at least one of the desirable results described above. Further, it would be desirable to provide one such aerosol-generating article that can be manufactured efficiently and at high speed, preferably with a satisfactory RTD and low RTD variability from one article to another.

The present disclosure relates to an aerosol-generating article. The aerosol-generating article may comprise a rod of aerosol-generating substrate. The aerosol-generating article may comprise an air channelling element upstream or downstream of the rod of aerosol-generating substrate. The aerosol-generating article may comprise an air channelling element abutting the rod of aerosol-generating substrate. The air channelling element may comprise a body comprising a core portion and a peripheral portion. The core portion may comprise one or more inner air passageways and the peripheral portion may comprise one or more outer air passageways. A total cross-sectional area of the one or more outer air passageways may be greater than a total cross-sectional area of the one or more inner air passageways.

The present disclosure relates to an aerosol-generating article. The aerosol-generating article may comprise a rod of aerosol-generating substrate. The aerosol-generating article may comprise a downstream section extending downstream from the rod of aerosol-generating substrate. The downstream section may comprise an air channelling element. The downstream air channelling element may abut the rod of aerosol-generating substrate. The downstream air channelling element may comprise a body comprising a core portion and a peripheral portion. The core portion may comprise one or more inner air passageways and the peripheral portion may comprise one or more outer air passageways. A total cross-sectional area of the one or more outer air passageways may be greater than a total cross-sectional area of the one or more inner air passageways.

The present disclosure relates to an aerosol-generating article. The aerosol-generating article may comprise a rod of aerosol-generating substrate. The aerosol-generating article may comprise an upstream section extending upstream from the rod of aerosol-generating substrate. The upstream section may comprise an air channelling element. The upstream air channelling element may abut the rod of aerosol-generating substrate. The upstream air channelling element may comprise a body comprising a core portion and a peripheral portion. The core portion may comprise one or more inner air passageways and the peripheral portion may comprise one or more outer air passageways. A total cross-sectional area of the one or more outer air passageways may be greater than a total cross-sectional area of the one or more inner air passageways.

The total cross-sectional area of the one or more air passageways may refer to the sum of the transverse cross-sectional areas of each of the air passageways. The core portion may be a central portion of the body. The one or more inner air passageways may be one or more central air passageways. The one or more outer air passageways may refer to one or more peripheral air passageways.

The present invention relates to an aerosol-generating article. The aerosol-generating article comprises a rod of aerosol-generating substrate. The aerosol-generating article comprises an air channelling element abutting the rod of aerosol-generating substrate. The air channelling element comprises a body comprising a core portion and a peripheral portion. The core portion comprises one or more inner air passageways and the peripheral portion comprises one or more outer air passageways. A total cross-sectional area of the one or more outer air passageways is greater than a total cross-sectional area of the one or more inner air passageways.

The total cross-sectional area of the one or more air passageways may refer to the sum of the transverse cross-sectional areas of each of the air passageways. The core portion may be a central portion of the body. The one or more inner air passageways may be one or more central air passageways.

Further, the present disclosure relates to an aerosol-generating system comprising an aerosol-generating article described herein and an aerosol-generating device, wherein the aerosol-generating device comprises a heating chamber for receiving the aerosol-generating article and a heating member arranged at or about a periphery of the heating chamber. The heating member may be an external heater.

Aerosol-generating articles according to the present disclosure provide an improved configuration having a direct impact on enhancing the speed and the efficiency of aerosol generation, particularly when the aerosol-generating article is externally heated. The speed of aerosol generation refers to how quickly aerosol may be generated. This is due to providing an air channelling element with one or more outer air passageways upstream or downstream of the aerosol-generating substrate. The one or more outer air passageways of the air channelling element may encourage air flow through the peripheral portion of the aerosol-generating substrate. Upon external heating, an outer peripheral layer of the substrate may heat up first and may therefore be the first portion of the substrate to be the source of aerosol generation during the initial stages of the heating cycle of the article. By aligning the one or more outer air passageways and the resulting external air flow with such an outer peripheral portion of the substrate, any air drawn towards or from the aerosol-generating substrate may be directed towards or drawn from such an outer peripheral layer of the substrate.

An upstream air channelling element located upstream of the aerosol-generating substrate beneficially focusses air intake onto the peripheral portion of substrate, as described above, while also providing a barrier against any inadvertent exit of the substrate material debris via the upstream end of the aerosol-generating article during consumption and transportation.

A downstream air channelling element located downstream of the aerosol-generating substrate beneficially encourages the air intake to flow through the outer peripheral portion of the substrate. The downstream air channelling element further provides enhanced cooling due to the proximity of the one or more outer air passageways to the exterior or periphery of the aerosolgenerating article, thereby enabling heat transfer with the exterior of the aerosol-generating article in addition to the material of the air channelling element itself. Accordingly, the present invention encourages prompt aerosol nucleation and aerosol delivery to a user, particularly in the initial stages of the consumption of an externally heated article.

Further, the provision of an air channelling element having outer air passageways, which in total have a greater cross-sectional area than inner passageways provided in the air channelling element, ensures the directing of air to, or aerosol from, the aerosol-generating substrate while providing an auxiliary air flow via a core portion of the air channelling element. With the core portion preferably being a central portion of the air channelling element, the inner air passageway may additionally provide air flow to or from more central regions of the aerosolgenerating substrate.

Particularly when the aerosol-generating substrate is externally heated, the central portion of the substrate may take relatively longer to heat up. Therefore, aerosol may be derived from such a central portion towards the latter stages of the consumption of the article. As a result, the combination of outer and inner air passageways advantageously provides air to and from the peripheral and central regions of the substrate, thereby beneficially encompassing different stages of the heating cycle of the substrate and providing enhanced and consistent aerosoldelivery to a consumer. The greater cross-sectional area of the outer air passageways ensures that aerosol is generated consistently and promptly during the initial stages of the heating cycle where the peripheral portion of the substrate is being heated when the article is placed in an external heating chamber.

The outer air passageways of an upstream air channelling element focusses the air intake on the peripheral portion of the substrate while the outer air passageways of a downstream air channelling element encourage aerosol being drawn through and from the peripheral portion.

Additionally, the air channelling element, either upstream or downstream, may also provide a barrier preventing inadvertent exit of any particles or debris from the aerosol-generating substrate from exiting or transferring to other components of the aerosol-generating article. The outer and inner air passageways may be sized and shaped in a manner that such particles of aerosol-generating substrate may find it difficult to pass through them.

As used herein, the term “length” denotes the dimension of a component, device, or article in the longitudinal direction, from the component’s furthest upstream or distal point to the component’s furthest downstream or proximal point.

As used herein, the term “longitudinal” refers to the direction corresponding to the main longitudinal axis of a component, device, or article, which extends between the opposing upstream and downstream ends of the component, device, or article. The term "transverse" is used to describe a direction perpendicular to the longitudinal direction. As used herein, the term "cross-section" (in other words, “transverse cross-section”) may be used to describe the crosssection of a component, device, or article perpendicular to the longitudinal direction.

As used herein, the terms “upstream” and “downstream” describe the relative positions of elements, or portions of elements, of the component, device, or article in relation to the direction in which the air may be drawn through the component, device, or article during use. During use or consumption, air may be drawn through an aerosol-generating article in the longitudinal direction.

As mentioned above, an aerosol-generating article in accordance with the present invention comprises a rod of aerosol-generating substrate. Further, an aerosol-generating article in accordance with the present invention comprises one or more elements provided downstream of the aerosol-generating substrate. The one or more elements downstream of the rod of aerosolgenerating substrate form a downstream section of the aerosol-generating article. Additionally, an aerosol-generating article in accordance with the present invention comprises an element provided upstream of the aerosol-generating substrate. The element upstream of the rod of aerosol-generating substrate defines an upstream section of the aerosol-generating article.

The rod of aerosol-generating substrate is preferably circumscribed by a wrapper, such as a plug wrap.

The rod of aerosol-generating substrate preferably has a length of at least about 8 millimetres. Preferably, the rod of aerosol-generating substrate has a length of at least about 9 millimetres. More preferably, the rod of aerosol-generating substrate has a length of at least about 10 millimetres.

For example, the rod of aerosol-generating substrate preferably has a length of between about 8 millimetres and about 16 millimetres, or between about 9 millimetres and about 15 millimetres, or between about 10 millimetres and about 14 millimetres. The rod of aerosolgenerating substrate may have a length of about 12 millimetres. Preferably the ratio of the length of the rod of aerosol-generating substrate to the total length of the aerosol-generating article is at least about 0.15, more preferably at least about 0.2, most preferably at least about 0.22.

Preferably, the ratio of the length of the rod of aerosol-generating substrate to the total length of the aerosol-generating article is less than or equal to 0.35, more preferably less than or equal to about 0.33, more preferably less than or equal to about 0.3.

The ratio of the length of the rod of aerosol-generating substrate to the total length of the aerosol-generating article is preferably approximately 0.25.

The rod of aerosol-generating substrate preferably has an external diameter that is approximately equal to the external diameter of the aerosol-generating article.

The “external diameter of the rod of aerosol-generating substrate” may be calculated as the average of a plurality of measurements of the diameter of the rod of aerosol-generating substrate taken at different locations along the length of the rod of aerosol-generating substrate.

Preferably, the rod of aerosol-generating substrate has an external diameter of at least about 5 millimetres. More preferably, the rod of aerosol-generating substrate has an external diameter of at least about 6 millimetres. Even more preferably, the rod of aerosol-generating substrate has an external diameter of at least about 7 millimetres.

The rod of aerosol-generating substrate preferably has an external diameter of less than or equal to about 12 millimetres. More preferably, the rod of aerosol-generating substrate has an external diameter of less than or equal to about 10 millimetres. Even more preferably, the rod of aerosol-generating substrate has an external diameter of less than or equal to about 8 millimetres.

In general, it has been observed that the smaller the diameter of the rod of aerosolgenerating substrate, the lower the temperature that is required to raise a core temperature of the rod of aerosol-generating substrate such that sufficient amounts of vaporizable species are released from the aerosol-generating substrate to form a desired amount of aerosol. At the same time, without wishing to be bound by theory, it is understood that a smaller diameter of the rod of aerosol-generating substrate allows for a faster penetration of heat supplied to the aerosolgenerating article into the entire volume of aerosol-generating substrate. Nevertheless, where the diameter of the rod of aerosol-generating substrate is too small, a volume-to-surface ratio of the aerosol-generating substrate becomes less favourable, as the amount of available aerosolgenerating substrate diminishes.

A diameter of the rod of aerosol-generating substrate falling within the ranges described herein is particularly advantageous in terms of a balance between energy consumption and aerosol delivery. This advantage is felt in particular when an aerosol-generating article comprising a rod of aerosol-generating substrate having a diameter as described herein is used in combination with an external heater arranged around the periphery of the aerosol-generating article. Under such operating conditions, it has been observed that less thermal energy is required to achieve a sufficiently high temperature at the core of the rod of aerosol-generating substrate and, in general, at the core of the article. Thus, when operating at lower temperatures, a desired target temperature at the core of the aerosol-generating substrate may be achieved within a desirably reduced time frame and by a lower energy consumption.

The rod of aerosol-generating substrate may have an external diameter from about 5 millimetres to about 12 millimetres, preferably from about 6 millimetres to about 12 millimetres, more preferably from about 7 millimetres to about 12 millimetres. The rod of aerosol-generating substrate may have an external diameter from about 5 millimetres to about 10 millimetres, preferably from about 6 millimetres to about 10 millimetres, more preferably from about 7 millimetres to about 10 millimetres. The rod of aerosol-generating substrate has an external diameter from about 5 millimetres to about 8 millimetres, preferably from about 6 millimetres to about 8 millimetres, more preferably from about 7 millimetres to about 8 millimetres.

Preferably, the rod of aerosol-generating substrate has an external diameter of less than about 7.5 millimetres. By way of example, the rod of aerosol-generating substrate may an external diameter of about 7.2 millimetres.

Preferably, the rod of aerosol-generating substrate has a substantially uniform crosssection along the length of the rod. Particularly preferably, the rod of aerosol-generating substrate has a substantially circular cross-section.

In an aerosol-generating article in accordance with the present invention, a ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosolgenerating article may be less than or equal to about 0.60. Preferably, a ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosol-generating article may be less than or equal to about 0.50. More preferably, a ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosol-generating article may be less than or equal to about 0.40. Even more preferably, a ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosol-generating article may be less than or equal to about 0.30.

In an aerosol-generating article in accordance with the present invention, a ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosolgenerating article may be at least about 0.10. Preferably, a ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosol-generating article may be at least about 0.15. More preferably, a ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosol-generating article may be at least about 0.20. Preferably, a ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosol-generating article may be at least about 0.25.

A ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosol-generating article may be from about 0.10 to about 0.60, preferably from about 0.15 to about 0.60, more preferably from about 0.20 to about 0.60, even more preferably from about 0.25 to about 0.60. A ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosol-generating article may be from about 0.10 to about 0.50, preferably from about 0.15 to about 0.50, more preferably from about 0.20 to about 0.50, even more preferably from about 0.25 to about 0.50. A ratio between the length of the rod of aerosolgenerating substrate and an overall length of the aerosol-generating article may be from about 0.10 to about 0.40, preferably from about 0.15 to about 0.40, more preferably from about 0.20 to about 0.40, even more preferably from about 0.25 to about 0.40. By way of example, a ratio between the length of the rod of aerosol-generating substrate and an overall length of the aerosolgenerating article may be from about 0.25 to about 0.30, preferably about 0.27.

Preferably, the density of the aerosol-generating substrate is at least about 150 mg per cubic centimetre. More preferably, the density of the aerosol-generating substrate is at least about 175 mg per cubic centimetre. More preferably, the density of the aerosol-generating substrate is at least about 200 mg per cubic centimetre. Even more preferably, the density of the aerosol-generating substrate is at least about 250 mg per cubic centimetre.

Preferably, the density of the aerosol-generating substrate is less than or equal to about 500 mg per cubic centimetre. More preferably, the density of the aerosol-generating substrate is less than or equal to about 450 mg per cubic centimetre. More preferably, the density of the aerosol-generating substrate is less than or equal to about 400 mg per cubic centimetre. Even more preferably, the density of the aerosol-generating substrate is less than or equal to about 350 mg per cubic centimetre.

For example, the density of the aerosol-generating substrate is preferably from about 150 mg per cubic centimetre to about 500 mg per cubic centimetre, preferably from about 175 mg per cubic centimetre to about 450 mg per cubic centimetre, more preferably from about 200 mg per cubic centimetre to about 400 mg per cubic centimetre, even more preferably from 250 mg per cubic centimetre to 350 mg per cubic centimetre. The density of the aerosol-generating substrate is preferably about 300 mg per cubic centimetre.

The rod of aerosol-generating substrate preferably comprises shredded tobacco material, for example tobacco cut filler, having a density of between about 150 mg per cubic centimetre and about 500 mg per cubic centimetre, preferably between about 175 mg per cubic centimetre and about 450 mg per cubic centimetre, more preferably between about 200 mg per cubic centimetre and about 400 mg per cubic centimetre, more preferably between about 250 mg per cubic centimetre and about 350 mg per cubic centimetre, most preferably about 300 mg per cubic centimetre.

The RTD of the rod of aerosol-generating substrate is preferably less than or equal to about 10 millimetres H₂O. More preferably, the RTD of the rod of aerosol-generating substrate is less than or equal to about 9 millimetres H₂O. Even more preferably, the RTD of the rod of aerosol-generating substrate is less than or equal to about 8 millimetres H₂O.

The RTD of the rod of aerosol-generating substrate is preferably at least about 4 millimetres H₂O. More preferably, the RTD of the rod of aerosol-generating substrate is at least about 5 millimetres H₂O. Even more preferably, the RTD of the rod of aerosol-generating substrate is at least about 6 millimetres H₂O.

An RTD of the rod of aerosol-generating substrate may be from about 4 millimetres H₂O to about 10 millimetres H₂O, preferably from about 5 millimetres H₂O to about 10 millimetres H₂O, preferably from about 6 millimetres H₂O to about 25 millimetres H₂O. The RTD of the rod of aerosol-generating substrate may be from about 4 millimetres H₂O to about 20 millimetres H₂O, preferably from about 5 millimetres H₂O to about 18 millimetres H₂O preferably from about 6 millimetres H₂O to about 16 millimetres H₂O. The RTD of the rod of aerosol-generating substrate may be from about 4 millimetres H₂O to about 15 millimetres H₂O, preferably from about 5 millimetres H₂O to about 14 millimetres H₂O, more preferably from about 6 millimetres H₂O to about 12 millimetres H₂O.

The aerosol-generating substrate may be a solid aerosol-generating substrate. The aerosol-generating substrate preferably comprises an aerosol former. The aerosol former may be any suitable known compound or mixture of compounds that, in use, facilitates formation of a dense and stable aerosol. The aerosol former may be facilitating that the aerosol is substantially resistant to thermal degradation at temperatures typically applied during use of the aerosolgenerating article. Suitable aerosol formers are for example: polyhydric alcohols such as, for example, triethylene glycol, 1 ,3-butanediol, propylene glycol and glycerine; esters of polyhydric alcohols such as, for example, glycerol mono-, di- or triacetate; aliphatic esters of mono-, di- or polycarboxylic acids such as, for example, dimethyl dodecanedioate and dimethyl tetradecanedioate; and combinations thereof.

Preferably, the aerosol former comprises one or more of glycerine and propylene glycol. The aerosol former may consist of glycerine or propylene glycol or of a combination of glycerine and propylene glycol.

Preferably, the aerosol-generating substrate comprises at least 5 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate. In other words, the aerosol-generating substrate has an aerosol former content of at least 5 percent on a dry weight basis. The aerosol-generating substrate may comprise at least 7 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate. The aerosol-generating substrate may comprise at least 10 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate. The aerosol-generating substrate may comprise at least 12 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate. The aerosol-generating substrate may comprise at least 13 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

The aerosol-generating substrate may comprise less than or equal to 22 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate. The aerosolgenerating substrate may comprise less than or equal to 19 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate. The aerosol-generating substrate may comprise less than or equal to 16 percent by weight of aerosol former on a dry weight basis of the aerosol-generating substrate.

The aerosol-generating substrate may comprise between 10 percent and 22 percent by weight on a dry weight basis of the aerosol-generating substrate, more preferably, the amount of aerosol former is between 12 percent and 19 percent by weight on a dry weight basis of the aerosol-generating substrate, most for example the amount of aerosol former is between 13 percent and 16 percent by weight on a dry weight basis of the aerosol-generating substrate.

The aerosol-generating substrate may comprise shredded tobacco material. For example, the shredded tobacco material may be in the form of cut filler. The shredded tobacco material may be in the form of a shredded sheet of homogenised tobacco material.

Within the context of the present specification, the term “cut filler” is used to describe to a blend of shredded plant material, such as tobacco plant material, including, in particular, one or more of leaf lamina, processed stems and ribs, homogenised plant material.

Preferably, the amount of aerosol former is at least 5 percent by weight on a dry weight basis of the cut filler, preferably between 10 percent and 22 percent by weight on a dry weight basis of the cut filler, more preferably, the amount of aerosol former is between 12 percent and 19 percent by weight on a dry weight basis of the cut filler, for example the amount of aerosol former is between 13 percent and 16 percent by weight on a dry weight basis of the cut filler. When aerosol former is added to the cut filler in the amounts described above, the cut filler may become relatively sticky. This advantageously help retain the cut filler at a predetermined location within the article, as the particles of cut filler display a tendency to adhere to surrounding cut filler particles as well as to surrounding surfaces (for example, the internal surface of a wrapper circumscribing the cut filler).

The amount of aerosol former may have a target value of about 13 percent or 18 percent by weight on a dry weight basis of the cut filler. The most efficient amount of aerosol former will depend also on the cut filler, whether the cut filler comprises plant lamina or homogenized plant material. For example, among other factors, the type of cut filler will determine to which extent the aerosol-former can facilitate the release of substances from the cut filler.

For these reasons, a rod of aerosol-generating substrate comprising cut filler as described above is capable of efficiently generating sufficient amount of aerosol at relatively low temperatures. A temperature of between 150 degrees Celsius and 200 degrees Celsius in the heating chamber may be sufficient for one such cut filler to generate sufficient amounts of aerosol while in aerosol-generating devices using tobacco cast leave sheets typically temperatures of about 250 degrees Celsius are employed.

A further advantage connected with operating at lower temperatures is that there is a reduced need to cool down the aerosol. As generally low temperatures are used, a simpler cooling function may be sufficient. This in turn allows using a simpler and less complex structure of the aerosol-generating article.

The aerosol-generating substrate may comprise homogenised plant material, preferably a homogenised tobacco material.

As used herein, the term “homogenised plant material” encompasses any plant material formed by the agglomeration of particles of plant. For example, sheets or webs of homogenised tobacco material for the aerosol-generating substrates of the present invention may be formed by agglomerating particles of tobacco material obtained by pulverising, grinding or comminuting plant material and optionally one or more of tobacco leaf lamina and tobacco leaf stems. The homogenised plant material may be produced by casting, extrusion, paper making processes or other any other suitable processes known in the art.

The homogenised plant material can be provided in any suitable form.

The homogenised plant material may be in the form of one or more sheets. As used herein with reference to the invention, the term “sheet” describes a laminar element having a width and length substantially greater than the thickness thereof.

The homogenised plant material may be in the form of a plurality of pellets or granules.

The homogenised plant material may be in the form of a plurality of strands, strips or shreds. As used herein, the term “strand” describes an elongate element of material having a length that is substantially greater than the width and thickness thereof. The term “strand” should be considered to encompass strips, shreds and any other homogenised plant material having a similar form. The strands of homogenised plant material may be formed from a sheet of homogenised plant material, for example by cutting or shredding, or by other methods, for example, by an extrusion method.

The strands may be formed in situ within the aerosol-generating substrate as a result of the splitting or cracking of a sheet of homogenised plant material during formation of the aerosolgenerating substrate, for example, as a result of crimping. The strands of homogenised plant material within the aerosol-generating substrate may be separate from each other. Each strand of homogenised plant material within the aerosol-generating substrate may be at least partially connected to an adjacent strand or strands along the length of the strands. For example, adjacent strands may be connected by one or more fibres. This may occur, for example, where the strands have been formed due to the splitting of a sheet of homogenised plant material during production of the aerosol-generating substrate, as described above. The homogenised plant material may be a homogenised tobacco material comprising tobacco particles. Sheets of such homogenised tobacco material may have a tobacco content of at least about 40 percent by weight on a dry weight basis, more preferably of at least about 50 percent by weight on a dry weight basis more preferably at least about 70 percent by weight on a dry weight basis and most preferably at least about 90 percent by weight on a dry weight basis.

With reference to the present invention, the term “tobacco particles” describes particles of any plant member of the genus Nicotiana. The term “tobacco particles” encompasses ground or powdered tobacco leaf lamina, ground or powdered tobacco leaf stems, tobacco dust, tobacco fines, and other particulate tobacco by-products formed during the treating, handling and shipping of tobacco. The tobacco particles are preferably substantially all derived from tobacco leaf lamina. By contrast, isolated nicotine and nicotine salts are compounds derived from tobacco but are not considered tobacco particles for purposes of the invention and are not included in the percentage of particulate plant material.

The homogenised plant material may further comprise one or more aerosol formers. Upon volatilisation, an aerosol former can convey other vaporised compounds released from the aerosol-generating substrate upon heating, such as nicotine and flavourants, in an aerosol. Suitable aerosol formers for inclusion in the homogenised plant material are known in the art and include, but are not limited to: polyhydric alcohols, such as triethylene glycol, propylene glycol, 1 ,3-butanediol and glycerol; esters of polyhydric alcohols, such as glycerol mono-, di- or triacetate; and aliphatic esters of mono-, di- or polycarboxylic acids, such as dimethyl dodecanedioate and dimethyl tetradecanedioate.

The homogenised plant material may have an aerosol former content of between about 5 percent and about 30 percent by weight on a dry weight basis, such as between about 10 percent and about 25 percent by weight on a dry weight basis, or between about 15 percent and about 20 percent by weight on a dry weight basis. The aerosol former may act as a humectant in the homogenised plant material.

As set out above, the rod of aerosol-generating substrate may be circumscribed by a wrapper. The wrapper circumscribing the rod of aerosol-generating substrate may be a paper wrapper or a non-paper wrapper. Suitable paper wrappers for use in the invention are known in the art and include, but are not limited to: cigarette papers; and filter plug wraps. Suitable nonpaper wrappers for use in the invention are known in the art and include, but are not limited to sheets of homogenised tobacco materials.

A paper wrapper may have a grammage of at least 15 gsm, preferably at least 20 gsm. The paper wrapper may have a grammage of less than or equal to 35 gsm, preferably less than or equal to 30 gsm. The paper wrapper may have a grammage from 15 gsm to 35 gsm, preferably from 20 gsm to 30 gsm. The paper wrapper may have a grammage of 25 gsm. A paper wrapper may have a thickness of at least 25 micrometres, preferably at least 30 micrometres, more preferably at least 35 micrometres. The paper wrapper may have a thickness of less than or equal to 55 micrometres, preferably less than or equal to 50 micrometres, more preferably less than or equal to 45 micrometres. The paper wrapper may have a thickness from 25 micrometres to 55 micrometres, preferably from 30 micrometres to 50 micrometres, more preferably from 35 micrometres to 45 micrometres. The paper wrapper may have a thickness of 40 microns.

The wrapper may be formed of a laminate material comprising a plurality of layers. Preferably, the wrapper is formed of an aluminium co-laminated sheet. The use of a co-laminated sheet comprising aluminium advantageously prevents combustion of the aerosol-generating substrate in the event that the aerosol-generating substrate should be ignited, rather than heated in the intended manner.

A paper layer of the co-laminated sheet may have a grammage of at least 35 gsm, preferably at least 40 gsm. The paper layer of the co-laminated sheet may have a grammage of less than or equal to 55 gsm, preferably less than or equal to 50 gsm. The paper layer of the colaminated sheet may have a grammage from 35 gsm to 55 gsm, preferably from 40 gsm to 50 gsm. The paper layer of the co-laminated sheet may have a grammage of 45 gsm.

A paper layer of the co-laminated sheet may have a thickness of at least 50 micrometres, preferably at least 55 micrometres, more preferably at least 60 micrometres. The paper layer of the co-laminated sheet may have a thickness of less than or equal to 80 micrometres, preferably less than or equal to 75 micrometres, more preferably less than or equal to 70 micrometres.

The paper layer of the co-laminated sheet may have a thickness from 50 micrometres to 80 micrometres, preferably from 55 micrometres to 75 micrometres, more preferably from 60 micrometres to 70 micrometres. The paper layer of the co-laminated sheet may have a thickness of 65 microns.

A metallic layer of the co-laminated sheet may have a grammage of at least 12 gsm, preferably at least 15 gsm. The metallic layer of the co-laminated sheet may have a grammage of less than or equal to 25 gsm, preferably less than or equal to 20 gsm. The metallic layer of the co-laminated sheet may have a grammage from 12 gsm to 25 gsm, preferably from 15 gsm to 20 gsm. The metallic layer of the co-laminated sheet may have a grammage of 17 gsm.

A metallic layer of the co-laminated sheet may have a thickness of at least 2 micrometres, preferably at least 3 micrometres, more preferably at least 5 micrometres. The metallic layer of the co-laminated sheet may have a thickness of less than or equal to 15 micrometres, preferably less than or equal to 12 micrometres, more preferably less than or equal to 10 micrometres.

The metallic layer of the co-laminated sheet may have a thickness from 2 micrometres to 15 micrometres, preferably from 3 micrometres to 12 micrometres, more preferably from 5 micrometres to 10 micrometres. The metallic layer of the co-laminated sheet may have a thickness of 6 microns. The wrapper circumscribing the rod of aerosol-generating substrate may be a paper wrapper comprising PVOH (polyvinyl alcohol) or silicon. Addition of PVOH (polyvinyl alcohol) or silicon may improve the grease barrier properties of the wrapper.

The PVOH or silicon may be applied to the paper layer as a surface coating, such as disposed on an exterior surface of the paper layer of the wrapper circumscribing the rod of aerosol-generating substrate. The PVOH or silicon may be disposed on and form a layer on the exterior surface of the paper layer of the wrapper. The PVOH or silicon may be disposed on an interior surface of the paper layer of the wrapper. The PVOH or silicon may be disposed on and form a layer on the interior surface of the paper layer of the aerosol generating article. The PVOH or silicon may be disposed on the interior surface and the exterior surface of the paper layer of the wrapper. The PVOH or silicon may be disposed on and form a layer on the interior surface and the exterior surface of the paper layer of the wrapper.

The paper wrapper comprising PVOH or silicon may have a grammage of at least 20 gsm, preferably at least 25 gsm, more preferably at least 30 gsm. The paper wrapper comprising PVOH or silicon may have a grammage of less than or equal to 50 gsm, preferably less than or equal to 45 gsm, more preferably less than or equal to 40 gsm. The paper wrapper comprising PVOH or silicon may have a grammage from 20 gsm to 50 gsm, preferably from 25 gsm to 45 gsm, more preferably from 30 gsm to 40 gsm. The paper wrapper comprising PVOH or silicon may have a grammage of about 35 gsm.

The paper wrapper comprising PVOH or silicon may have a thickness of at least 25 micrometres, preferably at least 30 micrometres, more preferably at least 35 micrometres. The paper wrapper comprising PVOH or silicon may have a thickness of less than or equal to 50 micrometres, preferably less than or equal to 45 micrometres, more preferably less than or equal to 40 micrometres. The paper wrapper comprising PVOH or silicon may have a thickness from 25 micrometres to 50 micrometres, preferably from 30 micrometres to 45 micrometres, more preferably from 35 micrometres to 40 micrometres. The paper wrapper comprising PVOH or silicon may have a thickness of 37 micrometres.

As mentioned in the present disclosure, the present invention preferably comprises at least one air channelling element or segment. The downstream section of the aerosol-generating article may comprise an air channelling element. Such an air channelling element may be referred to as a downstream air channelling element, an aerosol-cooling element, or a support element.

An upstream section of the aerosol-generating article may comprise an air channelling element. Such an air channelling element may be referred to as an upstream air channelling element, an upstream element, or a front plug.

Both the upstream and downstream sections of the aerosol-generating article may each comprise an air channelling element. Features described in the present disclosure in relation to an air channelling element may respectively apply to a downstream air channelling element (in other words, an air channelling element that is located downstream of the rod of aerosolgenerating substrate) and to an upstream air channelling element (in other words, an air channelling element that is located upstream of the rod of aerosol-generating substrate).

An upstream air channelling element may abut the rod of aerosol-generating substrate. The upstream air channelling element may abut the upstream end of the rod of aerosol-generating substrate. The upstream air channelling element may be located upstream of the rod of aerosolgenerating substrate. The upstream air channelling element may be located at the upstream end of the aerosol-generating article.

A downstream air channelling element may abut the rod of aerosol-generating substrate. The downstream air channelling element may abut the downstream end of the rod of aerosolgenerating substrate. The downstream air channelling element may be located downstream of the rod of aerosol-generating substrate. The downstream air channelling element may be located between the rod of aerosol-generating substrate and any other component or element of the downstream section, such as a hollow tubular element or a mouthpiece element. The downstream air channelling element may abut the mouthpiece element. The downstream air channelling element may abut the upstream end of the mouthpiece element. The downstream air channelling element may be located upstream of the downstream end of the aerosol-generating article.

An air channelling element of the present disclosure may comprise a body. The body of an air channelling element may comprise a core portion and a peripheral portion. The core and peripheral portion may extend longitudinally. The peripheral portion may surround or circumscribe the core portion. The body is preferably a cylindrical body having a substantially circular cross-section.

The core portion may comprise the centre of the body of an air channelling element. The core portion of the body preferably refers to a circular core portion located in the centre of the cross-section of the body.

The core portion of the body may have a radius that is at least 25 percent of the radius of the body. The core portion of the body may have a radius that is at least 30 percent of the radius of the body. The core portion of the body may have a radius that is at least 50 percent of the radius of the body. The core portion of the body may have a radius that is no more than 80 percent of the radius of the body. The core portion of the body may have a radius that is no more than 75 percent of the radius of the body.

The peripheral portion of an air channelling element may comprise an annular portion of the body surrounding the core portion. In other words, the peripheral portion may occupy the rest of the cross-section of the body of an air channelling element. The peripheral portion may extend between the outer periphery or circumference of an air channelling element and the core portion.

An air channelling element may comprise an outer air passageway. An outer air passageway may be an external air passageway. An outer air passageway may be defined on an external surface of the body of an air channelling element. An outer air passageway may refer to an air passageway located away from the central axis of the air channelling element. An outer air passageway may be an internal air passageway located within the material or body of the air channelling element or an external air passageway provided on an external surface of the air channelling element. An outer air passageway may be referred to as a peripheral air passageway. An outer air passageway may extend from one end of the air channelling element to the other end of the air channelling element. An outer air passageway may extend from the upstream end of the air channelling element to the downstream end of the air channelling element.

An outer air passageway may be an internal air passageway. An outer air passageway may be defined within the body of an air channelling element. An outer air passageway may be defined in or within the peripheral portion of the body of an air channelling element. An outer air passageway may be an internal passageway or channel extending along an air channelling element.

An air channelling element may comprise one or more outer air passageways. An air channelling element may comprise at least two outer air passageways, preferably at least three outer air passageways, more preferably at least four outer air passageways. The outer air passageways may be evenly or uniformly distributed within the air channelling element. The outer air passageways may be evenly or uniformly distributed about the core portion of an air channelling element. The outer air passageways, either in the form of an internal cavity or air passageway or an external air passageway, preferably extend from an upstream end of the air channelling element to a downstream end of the air channelling element. The outer air passageways, either in the form of an internal cavity or air passageway or an external air passageway, preferably extend continuously from an upstream end of the air channelling element to a downstream end of the air channelling element.

An outer air passageway may comprise a groove defined on an external surface of an air channelling element. An air channelling element may comprise at least one groove. An air channelling element may comprise at least two grooves, preferably at least three grooves, more preferably at least four grooves, even more preferably at least five grooves. The grooves may be evenly or uniformly distributed about the core portion of an air channelling element. The grooves may be evenly or uniformly distributed around the body of an air channelling element.

Any outer air passageway, internal air passageway or groove of an air channelling element may extend from one end of the air channelling element to the other end of the air channelling element. Any outer air passageway, internal air passageway or groove of an air channelling element may extend from the upstream end of the air channelling element to the downstream end of the air channelling element. Any outer air passageway, internal air passageway or groove of an air channelling element may extend continuously from the upstream end of the air channelling element to the downstream end of the air channelling element. Any outer air passageway, internal air passageway or groove of an air channelling element may extend unobstructed from the upstream end of the air channelling element to the downstream end of the air channelling element, such that air or aerosol may flow through from end to end of the air channelling element.

Providing a plurality of outer air passageways, such as grooves or internal channels, increases the amount of air or aerosol flow through the peripheral portion of an air channelling element and likely through a peripheral portion of the aerosol-generating substrate, thereby increasing heat exchange and improving aerosol nucleation. Particularly in the context of a downstream air channelling element, the provision of external air passageways, preferably in the form of grooves, may improve heat exchange of the aerosol flowing through the outer air passageways due to the proximity of the aerosol to the exterior of the aerosol-generating article.

Each outer air passageway may trace or follow a substantially straight path. Each outer air passageway may be substantially parallel to each other. Each outer air passageway may trace a helical path. Each groove may trace a helical path about an air channelling element or on an external surface thereof. By tracing or following a helical path, the outer air passageway may effectively follow a longer path from the upstream end of an air channelling element to the downstream end, thereby providing more time for aerosol to cool. Each groove may trace a sinusoidal path or any other waveform path. The waveform may include a square wave, a triangular wave, or a sawtooth wave.

Each outer air passageway may be defined by an internal cavity extending along an air channelling element. An outer air passageway that extends within the body of an air channelling element may have a substantially circular cross-section. A radius of such an internal passageway may be at least about 0.25 mm, preferably at least about 0.5 mm, more preferably at least about 1 mm. A radius of such an internal passageway may be no more than about 2 mm.

When an outer or peripheral air passageway is internally defined within the material of the air channelling element, the outer air passageway may be located at a distance away from the periphery of the air channelling element. When an outer or peripheral air passageway is internally defined within the material of the air channelling element, each or the outer air passageway may be located at a distance away from the periphery of the air channelling element. Such a distance may be no more than about 2 mm, preferably no more than about 1.5 mm, more preferably no more than about 1 mm, even more preferably no more than about 0.75 mm. Such a distance preferably refers to a distance measured from the outer edge of the outer air passageway to the outermost edge or periphery of the air channelling element.

A depth of an outer air passageway defined by a groove may be at least about 0.5 mm. A depth of an outer air passageway defined by a groove may be at least about 0.7 mm. A depth of an outer air passageway defined by a groove may be at least about 1 mm. A depth of an outer air passageway defined by a groove may be no greater than about 1 .5 mm. A depth of an outer air passageway defined by a groove may be no greater than about 2 mm. A ratio of the total cross-sectional area of outer air passageways (in other words, the sum of all outer air passageways) to the total cross-sectional area of an air channelling element may be at least about 2.5 percent. Such a ratio may be at least about 5 percent, preferably at least about 10 percent, more preferably at least about 15 percent and even more preferably at least about 25 percent. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of an air channelling element may be at least about 30 percent. The total cross-sectional area of an air channelling element may refer to the internal cross-sectional area of the aerosol-generating article at the position of an air channelling element.

A ratio of the total cross-sectional area of outer air passageways to the total cross- sectional area of an air channelling element may be no greater than about 60 percent. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of an air channelling element may be no greater than about 50 percent. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of an air channelling element may be no greater than about 40 percent. The total cross-sectional area of an air channelling element may refer to the cross-sectional area of an air channelling element if an air channelling element was completely solid. In other words, the total cross-sectional area of an air channelling element may be based on the largest outer diameter of an air channelling element. As discussed above, the outer air passageways may comprise grooves defined on an external surface of an air channelling element.

An air channelling element, either upstream or downstream, may be wrapped by a wrapper. Such a wrapper may have features in accordance with any wrappers described in the present disclosure. A wrapper surrounding an air channelling element may be substantially air impermeable. In embodiments comprising one or more grooves on the external surface of an air channelling element, a wrapper circumscribing an air channelling element may define a boundary for the one or more outer air passageways, which may be defined by the one or more grooves. In other words, the one or more outer air passageways of an air channelling element may be defined by the wrapper and the one or more grooves.

In embodiments where the outer air passageways are defined by one or more grooves around the periphery of an air channelling element, the external surface of an air channelling element defined by grooves may define a wet surface and the external surface of an air channelling element not defined by grooves may define a non-wet surface. The term ‘wet surface’ refers to the surface of an air channelling element that is configured to be in contact with air or aerosol travelling through the grooves. The ‘non-wet surface’ may be in contact with a wrapper circumscribing an air channelling element. In the present disclosure, the term “external surface of an air channelling element” preferably refers to an external longitudinal surface of an air channelling element, extending parallel to a longitudinal direction of an air channelling element or the aerosol-generating article. The ratio of the wet surface area of an air channelling element to the non-wet surface area of an air channelling element may be at least about 25 percent. The ratio of the wet surface area of an air channelling element to the non-wet surface area of an air channelling element may be at least about 50 percent. The ratio of the wet surface area of an air channelling element to the non-wet surface area of an air channelling element may be at least about 1 .

The ratio of the wet surface area of an air channelling element to the non-wet surface area of an air channelling element may be no greater than about 3. The ratio of the wet surface area of an air channelling element to the non-wet surface area of an air channelling element may be no greater than about 2.5. The ratio of the wet surface area of an air channelling element to the non-wet surface area of an air channelling element may be no greater than about 2.

The core portion of an air channelling element is preferably substantially solid. This may advantageously prevent the inadvertent exit or migration of the aerosol-generating substrate material and encourage the flow of air or aerosol through any air passageways present in the peripheral portion of an air channelling element. In other words, the core portion of an air channelling element may not comprise or define a central, internal cavity extending along an air channelling element. The outer air passageways, or grooves, of an air channelling element may therefore be the primary or sole paths for air or aerosol to travel through an air channelling element towards the aerosol-generating substrate or towards the downstream end of the aerosolgenerating article.

An air channelling element may comprise one or more inner air passageways. An air channelling element may comprise at least two inner air passageways. The core portion of an air channelling element may define the one or more inner air passageways. The one or more inner air passageways may be surrounded by one or more outer air passageways. Each inner air passageway may be defined as a longitudinal air channel or cavity extending along an air channelling element. Each inner air passageway may extend from an upstream end of the air channelling element to a downstream end of the air channelling element. Each inner air passageway may extend continuously from an upstream end of the air channelling element to a downstream end of the air channelling element.

The material of an air channelling element may be porous. However, the pores or voids inherent to the material of an air channelling element may not be considered to define the one or more inner air passageways or the one or more outer or external air passageways of the air channelling element. In other words, any air passageways are preferably formed in the material or body of an air channelling element through a manufacturing step.

A ratio of the total cross-sectional area of any inner air passageways to the total cross- sectional area of an air channelling element may be at least about 1 percent (or 0.01 ). A ratio of the total cross-sectional area of any inner air passageways to the total cross-sectional area of an air channelling element may be at least about 5 percent (or 0.05). A ratio of the total cross- sectional area of any inner air passageways to the total cross-sectional area of an air channelling element may be at least about 7.5 percent (or 0.075).

A ratio of the total cross-sectional area of any inner air passageways to the total cross- sectional area of an air channelling element may be no greater than about 20 percent (or 0.2). A ratio of the total cross-sectional area of any inner air passageways to the total cross-sectional area of an air channelling element may be no greater than about 15 percent. A ratio of the total cross-sectional area of any inner air passageways to the total cross-sectional area of an air channelling element may be no greater than about 10 percent.

A ratio of the total cross-sectional area of outer air passageways to the total cross- sectional area of any inner air passageways may be at least about 0.5. A ratio of the total cross- sectional area of outer air passageways to the total cross-sectional area of any inner air passageways may be at least about 1. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of any inner air passageways may be at least about 1 .5. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of any inner air passageways may be at least about 2. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of any inner air passageways may be at least about 3. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of any inner air passageways may be at least about 4. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of any inner air passageways may be at least about 5. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of any inner air passageways may be at least about 6.

A ratio of the total cross-sectional area of outer air passageways to the total cross- sectional area of any inner air passageways may be no greater than about 10. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of any inner air passageways may be no greater than about 7.5. A ratio of the total cross-sectional area of outer air passageways to the total cross-sectional area of any inner air passageways may be no greater than about 5.

The length of an air channelling element may be at least about 4 mm. The length of an air channelling element may be at least about 5 mm. The length of an air channelling element may be at least about 6 mm. The length of the air channelling element may be at least about 7 mm. The length of the air channelling element may be at least about 10 mm. The length of the air channelling element may be at least about 12 mm. The length of an air channelling element may be at least about 17 mm.

The length of an air channelling element may be less or equal than about 50 mm. The length of an air channelling element may be less or equal than about 25 mm. The length of an air channelling element may be less or equal than about 23 mm. The length of an air channelling element may be less or equal than about 20 mm. The length of an air channelling element may be less or equal than about 15 mm.

The length of an air channelling element may be between about 4 mm and about 50 mm, preferably about 4 mm and about 30 mm, more preferably about 4 mm and about 25 mm. The length of an air channelling element may be between about 4 mm and about 50 mm, preferably about 7 mm and about 30 mm, more preferably about 10 mm and about 25 mm. The length of an air channelling element may be between about 12 mm and about 20 mm. The length of an air channelling element may be between about 10 mm and about 15 mm. The length of an air channelling element may be between about 17 mm and about 23 mm.

Preferably, the length of an air channelling element may be about 12 mm. The length of an air channelling element may be about 16 mm. The length of an air channelling element may be about 20 mm.

Preferably, the length of a downstream air channelling element may be about 12 mm. The length of a downstream air channelling element may be about 16 mm. The length of a downstream air channelling element may be about 20 mm.

Preferably, the length of an upstream air channelling element may be about 4 mm. The length of an upstream air channelling element may be about 5 mm. The length of an upstream air channelling element may be about 6 mm.

Preferably, where both an upstream air channelling element and a downstream air channelling element are provided in the same aerosol-generating article, the length of a downstream air channelling element is greater than the length of an upstream air channelling element.

An air channelling element preferably has an outer diameter that is approximately equal to the outer diameter of the rod of aerosol-generating substrate and to the outer diameter of the aerosol-generating article. This ensures that any grooves or outer or inner air passageways of an air channelling element are obstructed at an end by the aerosol-generating substrate. In other words, the cross-section of any grooves or air passageways of an air channelling element may overlap the cross-section of the aerosol-generating substrate. The cross-section of any grooves or air passageways of an air channelling element may wholly overlap the cross-section of the aerosol-generating substrate. The cross-section of any grooves or air passageways of an air channelling element when projected onto the aerosol-generating substrate may fall within the cross-section of the aerosol-generating substrate, particularly when an air channelling element and the aerosol-generating substrate are assembled and aligned in the aerosol-generating article.

An air channelling element may have an outer diameter of between 5 millimetres and 12 millimetres, for example of between 5 millimetres and 10 millimetres or of between 6 millimetres and 8 millimetres. An air channelling element may have an external diameter of 7.2 millimetres plus or minus 10 percent. An air channelling element (or the body thereof) may be formed by thermoforming. Grooves defined on an air channelling element may be formed by thermoforming. Thermoforming advantageously may provide a cost-effective and efficient manufacturing process for an air channelling element, particularly when comprising external grooves. An air channelling element may be made by injection moulding or by extrusion.

An air channelling element (or the body thereof) may comprise (or may be formed by) a polymeric material. An air channelling element (or the body thereof) may comprise (or may be formed by) a plastic material. An air channelling element (or the body thereof) may comprise (or may be formed by) a thermoplastic material. An air channelling element (or the body thereof) may comprise (or may be formed by) polyethylene (PE). An air channelling element (or the body thereof) may comprise (or may be formed by) cellulose acetate.

An air channelling element may comprise, or may be formed by, a substantially impermeable material. An air channelling element may comprise, or may be formed by, a substantially air impermeable material. The material of an air channelling element may be substantially air impermeable. The usage of a substantially air impermeable material may force air or aerosol to flow rather exclusively through the inner or outer air passageways of the air channelling element.

An air channelling element may comprise (or may be formed by) paper. An air channelling element may comprise cardboard. An air channelling element may be formed from extruded paper.

An aerosol-generating article according to the present disclosure comprises an upstream section located upstream of the rod of aerosol-generating substrate. The upstream section is preferably located immediately upstream of the rod of aerosol-generating substrate. The upstream section preferably extends between the upstream end of the aerosol-generating article and the rod of aerosol-generating substrate.

The upstream section comprises an upstream element located upstream of the rod of aerosol-generating substrate. Suitable upstream elements are described within the present disclosure. The upstream element may be an upstream plug element (or front plug). The upstream element may be an upstream hollow tubular element. The upstream element may be an upstream air channelling element.

The upstream element is preferably an upstream air channelling element. An upstream air channelling element may abut the rod of aerosol-generating substrate. The upstream air channelling element may abut the upstream end of the rod of aerosol-generating substrate. The upstream air channelling element may be located upstream of the rod of aerosol-generating substrate. The upstream air channelling element may be located at the upstream end of the aerosol-generating article. Accordingly, the upstream element or upstream air channelling element may comprise features associated with an air channelling element, as described in the present disclosure. Similarly, features described herein in relation to an upstream element may also be present in an upstream air channelling element.

An upstream element advantageously prevents direct physical contact with the upstream end of the aerosol-generating substrate, in addition to the air channelling benefits associated with an air channelling element described in the present disclosure. For example, where the aerosolgenerating substrate comprises a susceptor element, the upstream element may prevent direct physical contact with the upstream end of the susceptor element. This helps to prevent the displacement or deformation of the susceptor element during handling or transport of the aerosolgenerating article. This in turn helps to secure the form and position of the susceptor element.

Furthermore, the presence of an upstream element helps to prevent any loss of the substrate, which may be advantageous, for example, if the substrate contains particulate plant material.

Where the aerosol-generating substrate comprises shredded tobacco, such as tobacco cut filler, the upstream section or element thereof may additionally help to prevent the loss of loose particles of tobacco from the upstream end of the article.

The upstream section, or upstream element thereof, may also additionally provide a degree of protection to the aerosol-generating substrate during storage, as it covers at least to some extent the upstream end of the aerosol-generating substrate, which may otherwise be exposed.

For aerosol-generating articles that are intended to be inserted into a cavity in an aerosolgenerating device such that the aerosol-generating substrate can be externally heated within the cavity, the upstream section, or upstream element thereof, may advantageously facilitate the insertion of the upstream end of the article into the cavity. The inclusion of the upstream element may additionally protect the end of the rod of aerosol-generating substrate during the insertion of the article into the cavity such that the risk of damage to the substrate is minimised.

The upstream section, or upstream element thereof, may also provide an improved appearance to the upstream end of the aerosol-generating article. Furthermore, if desired, the upstream section, or upstream element thereof, may be used to provide information on the aerosol-generating article, such as information on brand, flavour, content, or details of the aerosolgenerating device that the article is intended to be used with.

An upstream element may be a porous plug element. Preferably, an upstream element has a porosity of at least about 50 percent in the longitudinal direction of the aerosol-generating article. More preferably, an upstream element has a porosity of between about 50 percent and about 90 percent in the longitudinal direction. The porosity of an upstream element in the longitudinal direction is defined by the ratio of the cross-sectional area of material forming the upstream element and the internal cross-sectional area of the aerosol-generating article at the position of the upstream element.

An upstream element may be made of a porous material or may comprise a plurality of openings. This may, for example, be achieved through laser perforation. Preferably, the plurality of openings is distributed homogeneously over the cross-section of the upstream element.

The porosity or permeability of an upstream element may advantageously be designed in order to provide an aerosol-generating article with a particular overall resistance to draw (RTD) without substantially impacting the filtration provided by other portions of the article.

An upstream element may be formed from a material that is impermeable to air. In such embodiments, the aerosol-generating article may be configured such that air flows into the rod of aerosol-generating substrate through suitable ventilation means provided in a wrapper.

It may be desirable to minimise the RTD of an upstream element. For example, this may be the case for articles that are intended to be inserted the cavity of an aerosol-generating device such that the aerosol-generating substrate is externally heated, as described herein. For such articles, it is desirable to provide the article with as low an RTD as possible, so that the majority of the RTD experience by the consumer is provided by the aerosol-generating device and not the article.

The RTD of an upstream element is preferably less than or equal to about 10 millimetres H₂O. More preferably, the RTD of an upstream element is less than or equal to about 5 millimetres H₂O. Even more preferably, the RTD of an upstream element is less than or equal to about 2.5 millimetres H₂O. Even more preferably, the RTD of the upstream element is less than or equal to about 2 millimetres H₂O.

The RTD of an upstream element may be at least 0.1 millimetres H₂O, or at least about 0.25 millimetres H₂O or at least about 0.5 millimetres H₂O.

The RTD of an upstream element may be from about 0.1 millimetres H₂O to about 10 millimetres H₂O, preferably from about 0.25 millimetres H₂O to about 10 millimetres H₂O, preferably from about 0.5 millimetres H₂O to about 10 millimetres H₂O. The RTD of an upstream element is from about 0.1 millimetres H₂O to about 5 millimetres H₂O, preferably from about 0.25 millimetres H₂O to about 5 millimetres H₂O preferably from about 0.5 millimetres H₂O to about 5 millimetres H₂O. , the RTD of an upstream element may be from about 0.1 millimetres H₂O to about 2.5 millimetres H₂O, preferably from about 0.25 millimetres H₂O to about 2.5 millimetres H₂O, more preferably from about 0.5 millimetres H₂O to about 2.5 millimetres H₂O. The RTD of an upstream element is from about 0.1 millimetres H₂O to about 2 millimetres H₂O, preferably from about 0.25 millimetres H₂O to about 2 millimetres H₂O, more preferably from about 0.5 millimetres H₂O to about 2 millimetres H₂O, the RTD of an upstream element may be about 1 millimetre H₂O. Preferably, an upstream element has an RTD of less than about 2 millimetres H₂O per millimetre of length, more preferably less than about 1 .5 millimetres H₂O per millimetre of length, more preferably less than about 1 millimetre H₂O per millimetre of length, more preferably less than about 0.5 millimetres H₂O per millimetre of length, more preferably less than about 0.3 millimetres H₂O per millimetre of length, more preferably less than about 0.2 millimetres H₂O per millimetre of length.

Preferably, the upstream section, or an upstream element thereof, has an external diameter that is approximately equal to the external diameter of the aerosol-generating article. Preferably, the external diameter of the upstream section, or an upstream element thereof, is between about 6 millimetres and about 8 millimetres, more preferably between about 7 millimetres and about 7.5 millimetres. Preferably, the upstream section or an upstream element has an external diameter that is about 7.1 mm.

Preferably, the upstream section or an upstream element has a length of between about 2 millimetres and about 8 millimetres, more preferably between about 3 millimetres and about 7 millimetres, more preferably between about 4 millimetres and about 6 millimetres. The upstream section or an upstream element may have a length of about 5 millimetres.

The length of the upstream section or an upstream element can advantageously be varied in order to provide the desired total length of the aerosol-generating article. For example, where it is desired to reduce the length of one of the other components of the aerosol-generating article, the length of the upstream section or an upstream element may be increased in order to maintain the same overall length of the article.

The length of the upstream section, or an upstream element thereof, can be used to control the position of the aerosol-generating article within the cavity of an aerosol-generating device, for articles which are intended to be externally heated. This can advantageously ensure that the position of the aerosol-generating substrate within the cavity can be optimised for heating and the position of any ventilation can also be optimised.

The upstream section is preferably circumscribed by a wrapper, such as a plug wrap. The wrapper circumscribing the upstream section is preferably a stiff plug wrap, for example, a plug wrap having a basis weight of at least about 80 grams per square metre (gsm), or at least about 100 gsm, or at least about 110 gsm. This provides structural rigidity to the upstream section.

The upstream section is preferably connected to the rod of aerosol-generating substrate and optionally at least a part of the downstream section by means of an outer wrapper.

As mentioned above, an aerosol-generating article according to the present invention comprises a downstream section located downstream of the rod of aerosol-generating substrate. The downstream section is preferably located immediately downstream of the rod of aerosolgenerating substrate. The downstream section of the aerosol-generating article preferably extends between the rod of aerosol-generating substrate and the downstream end of the aerosol- generating article. The downstream section may comprise one or more elements, each of which are described in more detail within the present disclosure.

A length of the downstream section may be at least about 15 mm. A length of the downstream section may be at least about 20 mm. A length of the downstream section may be at least about 24 mm. A length of the downstream section may be at least about 26 mm.

A length of the downstream section may be equal to or less than (in other words, no more than) about 36 mm. A length of the downstream section may be equal to or less than about 32 mm. A length of the downstream section may be equal to or less than about 30 mm.

A length of the downstream section may be between about 15 mm and about 36 mm. A length of the downstream section may be between about 20 mm and about 36 mm. A length of the downstream section may be between about 24 mm and about 32 mm. A length of the downstream section may be between about 26 mm and about 30 mm.

Preferably, the downstream section comprises an air channelling element, in accordance with the present disclosure. The downstream air channelling element may be located downstream of the rod of aerosol-generating substrate. The downstream air channelling element may be located adjacent to the rod of aerosol-generating substrate. The downstream air channelling element may abut the downstream end of the rod of aerosol-generating substrate.

Preferably, the downstream section comprises a hollow tubular element. Preferably, the downstream section comprises a mouthpiece element. The downstream section may comprise, or may consist of, a hollow tubular element and a mouthpiece element, the hollow tubular element being located between the rod of aerosol-generating substrate and the mouthpiece element. The hollow tubular element may abut the rod of aerosol-generating substrate and the mouthpiece element.

If the downstream section comprises a downstream air channelling element, the hollow tubular element may be located downstream of a downstream air channelling element. The hollow tubular element may abut the downstream air channelling element. The hollow tubular element may be located between a downstream air channelling element and a mouthpiece element.

Providing a relatively long downstream section ensures that a suitable length of the aerosol-generating article protrudes from an aerosol-generating device when the article is received therein. Such a suitable protrusion length facilitates the ease of insertion and extraction of the article from the device, which also ensures that the upstream portions of the article are suitably inserted into the device with reduced risk of damage, particularly during insertion.

As used throughout the present disclosure, the terms “hollow tubular segment” or “hollow tubular element” denotes a generally elongate element defining a lumen or airflow passage along a longitudinal axis thereof. In particular, the term “tubular” will be used in the following with reference to a tubular element having a substantially cylindrical cross-section and defining at least one airflow conduit establishing an uninterrupted fluid communication between an upstream end of the tubular element and a downstream end of the tubular element. However, it will be understood that alternative geometries (for example, alternative cross-sectional shapes) of the tubular segment may be possible. The hollow tubular segment or element may be an individual, discrete element of the aerosol-generating article which has a defined length and thickness. In the present specification, a “hollow tubular segment” or “hollow tubular element” may also be referred to as a “hollow tube” or a “hollow tube segment”.

An internal volume defined by the hollow tubular element may be at least about 100 cubic millimetres. In other words, a volume of the cavity or lumen defined by the hollow tubular element may be at least about 100 cubic millimetres. Preferably, an internal volume defined by the hollow tubular element may be at least about 300 cubic millimetres. An internal volume defined by the hollow tubular element may be at least about 700 cubic millimetres.

An internal volume defined by the hollow tubular element may be less than or equal to about 1200 cubic millimetres. Preferably, an internal volume defined by the hollow tubular element may be less than or equal to about 1000 cubic millimetres. An internal volume defined by the hollow tubular element may be less than or equal to about 900 cubic millimetres.

An internal volume defined by the hollow tubular element may be between about 100 and about 1200 cubic millimetres. Preferably, an internal volume defined by the hollow tubular element may be between about 300 and about 1000 cubic millimetres. An internal volume defined by the hollow tubular element may be between about 700 and about 900 cubic millimetres.

In the context of the present invention, a hollow tubular segment provides an unrestricted flow channel. This means that the hollow tubular segment provides a negligible level of resistance to draw (RTD). The term “negligible level of RTD” is used to describe an RTD of less than 1 mm H₂O per 10 millimetres of length of the hollow tubular segment or hollow tubular element, preferably less than 0.4 mm H₂O per 10 millimetres of length of the hollow tubular segment or hollow tubular element, more preferably less than 0.1 mm H₂O per 10 millimetres of length of the hollow tubular segment or hollow tubular element.

The RTD of a hollow tubular element is preferably less than or equal to about 10 millimetres H₂O. More preferably, the RTD of a hollow tubular element is less than or equal to about 5 millimetres H₂O. Even more preferably, the RTD of a hollow tubular element is less than or equal to about 2.5 millimetres H₂O. Even more preferably, the RTD of the hollow tubular element is less than or equal to about 2 millimetres H₂O. Even more preferably, the RTD of the hollow tubular element is less than or equal to about 1 millimetre H₂O.

The RTD of a hollow tubular element may be at least 0 millimetres H₂O, or at least about 0.25 millimetres H₂O or at least about 0.5 millimetres H₂O or at least about 1 millimetre H₂O.

The hollow tubular element may comprise one or more hollow tubular segments. Preferably, the hollow tubular element consists of one (single) hollow tubular segment. Preferably, the hollow tubular element consists of a continuous hollow tubular segment. A hollow tubular segment may comprise any of the features described in the present disclosure in relation to the hollow tubular element.

As will be described within the present disclosure, the aerosol-generating article may comprise a ventilation zone at a location along the aerosol-generating article. In the context of a ventilation zone, the term ‘location’ preferably refers to a longitudinal location, unless otherwise specified. The aerosol-generating article may comprise a ventilation zone at a location along the downstream section. The aerosol-generating article may comprise a ventilation zone at a location along the downstream air channelling element. In other words, a ventilation zone may be provided at a longitudinal location along the downstream air channelling element. A ventilation zone may overlie the downstream air channelling element.

The aerosol-generating article may comprise a ventilation zone at a location along the hollow tubular element. Such a, or any, ventilation zone may extend through the peripheral wall of the hollow tubular element. As such, fluid communication is established between the flow channel internally defined by the hollow tubular element and the outer environment (in other words, the exterior of the aerosol-generating article). A ventilation zone may be provided at a location along the downstream air channelling element. Such a ventilation zone may extend through any wrapper or wrappers circumscribing an air channelling element. Such a ventilation zone provided along an air channelling element may establish a fluid communication between the exterior of the aerosol-generating article and the one or more outer air passageways (or grooves). Such a ventilation zone provided along an air channelling element may establish a fluid communication from the exterior of the aerosol-generating article to the one or more outer air passageways (or grooves).

The length of the hollow tubular element may be at least about 8 mm. The length of the hollow tubular element may be at least about 10 mm. The length of the hollow tubular element may be at least about 15 mm. The length of the hollow tubular element may be at least about 19 mm.

The length of the hollow tubular element may be less or equal than about 30 mm. The length of the hollow tubular element may be less or equal than about 25 mm. The length of the hollow tubular element may be less or equal than about 23 mm.

The length of the hollow tubular element may be between about 8 mm and 30 mm. The length of the hollow tubular element may be between about 10 mm and 30 mm. The length of the hollow tubular element may be between about 15 mm and 25 mm. The length of the hollow tubular element may be between about 19 mm and 23 mm.

A relatively long hollow tubular element provides and defines a relatively long internal cavity within the aerosol-generating article and downstream of the rod of aerosol-generating substrate. As discussed in the present disclosure, providing an empty cavity downstream (preferably, immediately downstream) of the aerosol-generating substrate enhances the nucleation of aerosol particles generated by the substrate. Providing a relatively long cavity maximises such nucleation benefits, thereby improving aerosol formation and cooling. Providing such a hollow tubular element downstream of a downstream air channelling element further enhances the aerosol formation and cooling benefits provided by an air channelling element itself.

The thickness of a peripheral wall (in other words, the wall thickness) of the hollow tubular element may be at least about 100 micrometres. The wall thickness of the hollow tubular element may be at least about 150 micrometres. The wall thickness of the hollow tubular element may be at least about 200 micrometres, preferably at least about 250 micrometres and even more preferably at least about 500 micrometres (or 0.5 mm).

The wall thickness of the hollow tubular element may be less than or equal to about 2 millimetres, preferably less than or equal to about 1.5 millimetres and even more preferably less than or equal to about 1 .25 mm. The wall thickness of the hollow tubular element may be less than or equal to about 1 millimetre. The wall thickness of the hollow tubular element may be less than or equal to about 500 micrometres.

The wall thickness of the hollow tubular element may between about 100 micrometres and about 2 millimetres, preferably between about 150 micrometres and about 1.5 millimetres, even more preferably between about 200 micrometres and about 1 .25 millimetres. The wall thickness of the hollow tubular element may preferably be about 250 micrometres (0.25 mm).

At the same time, keeping the thickness of the peripheral wall of the hollow tubular segment relatively low ensures that the overall internal volume of the hollow tubular segment - which is made available for the aerosol to begin the nucleation process as soon as the aerosol components leave the rod of aerosol-generating substrate - and the cross-sectional surface area of the hollow tubular segment are effectively maximised, whilst at the same time ensuring that the hollow tubular segment has the necessary structural strength to prevent a collapse of the aerosolgenerating article as well as to provide some support to the rod of aerosol-generating substrate, and that the RTD of the hollow tubular segment is minimised. Greater values of cross-sectional surface area of the cavity of the hollow tubular segment are understood to be associated with a reduced speed of the aerosol stream travelling along the aerosol-generating article, which is also expected to favour aerosol nucleation. Further, it would appear that by utilising a hollow tubular segment having a relatively low thickness, it is possible to substantially prevent diffusion of the ventilation air prior to its contacting and mixing with the stream of aerosol, which is also understood to further favour nucleation phenomena. In practice, by providing a more controllably localised cooling of the stream of volatilised species, it is possible to enhance the effect of cooling on the formation of new aerosol particles.

The hollow tubular element preferably has an outer diameter that is approximately equal to the outer diameter of the rod of aerosol-generating substrate and to the outer diameter of the aerosol-generating article. The hollow tubular element may have an outer diameter of between 5 millimetres and 12 millimetres, for example of between 5 millimetres and 10 millimetres or of between 6 millimetres and 8 millimetres. The hollow tubular element may preferably have an external diameter of 7.2 millimetres plus or minus 10 percent.

The hollow tubular element may have an internal diameter. Preferably, the hollow tubular element may have a constant internal diameter along a length of the hollow tubular element. However, the internal diameter of the hollow tubular element may vary along the length of the hollow tubular element.

The hollow tubular element may have an internal diameter of at least about 2 millimetres. For example, the hollow tubular element may have an internal diameter of at least about 4 millimetres, at least about 5 millimetres, or at least about 7 millimetres.

The provision of a hollow tubular element having an internal diameter as set out above may advantageously provide sufficient rigidity and strength to the hollow tubular element.

The hollow tubular element may have an internal diameter of no more than about 10 millimetres. For example, the hollow tubular element may have an internal diameter of no more than about 9 millimetres, no more than about 8 millimetres, or no more than about 7.5 millimetres.

The provision of a hollow tubular element having an internal diameter as set out above may advantageously reduce the resistance to draw of the hollow tubular segment.

The hollow tubular element may have an internal diameter of between about 2 millimetres and about 10 millimetres, between about 4 millimetres and about 9 millimetres, between about 5 millimetres and about 8 millimetres, or between about 6 millimetres and about 7.5 millimetres.

The hollow tubular element may have an external diameter of about 7.1 or 7.2 mm. The hollow tubular element may have an internal diameter of about 6.7 millimetres.

The hollow tubular segment may comprise a paper-based material. The hollow tubular segment may comprise at least one layer of paper. The paper may be very rigid paper. The paper may be crimped paper, such as crimped heat resistant paper or crimped parchment paper.

Preferably, the hollow tubular element may comprise cardboard. The hollow tubular element may be a cardboard tube. The hollow tubular element may be formed from cardboard. Advantageously, cardboard is a cost-effective material that provides a balance between being deformable in order to provide ease of insertion of the article into an aerosol-generating device and being sufficiently stiff to provide suitable engagement of the article with the interior of the device. A cardboard tube may therefore provide suitable resistance to deformation or compression during use.

The hollow tubular segment may be paper tube. The hollow tubular segment may be a tube formed from spirally wound paper. The hollow tubular segment may be formed from a plurality of layers of the paper. The paper may have a basis weight of at least about 50 grams per square meter, at least about 60 grams per square meter, at least about 70 grams per square meter, or at least about 90 grams per square meter.

The hollow tubular segment may comprise a polymeric material. For example, the hollow tubular segment may comprise a polymeric film. The polymeric film may comprise a cellulosic film. The hollow tubular segment may comprise low density polyethylene (LDPE) or polyhydroxyalkanoate (PHA) fibres. The hollow tube may comprise cellulose acetate tow.

As set out above, the aerosol-generating article according to the present invention comprises a downstream section comprising a hollow tubular element provided downstream of the rod of aerosol-generating substrate and abutting a downstream end of the rod of aerosolgenerating substrate. Additionally, the aerosol-generating article according to the present invention comprises a ventilation zone at a location along the hollow tubular element. The aerosol-generating article according to the present invention may comprise a ventilation zone at a location along the downstream air channelling element.

As such, a ventilated cavity is provided downstream of the rod of aerosol-generating substrate, either in the form of a ventilated groove or external air passageway of the air channelling element or in the form of a ventilated internal cavity of the hollow tubular element. This provides several potential technical benefits.

First of all, the inventors have found that one such ventilated hollow tubular element or air channelling element provides a particularly efficient cooling of the aerosol. Thus, a satisfactory cooling of the aerosol can be achieved even by means of a relatively short downstream section. This is especially desirable as it enables the provision of an aerosol-generating article wherein an aerosol-generating substrate (and particularly a tobacco-containing one) is heated rather than combusted that combines a satisfactory aerosol delivery with an efficient cooling of the aerosol down to temperatures that are desirable for the consumer.

Secondly, the inventors have surprisingly found that such rapid cooling of the volatile species released upon heating the aerosol-generating substrate promotes enhances nucleation of aerosol particles. This effect is felt particularly when, as will be described in more detail below, the ventilation zone is arranged at a precisely defined location downstream of the rod of aerosolgenerating substrate. In effect, the inventors have found that the favourable effect of the enhanced nucleation is capable of significantly countering potentially less desirable effects of the dilution induced by the introduction of ventilation air.

Similarly, a ventilation zone may be provide similar benefits by being located along a downstream air channelling element and providing ventilation at such a location.

The ventilation zone may typically comprise a plurality of perforations through the peripheral wall of the hollow tubular element. The ventilation zone may typically comprise a plurality of perforations extending through the peripheral wall of the hollow tubular element. The ventilation zone may extend through material of an air channelling element to provide fluid communication between any outer air passageways (which may not be grooves provided on the outer surface of the air channelling element) and the exterior of the aerosol-generating article. As such, the ventilation zone may comprise a plurality of perforations extending through material of the air channelling element to provide fluid communication between any outer air passageways and the exterior of the aerosol-generating article.

The ventilation zone may comprise a plurality of perforations through the wrapper surrounding an air channelling element. The ventilation zone may comprise a plurality of perforations extending through a wrapper surrounding an air channelling element. The ventilation zone may comprise a plurality of perforations extending through material of an air channelling element to provide fluid communication with the one or more outer air passageways. Equivalent benefits to a ventilation zone provided along a hollow tubular element are achieved with a ventilation zone being provided along a downstream air channelling element, but in the context of an aerosol-generating article that may not comprise a hollow tubular element. A ventilation zone along an air channelling element may provide fluid communication with the outer air passageways or grooves of an air channelling element, where an aerosol stream may be arranged to travel. Such a ventilation zone provided along an air channelling element may establish a fluid communication between the exterior of the aerosol-generating article and the one or more outer air passageways. Such a ventilation zone provided along an air channelling element may establish a fluid communication from the exterior of the aerosol-generating article to the one or more outer air passageways. Such a ventilation zone may extend through material of an air channelling element to provide fluid communication between any outer air passageways (which may not be grooves provided on the outer surface of the air channelling element) and the exterior of the aerosol-generating article.

Preferably, the ventilation zone comprises at least one circumferential row of perforations. The ventilation zone may comprise two circumferential rows of perforations. For example, the perforations may be formed online during manufacturing of the aerosol-generating article. Preferably, each circumferential row of perforations comprises from 8 to 30 perforations.

An aerosol-generating article in accordance with the present invention may have a ventilation level of at least about 2 percent.

The term “ventilation level” is used throughout the present specification to denote a volume ratio between of the airflow admitted into the aerosol-generating article via the ventilation zone (ventilation airflow) and the sum of the aerosol airflow and the ventilation airflow. The greater the ventilation level, the higher the dilution of the aerosol flow delivered to the consumer. The aerosolgenerating article preferably has a ventilation level of at least 5 percent, more preferably at least 10 percent, even more preferably at least 12 percent or at least 15 percent.

An aerosol-generating article in accordance with the present invention may have a ventilation level of up to about 90 percent. Preferably, an aerosol-generating article in accordance with the present invention has a ventilation level of less than or equal to 80 percent, more preferably less than or equal to 70 percent, even more preferably less than or equal to 60 percent, most preferably less than or equal to 50 percent.

Without wishing to be bound by theory, the inventors have found that the temperature drop caused by the admission of cooler, external air into the hollow tubular element or downstream air channelling element (in particular, the outer air passageways or grooves thereof) via the ventilation zone may have an advantageous effect on the nucleation and growth of aerosol particles.

Formation of an aerosol from a gaseous mixture containing various chemical species depends on a delicate interplay between nucleation, evaporation, and condensation, as well as coalescence, all the while accounting for variations in vapour concentration, temperature, and velocity fields. The so-called classical nucleation theory is based on the assumption that a fraction of the molecules in the gas phase are large enough to stay coherent for long times with sufficient probability (for example, a probability of one half). These molecules represent some kind of a critical, threshold molecule clusters among transient molecular aggregates, meaning that, on average, smaller molecule clusters are likely to disintegrate rather quickly into the gas phase, while larger clusters are, on average, likely to grow. Such critical cluster is identified as the key nucleation core from which droplets are expected to grow due to condensation of molecules from the vapour. It is assumed that virgin droplets that just nucleated emerge with a certain original diameter, and then may grow by several orders of magnitude. This is facilitated and may be enhanced by rapid cooling of the surrounding vapour, which induces condensation. In this connection, it helps to bear in mind that evaporation and condensation are two sides of one same mechanism, namely gas-liquid mass transfer. While evaporation relates to net mass transfer from the liquid droplets to the gas phase, condensation is net mass transfer from the gas phase to the droplet phase. Evaporation (or condensation) will make the droplets shrink (or grow), but it will not change the number of droplets.

In this scenario, which may be further complicated by coalescence phenomena, the temperature and rate of cooling can play a critical role in determining how the system responds. In general, different cooling rates may lead to significantly different temporal behaviours as concerns the formation of the liquid phase (droplets), because the nucleation process is typically nonlinear. Without wishing to be bound by theory, it is hypothesised that cooling can cause a rapid increase in the number concentration of droplets, which is followed by a strong, short-lived increase in this growth (nucleation burst). This nucleation burst would appear to be more significant at lower temperatures. Further, it would appear that higher cooling rates may favour an earlier onset of nucleation. By contrast, a reduction of the cooling rate would appear to have a favourable effect on the final size that the aerosol droplets ultimately reach. Therefore, the rapid cooling induced by the admission of external air into the hollow tubular element or the downstream air channelling element (in particular, the outer air passageways or grooves thereof) via the ventilation zone can be favourably used to favour nucleation and growth of aerosol droplets. However, at the same time, the admission of external air into the hollow tubular element or the downstream air channelling element (in particular, the outer air passageways or grooves thereof) has the immediate drawback of diluting the aerosol stream delivered to the consumer.

The inventors have surprisingly found how the favourable effect of enhanced nucleation promoted by the rapid cooling induced by the introduction of ventilation air into the article is capable of significantly countering the less desirable effects of dilution. As such, satisfactory values of aerosol delivery are consistently achieved with aerosol-generating articles in accordance with the invention.

The inventors have also surprisingly found that the diluting effect on the aerosol - which can be assessed by measuring, in particular, the effect on the delivery of aerosol former (for example, glycerol) included in the aerosol-generating substrate - is advantageously minimised when the ventilation level is within the ranges described above.

In particular, ventilation levels between 10 percent and 20 percent, and even more preferably between 12 and 18 percent, have been found to lead to particularly satisfactory values of glycerol delivery.

This is particularly advantageous with “short” aerosol-generating articles, such as ones wherein a length of the rod of aerosol-generating substrate is less than about 40 millimetres, preferably less than 30 millimetres, even more preferably less than 25 millimetres, and particularly preferably less than 20 millimetres, or wherein an overall length of the aerosol-generating article is less than about 70 millimetres, preferably less than about 60 millimetres, even more preferably less than 50 millimetres. As will be appreciated, in such aerosol-generating articles, there is typically little time and space for the aerosol to form and for the particulate phase of the aerosol to become available for delivery to the consumer, and so the benefits of the enhanced nucleation described above are felt in particularly significant fashion.

A distance between the ventilation zone and a downstream end of the aerosol-generating article may be at least 10 millimetres. Preferably, a distance between the ventilation zone and a downstream end of the aerosol-generating article is at least 12 millimetres. More preferably, a distance between the ventilation zone and a downstream end of the aerosol-generating article is at least 15 millimetres.

A distance between the ventilation zone and a downstream end of the aerosol-generating article is preferably less than or equal to 21 millimetres. More preferably, a distance between the ventilation zone and a downstream end of the aerosol-generating article is less than or equal to 19 millimetres. Even more preferably, a distance between the ventilation zone and a downstream end of the aerosol-generating article is less than or equal to 17 millimetres.

A distance between the ventilation zone and a downstream end of the aerosol-generating article may be from 10 millimetres to 21 millimetres, preferably from 12 millimetres to 21 millimetres, more preferably from 15 millimetres to 21 millimetres. A distance between the ventilation zone and a downstream end of the aerosol-generating article may be from 10 millimetres to 19 millimetres, preferably from 12 millimetres to 19 millimetres, more preferably from 15 millimetres to 19 millimetres. A distance between the ventilation zone and a downstream end of the aerosol-generating article may be from 10 millimetres to 17 millimetres, preferably from 12 millimetres to 17 millimetres, more preferably from 15 millimetres to 17 millimetres.

The ventilation zone may be located along the downstream air channelling element. A distance between the ventilation zone and a downstream end of the downstream air channelling element is preferably less than or equal to 10 millimetres. A distance between the ventilation zone and a downstream end of the downstream air channelling element is preferably less than or equal to 7 millimetres. A distance between the ventilation zone and a downstream end of the downstream air channelling element is preferably less than or equal to 5 millimetres. A distance between the ventilation zone and a downstream end of the downstream air channelling element is preferably less than or equal to 3 millimetres. A ventilation zone is preferably located along the downstream half of the downstream air channelling element.

Positioning the ventilation zone at a distance from a downstream end of the aerosolgenerating article within the ranges described above has the benefit of generally ensuring that, during use, when the aerosol-generating article is partially received within the heating device, a portion of the aerosol-generating article extending outside of the heating device is long enough for the consumer to comfortably hold the article between their lips. At the same time, evidence suggests that a length of the portion of the aerosol-generating article extending outside of the heating device were greater, it may become easy to inadvertently and undesirably bend the aerosol-generating article, and this may impair aerosol delivery or in general the intended use of the aerosol-generating article.

As discussed in the present disclosure, the downstream section may comprise a mouthpiece element. The mouthpiece element may extend from a downstream end of the downstream section. The mouthpiece element may be located at the downstream end of the aerosol-generating article. The downstream end of the mouthpiece element may define the downstream end of the aerosol-generating article. The mouthpiece element may abut an air channelling element. As such, a hollow tubular element may not be provided.

The mouthpiece element may be provided downstream of the rod of aerosol-generating substrate. The mouthpiece element may extend all the way to a mouth end of the aerosolgenerating article. The mouthpiece element may comprise at least one mouthpiece filter segment formed of a fibrous filtration material. The mouthpiece element may be located downstream of a hollow tubular element, which is described above. The mouthpiece element may extend between the hollow tubular element and the downstream end of the aerosol-generating article.

Parameters or characteristics described in relation to the mouthpiece element as a whole may equally be applied to a mouthpiece filter segment of the mouthpiece element.

The fibrous filtration material may be for filtering the aerosol that is generated from the aerosol-generating substrate. Suitable fibrous filtration materials would be known to the skilled person. Particularly preferably, the at least one mouthpiece filter segment comprises a cellulose acetate filter segment formed of cellulose acetate tow.

The mouthpiece element may consist of a single mouthpiece filter segment. The mouthpiece element may include two or more mouthpiece filter segments axially aligned in an abutting end to end relationship with each other.

The downstream section may comprise a mouth end cavity at the downstream end, downstream of the mouthpiece element as described above. The mouth end cavity may be defined by a further hollow tubular element provided at the downstream end of the mouthpiece. The mouth end cavity may be defined by an outer wrapper of the aerosol-generating article, wherein the outer wrapper extends in a downstream direction from (or past) the mouthpiece element.

The mouthpiece element may optionally comprise a flavourant, which may be provided in any suitable form. For example, the mouthpiece element may comprise one or more capsules, beads or granules of a flavourant, or one or more flavour loaded threads or filaments.

Preferably, the mouthpiece element, or mouthpiece filter segment thereof, has a low particulate filtration efficiency.

Preferably, the mouthpiece element is circumscribed by a plug wrap. Preferably, the mouthpiece element is unventilated such that air does not enter the aerosol-generating article along the mouthpiece element.

The mouthpiece element is preferably connected to one or more of the adjacent upstream components of the aerosol-generating article by means of a tipping wrapper.

The mouthpiece element preferably has an external diameter that is approximately equal to the external diameter of the aerosol-generating article. The diameter of a mouthpiece element (or mouthpiece filter segment) may be substantially the same as the outer diameter of the hollow tubular element. As mentioned in the present disclosure, the outer diameter of the hollow tubular element may be about 7.2mm, plus or minus 10 percent.

The diameter of the mouthpiece element may be between about 5 mm and about 10 mm. The diameter of the mouthpiece element may be between about 6 mm and about 8 mm. The diameter of the mouthpiece element may be between about 7 mm and about 8 mm. The diameter of the mouthpiece element may be about 7.2 mm, plus or minus 10 percent. The diameter of the mouthpiece element may be about 7.25 mm, plus or minus 10 percent.

Unless otherwise specified, the resistance to draw (RTD) of a component or the aerosolgenerating article is measured in accordance with ISO 6565-2015. The RTD refers the pressure required to force air through the full length of a component. The terms “pressure drop” or “draw resistance” of a component or article may also refer to the “resistance to draw”. Such terms generally refer to the measurements in accordance with ISO 6565-2015 are normally carried out at under test at a volumetric flow rate of about 17.5 millilitres per second at the output or downstream end of the measured component at a temperature of about 22 degrees Celsius, a pressure of about 101 kPa (about 760 Torr) and a relative humidity of about 60%.

The resistance to draw (RTD) of the downstream section may be at least about 0 mm H₂O. The RTD of the downstream section may be at least about 3 mm H₂O. The RTD of the downstream section may be at least about 6 mm H₂O.

The RTD of the downstream section may be no greater than about 12 mm H₂O. The RTD of the downstream section may be no greater than about 1 1 mm H₂O. The RTD of the downstream section may be no greater than about 10 mm H₂O.

The resistance to draw (RTD) of the mouthpiece element may be at least about 0 mm H₂O. The RTD of the mouthpiece element may be at least about 3 mm H₂O. The RTD of the mouthpiece element may be at least about 6 mm H₂O.

The RTD of the mouthpiece element may be no greater than about 12 mm H₂O. The RTD of the mouthpiece element may be no greater than about 1 1 mm H₂O. The RTD of the mouthpiece element may be no greater than about 10 mm H₂O.

As mentioned above, the mouthpiece element, or mouthpiece filter segment, may be formed of a fibrous material. The mouthpiece element may be formed of a porous material. The mouthpiece element may be formed of a biodegradable material. The mouthpiece element may be formed of a cellulose material, such as cellulose acetate. For example, a mouthpiece element may be formed from a bundle of cellulose acetate fibres having a denier per filament between about 10 and about 15. For example, a mouthpiece element formed from relatively low density cellulose acetate tow, such as cellulose acetate tow comprising fibres of about 12 denier per filament.

The mouthpiece element may be formed of a polylactic acid based material. The mouthpiece element may be formed of a bioplastic material, preferably a starch-based bioplastic material. The mouthpiece element may be made by injection moulding or by extrusion. Bioplastic-based materials are advantageous because they are able to provide mouthpiece element structures which are simple and cheap to manufacture with a particular and complex cross-sectional profile, which may comprise a plurality of relatively large air flow channels extending through the mouthpiece element material, that provides suitable RTD characteristics. The mouthpiece element may be formed from a sheet of suitable material that has been crimped, pleated, gathered, woven or folded into an element that defines a plurality of longitudinally extending channels. Such sheet of suitable material may be formed of paper, cardboard, a polymer, such as polylactic acid, or any other cellulose-based, paper-based material or bioplastic-based material. A cross-sectional profile of such a mouthpiece element may show the channels as being randomly oriented.

The mouthpiece element may be formed in any other suitable manner. For example, the mouthpiece element may be formed from a bundle of longitudinally extending tubes. The longitudinally extending tubes may be formed from polylactic acid. The mouthpiece element may be formed by extrusion, moulding, lamination, injection, or shredding of a suitable material. Thus, it is preferred that there is a low-pressure drop (or RTD) from an upstream end of the mouthpiece element to a downstream end of the mouthpiece element.

The length of the mouthpiece element may be at least about 3 mm. The length of the mouthpiece element may be at least about 5 mm. The length of the mouthpiece element may equal to or less than about 15 mm. The length of the mouthpiece element may be equal to or less than about 11 mm. The length of the mouthpiece element may be between about 3 mm and about 15 mm. The length of the mouthpiece element may be between about 5 millimetres and about 1 1 millimetres.

Preferably, the length of the mouthpiece element may be about 7 mm. Preferably, the length of the mouthpiece element may be about 8 mm. Preferably, the length of the mouthpiece element may be about 9 mm.

The aerosol-generating article may have an overall length from about 35 millimetres to about 100 millimetres.

Preferably, an overall length of an aerosol-generating article in accordance with the invention is at least about 35 millimetres. An overall length of an aerosol-generating article in accordance with the invention is at least about 38 millimetres. More preferably, an overall length of an aerosol-generating article in accordance with the invention is at least about 40 millimetres. Even more preferably, an overall length of an aerosol-generating article in accordance with the invention is at least about 42 millimetres.

An overall length of an aerosol-generating article in accordance with the invention is preferably less than or equal to 70 millimetres. More preferably, an overall length of an aerosolgenerating article in accordance with the invention is preferably less than or equal to 60 millimetres. Even more preferably, an overall length of an aerosol-generating article in accordance with the invention is preferably less than or equal to 50 millimetres.

An overall length of the aerosol-generating article is preferably from about 38 millimetres to about 70 millimetres, more preferably from about 40 millimetres to about 70 millimetres, even more preferably from about 42 millimetres to about 70 millimetres. An overall length of the aerosol-generating article is preferably from about 38 millimetres to about 60 millimetres, more preferably from about 40 millimetres to about 60 millimetres, even more preferably from about 42 millimetres to about 60 millimetres. An overall length of the aerosol-generating article is preferably from about 38 millimetres to about 50 millimetres, more preferably from about 40 millimetres to about 50 millimetres, even more preferably from about 42 millimetres to about 50 millimetres. An overall length of the aerosol-generating article may be about 45 millimetres.

The aerosol-generating article has an external diameter of at least 5 millimetres. Preferably, the aerosol-generating article has an external diameter of at least 6 millimetres. More preferably, the aerosol-generating article has an external diameter of at least 7 millimetres.

Preferably, the aerosol-generating article has an external diameter of less than or equal to about 12 millimetres. More preferably, the aerosol-generating article has an external diameter of less than or equal to about 10 millimetres. Even more preferably, the aerosol-generating article has an external diameter of less than or equal to about 8 millimetres.

The aerosol-generating article may have an external diameter from about 5 millimetres to about 12 millimetres, preferably from about 6 millimetres to about 12 millimetres, more preferably from about 7 millimetres to about 12 millimetres. The aerosol-generating article may have an external diameter from about 5 millimetres to about 10 millimetres, preferably from about 6 millimetres to about 10 millimetres, more preferably from about 7 millimetres to about 10 millimetres. The aerosol-generating article may have an external diameter from about 5 millimetres to about 8 millimetres, preferably from about 6 millimetres to about 8 millimetres, more preferably from about 7 millimetres to about 8 millimetres.

The external diameter of the aerosol-generating article may be substantially constant over the whole length of the article. As an alternative, different portions of the aerosol-generating article may have different external diameters.

An aerosol-generating article in accordance with the present invention may comprise a rod of aerosol-generating substrate and a downstream section located downstream of the rod of aerosol-generating substrate. The downstream section may comprise a downstream air channelling element and a mouthpiece element. The downstream air channelling element may be located between the rod of aerosol-generating substrate and the mouthpiece element. The downstream air channelling element may be in accordance with an air channelling element described in the present disclosure. All components may be assembled in an axial, sequential, and abutting manner within a wrapper of the aerosol-generating article. The aerosol-generating article may comprise a ventilation zone provided at a location along the downstream air channelling element.

An aerosol-generating article in accordance with the present invention may comprise a rod of aerosol-generating substrate and a downstream section located downstream of the rod of aerosol-generating substrate. The downstream section may comprise a downstream air channelling element and a mouthpiece element. The downstream air channelling element may be located between the rod of aerosol-generating substrate and the mouthpiece element. The downstream air channelling element may be in accordance with an air channelling element described in the present disclosure. All components may be assembled in an axial, sequential, and abutting manner within a wrapper of the aerosol-generating article. The downstream section may also comprise a hollow tubular element located between the downstream air channelling element and the mouthpiece element. The aerosol-generating article may also comprise an upstream section located upstream of the rod of aerosol-generating substrate. The upstream section comprises an upstream element. The upstream element may comprise a plug element or a hollow tubular element, as described in the present disclosure. The aerosol-generating article may comprise a ventilation zone provided at a location along the hollow tubular element or the downstream air channelling element.

An aerosol-generating article in accordance with the present invention may comprise a rod of aerosol-generating substrate, a downstream section located downstream of the rod of aerosol-generating substrate and an upstream section located upstream of the rod of aerosolgenerating substrate. The downstream section may comprise a hollow tubular element and a mouthpiece element. The upstream section may comprise an upstream air channelling element. The hollow tubular element may be located between the rod of aerosol-generating substrate and the mouthpiece element. The upstream air channelling element may be in accordance with an air channelling element described in the present disclosure. All components may be assembled in an axial, sequential, and abutting manner within a wrapper of the aerosol-generating article. The downstream section may also comprise a downstream air channelling element located between the rod of aerosol-generating substrate and the hollow tubular element. The aerosolgenerating article may comprise a ventilation zone provided at a location along the hollow tubular element or the downstream air channelling element.

An aerosol-generating article in accordance with the present invention may comprise a rod of aerosol-generating substrate, a downstream section located downstream of the rod of aerosol-generating substrate and an upstream section located upstream of the rod of aerosolgenerating substrate. The downstream section may comprise a downstream air channelling element and a mouthpiece element. The upstream section may comprise an upstream air channelling element. The downstream air channelling element may be located between the rod of aerosol-generating substrate and the mouthpiece element. The upstream air channelling element and the downstream air channelling element may be in accordance with an air channelling element described in the present disclosure. All components may be assembled in an axial, sequential, and abutting manner within a wrapper of the aerosol-generating article. The downstream section may also comprise a hollow tubular element located between the downstream air channelling element and the mouthpiece element. The aerosol-generating article may comprise a ventilation zone provided at a location along the hollow tubular element or the downstream air channelling element.

As discussed above, the present disclosure also relates to an aerosol-generating system comprising an aerosol-generating device having a distal end and a mouth end. The aerosolgenerating device may comprise a body. The body or housing of the aerosol-generating device may define a device cavity for removably receiving the aerosol-generating article at the mouth end of the device. The aerosol-generating device may comprise a heating element or heater for heating the aerosol-generating substrate when the aerosol-generating article is received within the device cavity.

The device cavity may be referred to as the heating chamber of the aerosol-generating device. The device cavity may extend between a distal end and a mouth, or proximal, end. The distal end of the device cavity may be a closed end and the mouth, or proximal, end of the device cavity may be an open end. An aerosol-generating article may be inserted into the device cavity, or heating chamber, via the open end of the device cavity. The device cavity may be cylindrical in shape so as to conform to the same shape of an aerosol-generating article.

The expression “received within” may refer to the fact that a component or element is fully or partially received within another component or element. For example, the expression “aerosolgenerating article is received within the device cavity” refers to the aerosol-generating article being fully or partially received within the device cavity of the aerosol-generating article. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may abut the distal end of the device cavity. When the aerosol-generating article is received within the device cavity, the aerosol-generating article may be in substantial proximity to the distal end of the device cavity. The distal end of the device cavity may be defined by an end-wall.

The length of the device cavity may be between about 10 mm and about 50 mm. The length of the device cavity may be between about 20 mm and about 40 mm. The length of the device cavity may be between about 25 mm and about 30 mm.

The length of the device cavity (or heating chamber) may be the same as or greater than the length of the rod of the aerosol-generating substrate. The length of the device cavity may be the same as or greater than the combined length of the upstream section or element and rod of aerosol-generating substrate. The length of the device cavity may be such that the downstream section or a portion thereof is configured to protrude from the device cavity, when the aerosolgenerating article received within the device cavity. The length of the device cavity may be such that a portion of the downstream section (such as the hollow tubular element or mouthpiece element) is configured to protrude from the device cavity, when the aerosol-generating article received within the device cavity. The length of the device cavity may be such that a portion of the downstream section (such as the hollow tubular element or mouthpiece element) is configured to be received within the device cavity, when the aerosol-generating article received within the device cavity.

At least 25 percent of the length of the downstream section may be inserted or received within the device cavity, when the aerosol-generating article is received within the device. At least 30 percent of the length of the downstream section may be inserted or received within the device cavity, when the aerosol-generating article is received within the device.

Optimising the amount or length of the article that is inserted into the aerosol-generating device may enhance the article’s resistance to inadvertently falling out during use. Particularly, during the heating of the aerosol-generating substrate, the substrate may shrink such that its external diameter may have reduced, thereby reducing the extent to which the inserted portion of the article inserted into the device can frictionally engage with the device cavity. The inserted portion of the article, or the portion of the article configured to be received within the device cavity, may be the same length as the device cavity.

Preferably, the length of the device cavity is between about 25 mm and about 29 mm. More preferably, the length of the device cavity is between about 26 mm and about 29 mm. Even more preferably, the length of the device cavity is about 27 mm or about 28 mm.

Preferably, the combined length of the upstream section (or element) and the inserted portion of the downstream section is equivalent to between about 80 percent and about 120 percent of the length of the protruding portion of the aerosol-generating article. The inserted portion of the downstream section or hollow tubular element or aerosol-generating article refers to the portion of the downstream section or hollow tubular element or aerosol-generating article that is configured to be positioned within the device cavity when the aerosol-generating article is received therein. The protruding portion of the aerosol-generating article refers to the article that is configured to be positioned outside of the device cavity, or protrude from the device, when the aerosol-generating article is received therein. The inventors have found that such a relationship minimises the risk of inadvertent exit of the article from the device during use, particularly following potential shrinkage of the article during use. The portion of the aerosol-generating article configured to be inserted into the device is preferably longer than the portion of the aerosolgenerating article configured to be protruding from the device, when the aerosol-generating article is received within the aerosol-generating device.

A diameter of the device cavity may be between about 4 mm and about 10 mm. A diameter of the device cavity may be between about 5 mm and about 9 mm. A diameter of the device cavity may be between about 6 mm and about 8 mm. A diameter of the device cavity may be between about 7 mm and about 8 mm. A diameter of the device cavity may be between about 7 mm and about 7.5 mm.

A diameter of the device cavity may be substantially the same as or greater than a diameter of the aerosol-generating article. A diameter of the device cavity may be the same as a diameter of the aerosol-generating article in order to establish a tight fit with the aerosolgenerating article.

The device cavity may be configured to establish a tight fit with an aerosol-generating article received within the device cavity. Tight fit may refer to a snug or interference fit. The aerosol-generating device may comprise a peripheral wall. Such a peripheral wall may define the device cavity, or heating chamber. The peripheral wall defining the device cavity may be configured to engage with an aerosol-generating article received within the device cavity in a tight fit manner, so that there is substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article when received within the device.

Such a tight fit may establish an airtight fit or configuration between the device cavity and an aerosol-generating article received therein.

With such an airtight configuration, there would be substantially no gap or empty space between the peripheral wall defining the device cavity and the aerosol-generating article for air to flow through.

The tight fit with an aerosol-generating article may be established along the entire length of the device cavity or along a portion of the length of the device cavity.

The aerosol-generating device may comprise an air-flow channel extending between a channel inlet and a channel outlet. The air-flow channel may be configured to establish a fluid communication between the interior of the device cavity and the exterior of the aerosol-generating device. The air-flow channel of the aerosol-generating device may be defined within the housing of the aerosol-generating device to enable fluid communication between the interior of the device cavity and the exterior of the aerosol-generating device. When an aerosol-generating article is received within the device cavity, the air-flow channel may be configured to provide air flow into the article in order to deliver generated aerosol to a user drawing from the mouth end of the article.

The air-flow channel of the aerosol-generating device may be defined within, or by, the peripheral wall of the housing of the aerosol-generating device. In other words, the air-flow channel of the aerosol-generating device may be defined within the thickness of the peripheral wall or by the inner surface of the peripheral wall, or a combination of both. The air-flow channel may partially be defined by the inner surface of the peripheral wall and may be partially defined within the thickness of the peripheral wall. The inner surface of the peripheral wall defines a peripheral boundary of the device cavity.

The air-flow channel of the aerosol-generating device may extend from an inlet located at the mouth end, or proximal end, of the aerosol-generating device to an outlet located away from mouth end of the device. The air-flow channel may extend along a direction parallel to the longitudinal axis of the aerosol-generating device.

The heater may be any suitable type of heater. Preferably, in the present invention, the heater is an external heater. Preferably, the heater may externally heat the aerosol-generating article when received within the aerosol-generating device. Such an external heater may circumscribe the aerosolgenerating article when inserted in or received within the aerosol-generating device.

The heater may be arranged to heat the outer surface of the aerosol-generating substrate. The heater may be arranged for insertion into an aerosol-generating substrate when the aerosolgenerating substrate is received within the cavity. The heater may be positioned within the device cavity, or heating chamber.

The heater may comprise at least one heating element. The at least one heating element may be any suitable type of heating element. The device may comprise only one heating element. The device may comprise a plurality of heating elements. The heater may comprise at least one resistive heating element. Preferably, the heater comprises a plurality of resistive heating elements. Preferably, the resistive heating elements are electrically connected in a parallel arrangement. Advantageously, providing a plurality of resistive heating elements electrically connected in a parallel arrangement may facilitate the delivery of a desired electrical power to the heater while reducing or minimising the voltage required to provide the desired electrical power. Advantageously, reducing or minimising the voltage required to operate the heater may facilitate reducing or minimising the physical size of the power supply.

Suitable materials for forming the at least one resistive heating element include but are not limited to: semiconductors such as doped ceramics, electrically ‘conductive’ ceramics (such as, for example, molybdenum disilicide), carbon, graphite, metals, metal alloys and composite materials made of a ceramic material and a metallic material. Such composite materials may comprise doped or undoped ceramics. Examples of suitable doped ceramics include doped silicon carbides. Examples of suitable metals include titanium, zirconium, tantalum and metals from the platinum group. Examples of suitable metal alloys include stainless steel, nickel-, cobalt- , chromium-, aluminium- titanium- zirconium-, hafnium-, niobium-, molybdenum-, tantalum-, tungsten-, tin-, gallium-, manganese- and iron-containing alloys, and super-alloys based on nickel, iron, cobalt, stainless steel, Timetai® and iron-manganese-aluminium based alloys.

The at least one resistive heating element may comprise one or more stamped portions of electrically resistive material, such as stainless steel. The at least one resistive heating element may comprise a heating wire or filament, for example a Ni-Cr (Nickel-Chromium), platinum, tungsten or alloy wire.

The at least one heating element may comprise an electrically insulating substrate, wherein the at least one resistive heating element is provided on the electrically insulating substrate.

The electrically insulating substrate may comprise any suitable material. For example, the electrically insulating substrate may comprise one or more of: paper, glass, ceramic, anodized metal, coated metal, and Polyimide. The ceramic may comprise mica, Alumina (AI₂O₃) or Zirconia (ZrO₂). Preferably, the electrically insulating substrate has a thermal conductivity of less than or equal to about 40 Watts per metre Kelvin, preferably less than or equal to about 20 Watts per metre Kelvin and ideally less than or equal to about 2 Watts per metre Kelvin.

The heater may comprise a heating element comprising a rigid electrically insulating substrate with one or more electrically conductive tracks or wire disposed on its surface. The size and shape of the electrically insulating substrate may allow it to be inserted directly into an aerosol-generating substrate. If the electrically insulating substrate is not sufficiently rigid, the heating element may comprise a further reinforcement means. A current may be passed through the one or more electrically conductive tracks to heat the heating element and the aerosolgenerating substrate.

The heater may comprise an inductive heating arrangement. The inductive heating arrangement may comprise an inductor coil and a power supply configured to provide high frequency oscillating current to the inductor coil. As used herein, a high frequency oscillating current means an oscillating current having a frequency of between about 500 kHz and about 30 MHz. The heater may advantageously comprise a DC/AC inverter for converting a DC current supplied by a DC power supply to the alternating current. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field on receiving a high frequency oscillating current from the power supply. The inductor coil may be arranged to generate a high frequency oscillating electromagnetic field in the device cavity. The inductor coil may substantially circumscribe the device cavity. The inductor coil may extend at least partially along the length of the device cavity.

The heater may comprise an inductive heating element. The inductive heating element may be a susceptor element. As used herein, the term 'susceptor element' refers to an element comprising a material that is capable of converting electromagnetic energy into heat. When a susceptor element is located in an alternating electromagnetic field, the susceptor is heated. Heating of the susceptor element may be the result of at least one of hysteresis losses and eddy currents induced in the susceptor, depending on the electrical and magnetic properties of the susceptor material.

A susceptor element may be arranged such that, when the aerosol-generating article is received in the cavity of the aerosol-generating device, the oscillating electromagnetic field generated by the inductor coil induces a current in the susceptor element, causing the susceptor element to heat up. The aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a magnetic field strength (H-field strength) of between 1 and 5 kilo amperes per metre (kA m), preferably between 2 and 3 kA/m, for example about 2.5 kA/m. The electrically-operated aerosol-generating device is preferably capable of generating a fluctuating electromagnetic field having a frequency of between 1 and 30 MHz, for example between 1 and 10 MHz, for example between 5 and 7 MHz. The aerosol-generating article may comprise a susceptor element. The susceptor element is preferably located in contact with the aerosol-generating substrate.

A susceptor element may be located in the aerosol-generating device. The susceptor element may be located in the cavity. The aerosol-generating device may comprise only one susceptor element. The aerosol-generating device may comprise a plurality of susceptor elements. The susceptor element is preferably arranged to heat the outer surface of the aerosolgenerating substrate.

The susceptor element may comprise any suitable material. The susceptor element may be formed from any material that can be inductively heated to a temperature sufficient to release volatile compounds from the aerosol-generating substrate. Suitable materials for the elongate susceptor element include graphite, molybdenum, silicon carbide, stainless steels, niobium, aluminium, nickel, nickel containing compounds, titanium, and composites of metallic materials. Some susceptor elements comprise a metal or carbon. Advantageously the susceptor element may comprise or consist of a ferromagnetic material, for example, ferritic iron, a ferromagnetic alloy, such as ferromagnetic steel or stainless steel, ferromagnetic particles, and ferrite. A suitable susceptor element may be, or comprise, aluminium. The susceptor element preferably comprises more than about 5 percent, preferably more than about 20 percent, more preferably more than about 50 percent or more than about 90 percent of ferromagnetic or paramagnetic materials. Some elongate susceptor elements may be heated to a temperature in excess of about 250 degrees Celsius.

The susceptor element may comprise a non-metallic core with a metal layer disposed on the non-metallic core. For example, the susceptor element may comprise metallic tracks formed on an outer surface of a ceramic core or substrate.

The aerosol-generating device may comprise at least one resistive heating element and at least one inductive heating element. The aerosol-generating device may comprise a combination of resistive heating elements and inductive heating elements.

During use, the heater may be controlled to operate within a defined operating temperature range, below a maximum operating temperature. An operating temperature range between about 150 degrees Celsius and about 300 degrees Celsius in the heating chamber (or device cavity) is preferable. The operating temperature range of the heater may be between about 150 degrees Celsius and about 250 degrees Celsius.

Preferably, the operating temperature range of the heater may be between about 150 degrees Celsius and about 200 degrees Celsius. More preferably, the operating temperature range of the heater may be between about 180 degrees Celsius and about 200 degrees Celsius. In particular, it has been found that optimal and consistent aerosol delivery may be achieved when using an aerosol-generating device having an external heater, which has an operating temperature range between about 180 degrees Celsius and about 200 degrees Celsius, with aerosol-generating articles having a relatively low RTD (for example, with a downstream section RTD of less than 15 mm H₂O), as mentioned in the present disclosure.

In embodiments where the aerosol-generating article comprises a ventilation zone, the ventilation zone may be arranged to be exposed when the aerosol-generating article is received within the device cavity. Thus, the length of the device cavity or heating chamber may be less than the distance of the upstream end of the aerosol-generating article to a ventilation zone located along the downstream section. In other words, when the aerosol-generating article is received within the aerosol-generating device, the distance between the ventilation zone and the upstream end of the upstream element may be greater than the length of the heating chamber.

When the article is received within the device cavity, the ventilation zone may be located at least 0.5 mm away (in the downstream direction of the article) from the mouth end (or mouth end face) of the device cavity or device itself. When the article is received within the device cavity, the ventilation zone may be located at least 1 mm away (in the downstream direction of the article) from the mouth end (or mouth end face) of the device cavity or device itself. When the article is received within the device cavity, the ventilation zone may be located at least 2 mm away (in the downstream direction of the article) from the mouth end (or mouth end face) of the device cavity or device itself.

Preferably, a ratio between the distance between the ventilation zone and the upstream end of the upstream element and a length of the heating chamber is from about 1 .03 to about 1.13.

Such positioning of the ventilation zone ensures the ventilation zone is not occluded within the device cavity itself, while also minimising the risk of occlusion by a user’s lips or hands as the ventilation zone is located at the most upstream position from the downstream end of the article as reasonably possible without being occluded within the device cavity.

The aerosol-generating device may comprise a power supply. The power supply may be a DC power supply. The power supply may be a battery. The power supply may be a nickel- metal hydride battery, a nickel cadmium battery, or a lithium based battery, for example a lithiumcobalt, a lithium-iron-phosphate or a lithium-polymer battery. However, in some embodiments the power supply may be another form of charge storage device, such as a capacitor. The power supply may require recharging and may have a capacity that allows for the storage of enough energy for one or more user operations, for example one or more aerosol-generating experiences. For example, the power supply may have sufficient capacity to allow for continuous heating of an aerosol-generating substrate for a period of around six minutes, corresponding to the typical time taken to smoke a conventional cigarette, or for a period that is a multiple of six minutes. In another example, the power supply may have sufficient capacity to allow for a predetermined number of puffs or discrete activations of the heater. Below, there is provided a non-exhaustive list of non-limiting examples. Any one or more of the features of these examples may be combined with any one or more features of another example, embodiment, or aspect described herein.

EX1. An aerosol-generating article comprising a rod of aerosol-generating substrate; and a downstream section provided downstream of the rod of aerosol-generating substrate.

EX2. An aerosol-generating article according to example EX1 , wherein the downstream section comprises an air channelling element abutting the rod of aerosol-generating substrate, preferably abutting a downstream end of the rod of aerosol-generating substrate.

EX3. An aerosol-generating article according to example EX2, wherein the air channelling element of the downstream section is a downstream air channelling element.

EX4. An aerosol-generating article according to any preceding example, further comprising an upstream section located upstream of the rod of aerosol-generating substrate, the upstream section comprising at least one upstream element.

EX5. An aerosol-generating article according to example EX4, wherein the at least one upstream element comprising an upstream air channelling element.

EX6. An aerosol-generating article according to example EX4 or EX5, wherein an upstream end of the upstream element defines an upstream end of the aerosol-generating article.

EX7. An aerosol-generating article according to example EX1 , further comprising an upstream section located upstream of the rod of aerosol-generating substrate and a downstream section located downstream of the rod of aerosol-generating substrate, the upstream section comprising an upstream air channelling element abutting an upstream end of the rod of aerosol-generating substrate and the downstream section comprising a downstream air channelling element abutting a downstream end of the rod of aerosol-generating substrate.

EX8. An aerosol-generating article according to any preceding example, wherein the air channelling element comprises at least one outer air passageway, wherein at least one outer air passageway may define an internal air passageway or an external air passageway.

EX9. An aerosol-generating article according to any preceding example, wherein the air channelling element comprises a groove defined on an external surface of the body of the air channelling element, the groove defining an external air passageway extending from an upstream end of the air channelling element to a downstream end of the air channelling element. EX10. An aerosol-generating article according to any preceding example, wherein the body of the air channelling element comprises a core portion and a peripheral portion where the at least one groove is defined, wherein the core portion is substantially solid.

EX1 1 . An aerosol-generating article according to any preceding example, wherein the air channelling element does not define an internal cavity.

EX12. An aerosol-generating article according to any preceding example, wherein the air channelling element comprises a body comprising a core portion and a peripheral portion, the core portion comprising one or more inner air passageways and the peripheral portion comprising one or more outer air passageways, wherein a total cross-sectional area of the one or more outer air passageways is greater than a total cross-sectional area of the one or more inner air passageways.

EX13. An aerosol-generating article according to any preceding example, wherein a ratio of the total cross-sectional area of the one or more outer air passageways to the total cross-sectional area of the one or more inner air passageways is at least 2.

EX14. An aerosol-generating article according to any preceding example, wherein a ratio of the total cross-sectional area of the one or more outer air passageways to the total cross-sectional area of the one or more inner air passageways is at least 3.

EX15. An aerosol-generating article according to any preceding example, wherein a ratio of the total cross-sectional area of the one or more outer air passageways to the total cross-sectional area of the one or more inner air passageways is no more than 10.

EX16. An aerosol-generating article according to any preceding example, wherein the one or more outer air passageways comprises at least four outer air passageways.

EX17. An aerosol-generating article according to any preceding example, wherein each outer air passageway is defined by a groove provided on an external surface of the or each air channelling element.

EX18. An aerosol-generating article according to any preceding example, wherein each outer air passageway is defined by an internal cavity or air channel extending along the or each air channelling element.

EX19. An aerosol-generating article according to any preceding example, wherein a ratio of the total cross-sectional area of the one or more outer air passageways to the total cross-sectional area of the air channelling element is at least about 30 percent. EX20. An aerosol-generating article according to any preceding example, further comprising a mouthpiece element provided downstream of the rod of aerosol-generating substrate, wherein the air channelling element is located upstream of the rod of aerosol-generating substrate or between the rod of aerosol-generating substrate and the mouthpiece element.

EX21. An aerosol-generating article according to any preceding example, further comprising a mouthpiece element provided downstream of the rod of aerosol-generating substrate, wherein the upstream air channelling element is located upstream of the rod of aerosol-generating substrate or the downstream air channelling element is located between the rod of aerosolgenerating substrate and the mouthpiece element.

EX22. An aerosol-generating article according to any preceding example, further comprising a hollow tubular element provided downstream of the rod of aerosol-generating substrate, wherein the air channelling element is located upstream of the rod of aerosol-generating substrate or between the rod of aerosol-generating substrate and the hollow tubular element.

EX23. An aerosol-generating article according to any preceding example, further comprising a hollow tubular element provided downstream of the rod of aerosol-generating substrate, wherein the upstream air channelling element is located upstream of the rod of aerosol-generating substrate or the downstream air channelling element is located between the rod of aerosolgenerating substrate and the hollow tubular element.

EX24. An aerosol-generating article according to any preceding example, wherein the or each air channelling element is substantially air impermeable.

EX25. An aerosol-generating article according to any preceding example, wherein the or each air channelling element is formed by thermoforming.

EX26. An aerosol-generating article according to any preceding example, wherein a depth of a groove is at least 0.5 mm.

EX27. An aerosol-generating article according to any preceding example, wherein a depth of a groove is no greater than 2 mm.

EX28. An aerosol-generating article according to any preceding example, wherein the or each air channelling element comprises at least four grooves.

EX29. An aerosol-generating article according to any preceding example, wherein a groove traces a helical path or a waveform path.

EX30. An aerosol-generating article according to any preceding example, further comprising a wrapper circumscribing the or each air channelling element, wherein the wrapper overlies the external air passageway defined by a groove such that the wrapper defines a boundary of the external air passageway.

EX31. An aerosol-generating article according to any preceding example, further comprising a ventilation zone.

EX32. An aerosol-generating article according to example EX31 , wherein the ventilation zone is provided at a location along the hollow tubular element of the downstream section.

EX33. An aerosol-generating article according to any preceding example, wherein the rod of aerosol-generating substrate has a length of between 8 millimetres and 16 millimetres.

EX34. An aerosol-generating article according to any preceding example, wherein the rod of aerosol-generating substrate has a resistance to draw (RTD) of between 4 mm H₂O and 10 mm H₂O.

EX35. An aerosol-generating article according to any preceding example, wherein the aerosolgenerating substrate comprises a shredded tobacco material.

EX36. An aerosol-generating article according to example EX35, wherein the shredded tobacco material has an average density of between 150 milligrams per cubic centimetre and 500 milligrams per cubic centimetre.

EX37. An aerosol-generating article according to any preceding example, wherein the aerosolgenerating substrate comprises one or more aerosol formers and wherein the content of aerosol former in the aerosol-generating substrate is between 10 percent and 20 percent by weight, on a dry weight basis.

EX38. An aerosol-generating article according to example EX37, wherein the aerosol former comprises one or more of glycerine and propylene glycol.

EX39. An aerosol-generating article according to any preceding example, wherein the aerosolgenerating substrate comprises tobacco cut filler.

EX40. An aerosol-generating article according to any preceding example, wherein the external diameter of the article is substantially uniform along its length.

EX41. An aerosol-generating system comprising an aerosol-generating article according to any one of the preceding examples and an aerosol-generating device comprising a heating chamber for receiving the aerosol-generating article and at least a heating element provided at or about the periphery of the heating chamber. In the following, the invention will be further described with reference to the drawings of the accompanying Figures, wherein:

Figure 1 a shows a schematic side perspective, exploded view of an aerosol-generating article in accordance with an embodiment of the invention;

Figure 1 b shows a schematic side perspective view of an assembled aerosol-generating article as shown in Figure 1 a;

Figure 2 shows a schematic side perspective view Of an aerosol-generating article in accordance with an embodiment of the invention;

Figure 3 shows a schematic side perspective view of an aerosol-generating article in accordance with an embodiment of the invention;

Figure 4 shows a schematic side perspective view of an aerosol-generating article in accordance with an embodiment of the invention;

Figure 5a shows a cross-sectional view of an air channelling element of an aerosol- generating article in accordance with an embodiment of the invention;

Figure 5b shows a cross-sectional view of an air channelling element of an aerosol- generating article in accordance with an embodiment of the invention;

Figure 6a shows a schematic side perspective, exploded view of an aerosol-generating article in accordance with an embodiment of the invention;

Figure 6b shows a schematic side perspective, exploded view of an aerosol-generating article in accordance with an embodiment of the invention;

Figure 6c shows a schematic side perspective, exploded view of an aerosol-generating article in accordance with an embodiment of the invention;

Figure 7 shows a cross-sectional view of an air channelling element of an aerosolgenerating article in accordance with an embodiment of the invention;

Figure 8a shows a side sectional view of an aerosol-generating system in accordance with the present disclosure;

Figure 8b shows a partial cross-sectional view of an air channelling element of an aerosolgenerating article along line A-A shown in Figure 8a; and

Figure 8c shows a cross-sectional view of an air channelling element of an aerosolgenerating article along line A-A shown in Figure 8a.

Figure 1 a illustrates an aerosol-generating article 10 comprising a rod of aerosol-generating substrate 12 and a downstream section at a location downstream of the rod 12 of aerosol- generating substrate. The aerosol-generating article 10 extends from an upstream or distal end 16 to a downstream or mouth end 18, which coincides with a downstream end of the downstream section. As shown in Figure 1 a, the downstream section comprises a downstream air channelling element 11 and a mouthpiece element 8. The aerosol-generating article 10 has an overall length of about 45 millimetres and an outer diameter of about 7.2 mm. A length of the aerosol-generating substrate 12 is about 8 mm.

The rod of aerosol-generating substrate 12 comprises a shredded tobacco material. The rod of aerosol-generating substrate 12 comprises 150 milligrams of a shredded tobacco material comprising from 13 percent by weight to 16 percent by weight of glycerine. The density of the aerosol-generating substrate is about 300 mg per cubic centimetre. The RTD of the rod of aerosol-generating substrate 12 is between about 6 to 8 mm H₂O. The rod of aerosol-generating substrate 12 is individually wrapped by a plug wrap (not shown).

The downstream air channelling element 11 is located immediately downstream of the rod of aerosol-generating substrate 12, the downstream air channelling element 11 being in longitudinal alignment with the rod 12. The upstream end of the downstream air channelling element 11 abuts the downstream end of the rod of aerosol-generating substrate 12.

Outer air passageways for air and aerosol to travel through are present in the form of grooves 5 provided around an external surface of the air channelling element 1 1. The air channelling element 1 1 comprises six grooves 5 extending longitudinally along the body of the air channelling element 1 1 .

The air channelling element 11 also comprises an inner air passageway 7 extending along and through the centre of the body of the air channelling element 11 .

A length of the downstream air channelling element 1 1 is about 12 mm.

The mouthpiece element 8 extends from the downstream end of the air channelling element 11 to the downstream or mouth end of the aerosol-generating article 10. The mouthpiece element 8 has a length of about 7 mm. An external diameter of the mouthpiece element 8 is about 7.2 mm. The mouthpiece element 8 comprises a low-density, cellulose acetate filter segment. The RTD of the mouthpiece element 8 is about 8 mm H₂O. The mouthpiece element 8 may be individually wrapped by a plug wrap (not shown).

Figure 1 b illustrates the aerosol-generating article 10 being assembled in a wrapper 52 circumscribing the components of the article 10. The outer air passageways are defined between the grooves 5 and an internal surface of the wrapper 52.

Figure 2 illustrates an aerosol-generating article 10a similar to aerosol-generating article 10, but having a ventilation zone 13 provided at a location along the air channelling element 11 . In more detail, the ventilation zone 13 is provided at about 16 millimetres from the downstream end 18 of the article 10. The ventilation zone 13 comprises a circumferential row of openings or perforations circumscribing the air channelling element 11 . The perforations of the ventilation zone 13 allow fluid ingress into the grooves 5 from the exterior of the article 10. Any other embodiments described herein may also have a ventilation zone that provides fluid communication between the exterior of the article 10 and any outer air passageways (including grooves) defined in the air channelling element. Figure 3 illustrates an aerosol-generating article 20 similar to the aerosol-generating article 10, but comprising a hollow tubular element 14, instead of the downstream air channelling element 1 1 , and an upstream section upstream of the rod of aerosol-generating substrate 12 comprising an upstream air channelling element 15. Similar, to the downstream air channelling element 1 1 , the upstream air channelling element 15 (or upstream or front plug) comprises outer air passageways for air to travel through in the form of grooves 5 provided around an external surface of the air channelling element 15. The air channelling element 15 also comprises six grooves 5 extending longitudinally along the body of the air channelling element 15. The hollow tubular element 14 is provided between the rod of aerosol-generating substrate 12 and the mouthpiece element 8. The upstream air channelling element 15 has a length of about 5 mm. The hollow tubular element 14 may have a length of about 10 mm.

Figure 4 illustrates an aerosol-generating article 30 similar to the aerosol-generating article

10, but further comprising an upstream section upstream of the rod of aerosol-generating substrate 12 comprising an upstream air channelling element 15, as described above.

Figures 5a & 5b show cross-sections of embodiments of an air channelling element 1 1 , 15. As shown in Figures 5a & 5b, the air channelling elements 11 , 15 comprise an inner air passageway 7 extending through a core portion C of the body of the air channelling element 11 , 15, in addition to the four grooves 5 defined on a peripheral portion P of the body of the air channelling element 1 1 , 15. The grooves 5 have a depth H of about 1 .5 mm. The body of the airchannelling element 1 1 , 15 has an external diameter D of about 7.2 mm. The inner air passageway 7 has a circular cross-section and has a diameter of about 1 mm.

Figures 6a, 6b & 6c respectively illustrate embodiments similar to those shown in Figures 1 a, 3 & 4. The aerosol-generating articles 61 , 62 and 63 respectively shown in Figures 6a, 6b & 6c differ in that the outer air passageways of the downstream or upstream air channelling elements 11 , 15 are not defined by grooves 5, but by internal, outer air passageways 51 extending along and through the body of the air channelling elements 1 1 , 15. The internal, outer air passageways 51 are defined around the inner air passageway 7. As shown in Figure 7, while the inner air passageway 7 is defined at a core portion C of the body of the air channelling element

1 1 , 15, the outer air passageways 51 are defined at a peripheral portion P of the body of the air channelling element 1 1 , 15. The air channelling elements 11 , 15 shown in Figures 6a, 6b & 6c comprise four outer air passageways 51 defined within the material of the air channelling elements 1 1 , 15, rather than on an external surface as the grooves 5 are. Accordingly, the total cross- sectional area of the outer air passageways 51 is greater than the total cross-sectional area of the inner air passageway 7. As an example, the diameters of the inner air passageway 7 and outer air passageways 51 are about 1 .5 mm.

Figure 8a portrays an aerosol-generating system 1 comprising an exemplary aerosolgenerating device 100 (only a portion thereof is shown for ease of reference) and an aerosol- generating article 10 according to the embodiments shown in Figures 1 a, 1 b and 6a. Any embodiment of the aerosol-generating article in accordance with the present disclosure may be used in the system 1 .

Figure 8a illustrates a downstream, mouth end portion of the aerosol-generating device 100 where a device cavity or heating chamber is defined and the aerosol-generating article 10 can be received. The aerosol-generating device 1 comprises a housing 24, extending between a mouth end and a distal end (not shown). The housing 24 comprises a peripheral wall 26. The peripheral wall 26 defines a device cavity for receiving an aerosol-generating article 10. The device cavity is defined by a closed, distal end and an open, mouth end. The mouth end of the device cavity is located at the mouth end of the aerosol-generating device 1. The aerosolgenerating article 10 is configured to be received through the mouth end of the device cavity (or heating chamber) and is configured to abut a distal, closed end of the device cavity.

A device air-flow intake 22 is defined at a distal end of the device cavity. Air may enter the aerosol-generating substrate 12 via the air-flow intake 22, ensuring fluid communication between the exterior of the device 1 and the rod of the aerosol-generating substrate 12.

The aerosol-generating device 1 further comprises an external heater 28 and a power source (not shown) for supplying power to the heater 28. A controller (not shown) is also provided to control such supply of power to the heater 28. The heater 28 is configured to controllably heat the aerosol-generating article 10 during use, when the aerosol-generating article 10 is received within the device 1. The heater 28 is in the form of a heater tube and is arranged to externally heat the aerosol-generating substrate 12.

Figures 8b & 8c display how aerosol is drawn from a peripheral portion PS of the rod of aerosol-generating substrate 12 during the initial heating stages. As shown in Figure 8b, upon heating of the aerosol-generating substrate 12, aerosol is primarily drawn from the peripheral portion PS of the substrate 12. The long dash-dot-dot line B denotes an imaginary border between a peripheral portion PS of the substrate 12 and a core portion CS of the substrate 12, which may take longer to heat up and to generate aerosol after the start of a heating cycle. The downstream air channelling element 1 1 advantageously encourages aerosol from the peripheral portion PS of the substrate 12 to be drawn through the outer air passageways defined by the grooves 5, thereby speeding up the generation and provision of consumable aerosol to a user further downstream. As shown in Figures 8b & 8c, aerosol from the core portion CS of the substrate 12 can be drawn through the inner air passageway 7.

For the purpose of the present description and of the appended claims, except where otherwise indicated, all numbers expressing amounts, quantities, percentages, and so forth, are to be understood as being modified in all instances by the term "about". Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein. In this context, therefore, a number A is understood as A ± 10% of A. Within this context, a number A may be considered to include numerical values that are within general standard error for the measurement of the property that the number A modifies. The number A, in some instances as used in the appended claims, may deviate by the percentages enumerated above provided that the amount by which A deviates does not materially affect the basic and novel characteristic(s) of the claimed invention. Also, all ranges include the maximum and minimum points disclosed and include any intermediate ranges therein, which may or may not be specifically enumerated herein.

Claims

-57- CLAIMS

1. An aerosol-generating article for producing an inhalable aerosol upon heating, the aerosol-generating article comprising: a rod of aerosol-generating substrate; a downstream section located downstream of the rod of aerosol-generating substrate, the downstream section comprising a downstream air channelling element abutting a downstream end of the rod of aerosol-generating substrate, wherein the downstream air channelling element comprises a body comprising a core portion and a peripheral portion, the core portion comprising one or more inner air passageways and the peripheral portion comprising one or more outer air passageways, wherein a total cross-sectional area of the one or more outer air passageways is greater than a total cross-sectional area of the one or more inner air passageways; and a ventilation zone located along the downstream air channelling element, wherein the ventilation zone establishes a fluid communication with the one or more outer air passageways.

2. An aerosol-generating article according to claim 1 , further comprising an upstream section located upstream of the rod of aerosol-generating substrate, the upstream section comprising an upstream air channelling element abutting an upstream end of the rod of aerosol-generating substrate, wherein the upstream air channelling element comprises a body comprising a core portion and a peripheral portion, the core portion comprising one or more inner air passageways and the peripheral portion comprising one or more outer air passageways, wherein a total cross- sectional area of the one or more outer air passageways is greater than a total cross-sectional area of the one or more inner air passageways.

3. An aerosol-generating article according to any preceding claim, wherein the downstream section further comprises a mouthpiece element, wherein the downstream air channelling element is located between the rod of aerosol-generating substrate and the mouthpiece element.

4. An aerosol-generating article according to any preceding claim, wherein the downstream section further comprises a hollow tubular element, wherein the downstream air channelling element is located between the rod of aerosol-generating substrate and the hollow tubular element.

5. An aerosol-generating article according to any preceding claim, wherein each outer air passageway is defined by a groove provided on an external surface of the air channelling element.

6. An aerosol-generating article according to any preceding claim, wherein a depth of a groove is at least 0.5 mm. -58-

7. An aerosol-generating article according to any preceding claim, wherein a depth of a groove is no greater than 2 mm.

8. An aerosol-generating article according to any one of claims 1 to 4, wherein each outer air passageway is defined by an internal cavity extending along the air channelling element.

9. An aerosol-generating article according to any preceding claim, wherein a ratio of the total cross-sectional area of the one or more outer air passageways to the total cross-sectional area of the one or more inner air passageways is at least 2.

10. An aerosol-generating article according to any preceding claim, wherein a ratio of the total cross-sectional area of the one or more outer air passageways to the total cross-sectional area of the one or more inner air passageways is no more than 10.

11. An aerosol-generating article according to any preceding claim, wherein the one or more outer air passageways comprises at least four outer air passageways.

12. An aerosol-generating article according to any preceding claim, wherein a ratio of the total cross-sectional area of the one or more outer air passageways to the total cross-sectional area of the air channelling element is at least about 30 percent.

13. An aerosol-generating article according to any preceding claim, wherein the aerosolgenerating substrate has an aerosol former content of at least 5 percent on a dry weight basis.

14. An aerosol-generating article according to any preceding claim, wherein the aerosolgenerating substrate has an aerosol former content of at least 10 percent on a dry weight basis.

15. An aerosol-generating system comprising an aerosol-generating article according to any one of the preceding claims and an aerosol-generating device comprising a heating chamber, wherein the aerosol-generating article is configured to be received within the heating chamber and wherein the aerosol-generating device comprises an external heater configured to externally heat the rod of aerosol-generating substrate.