EP3887741B1 - Heat exchanger and system for cooling a fluid comprising such a heat exchanger - Google Patents

Description

Technical field of the invention

The invention relates to a heat exchanger, in particular a tubular heat exchanger for an air or rail transport vehicle. The invention also relates to a system for cooling a fluid comprising such a heat exchanger. The invention also relates to an air conditioning system for a cabin of an air or rail transport vehicle equipped with such a cooling system.

Technology background

An environmental control system for an aircraft cabin, better known by the acronym ECS for the English name " Environmental Control System ", is intended to provide the cabin of the aircraft (which generally designates any interior space of the aircraft whose air pressure and/or temperature must be controlled, such as a passenger cabin, the pilot's cockpit, a hold, etc.) air at controlled pressure and/or temperature.

For this, it is known to take high pressure air from the propulsion engines of the aircraft and to treat this air by a plurality of equipment to bring it to a temperature and pressure compatible with the needs of the cabin.

Among this equipment, there is at least one air/air heat exchanger which aims to cool the air taken from the propulsion engines of the aircraft by the implementation of heat exchanges between this flow of hot air and a flow of 'cold air.

Thus, such a heat exchanger generally comprises a hot circuit and a transverse cold circuit configured to be able to ensure heat exchanges between the flow of air conveyed by the hot circuit (also referred to below as the hot pass) and the flow of air. cold air conveyed by the cold circuit (also referred to below as the cold pass).

The cold circuit can, for example, be supplied by a flow of air taken from the secondary flow of the engine, known under the name of fan air, whose temperature is close to the external environment of the aircraft, and which can therefore reach in flight temperatures of the order of -50°C and a pressure of the order of 200 mbar.

The cold circuit can also be supplied by a flow of air taken from a scoop of the aircraft which supplies an air channel, better known under the name RAM air.

The hot circuit can be fed directly by air taken from the propulsion engines or by air from the engines and already partially treated by equipment upstream of the air conditioning system.

In the case of electric air conditioning systems, the hot circuit can be supplied by air taken from outside the aircraft and compressed by suitable compressors.

Most of the heat exchangers used today on board aircraft consist of heat exchangers of the fin or plate type. These exchangers are formed of a heat exchange chamber of generally rectangular shape and comprise stacked layers of fins, for example corrugated, which form stacked circulation channels which extend alternately in directions perpendicular from one layer to the other. 'other. Thus, the hot pass which supplies one face of the exchanger circulates in the channels of the different layers and the cold pass which supplies a perpendicular face of the exchanger circulates in the transverse channels interposed between two channels of the hot pass. This architecture makes it possible to insert each hot channel between two cold channels over the entire length of the exchanger and therefore to ensure heat exchange between the two fluids.

The international request WO201802171 on behalf of the applicant describes such a heat exchanger.

US 4,440,217 discloses a countercurrent heat exchanger having two concentrically disposed conduits in a sealed housing.

US 2013/206374 discloses a heat exchanger comprising a central part provided with a maximum number of sub-channels.

WO 2016/057443 discloses a multi-branch branched flow heat exchanger for an aeronautical application.

These heat exchangers make it possible to cool the air taken from the engines or the ambient air compressed by dedicated compressors, before being treated by the other equipment of the air conditioning system in order to be able to supply the cabin of the aircraft. The cooling capacity of an exchanger is directly proportional to its size.

However, the size and the weight of a heat exchanger are two critical characteristics for aircraft manufacturers who constantly seek to limit the weight and the volume of the exchanger as much as possible while aiming for high cooling performance.

The inventors therefore sought a new solution making it possible to increase the exchange surfaces within the exchanger while minimizing the size of the exchanger.

The inventors have in particular sought to develop a heat exchanger which can be used, not only within the framework of the air conditioning systems of a transport vehicle, such as an aircraft, but also in all types of cooling systems requiring the cooling of a hot fluid from a source of hot fluid by a cold fluid from a source of cold fluid.

As such, the invention is not limited only to heat exchangers intended for air conditioning systems, but also to heat exchangers intended for all types of heat exchange applications.

Objectives of the invention

The invention aims to provide a heat exchanger which overcomes at least some drawbacks of the known solutions.

The invention aims in particular to provide, in at least one embodiment, a heat exchanger which makes it possible to optimize the exchange surfaces.

The invention also aims to provide, in at least one embodiment, an exchanger which has a reduced bulk compared to existing heat exchangers.

The invention also aims to provide, in at least one embodiment, an exchanger whose pressure drops are reduced.

The invention also aims to provide, in at least one embodiment, an exchanger which can be embedded in a fluid circulation pipe to functionalize such a pipe and thus reduce the size of the system.

The invention also aims to provide a system for cooling a hot fluid by a cold fluid equipped with a heat exchanger according to the invention.

The invention also aims to provide an air conditioning system equipped with a heat exchanger according to the invention.

The invention also aims to provide an air or rail transport vehicle equipped with an air conditioning system according to the invention.

Disclosure of Invention

• une chambre de circulation de fluide comprenant une entrée de fluide et une sortie de fluide destinée à être alimentée par un premier fluide, dit fluide extérieur, porté à une première température,
• une matrice d'échanges thermiques logée dans ladite chambre de circulation et formée d'une pluralité de tubulures d'échanges thermiques comprenant chacune au moins une paire de conduits imbriqués l'un dans l'autre, dits respectivement conduit intérieur et conduit extérieur, s'étendant le long d'une direction, dite direction longitudinale, et définissant :
  • o un canal de circulation d'un fluide, dit canal intérieur, délimité par ledit conduit intérieur, et adapté pour pouvoir être alimenté par un deuxième fluide, dit fluide intérieur, porté à une deuxième température, et
  • o un canal de circulation d'un fluide, dit canal intermédiaire, délimité par l'espace inter-conduits entre ledit conduit intérieur et ledit conduit extérieur, et adapté pour pouvoir être alimenté par un troisième fluide, dit fluide intermédiaire, porté à une troisième température, distincte de ladite première température.

To do this, the invention relates to a heat exchanger comprising:

• a fluid circulation chamber comprising a fluid inlet and a fluid outlet intended to be supplied with a first fluid, called external fluid, brought to a first temperature,
• a heat exchange matrix housed in said circulation chamber and formed of a plurality of heat exchange pipes each comprising at least one pair of ducts nested one inside the other, respectively called the inner duct and the outer duct, s extending along a direction, called the longitudinal direction, and defining:
  • o a fluid circulation channel, called inner channel, delimited by said inner duct, and adapted to be able to be supplied with a second fluid, called inner fluid, brought to a second temperature, and
  • o a fluid circulation channel, called intermediate channel, delimited by the inter-duct space between said inner conduit and said outer conduit, and adapted to be able to be supplied by a third fluid, called intermediate fluid, carried to a third temperature, distinct from said first temperature.

The heat exchanger according to the invention is characterized in that at least one heat exchange pipe - in particular each heat exchange pipe - comprises at least two pairs of nested ducts, said pairs being interconnected by at least a transverse strut.

A heat exchanger according to the invention has a configuration particular with a heat exchange matrix formed of a plurality of heat exchange pipes housed in a fluid circulation chamber, of which at least one heat exchange pipe comprises at least two pairs of ducts nested one inside the 'other. Such a heat exchange matrix configuration has the advantage of having a double heat exchange surface and thus of increasing the heat exchange surfaces while reducing the size of said heat exchanger.

More particularly, a heat exchanger according to the invention comprises a chamber in which circulates a fluid brought to a first temperature. A plurality of heat exchange pipes each comprising at least one pair of ducts nested one inside the other is arranged in this chamber. Each pipe comprises at least one pair of conduits defined by an inner conduit housed in an outer conduit respectively delimiting an inner channel and an intermediate inter-duct channel. Also, each channel (respectively the inner channel and the intermediate channel) can be supplied with a dedicated fluid.

According to the invention, said outer and inner conduits are nested one inside the other in order to allow the intermediate fluid to circulate in the intermediate channel delimited by the inter-duct space and the inner fluid to circulate in the inner channel delimited through the inner pipe. The inner conduit forms the heat exchange surface between the inner fluid and the intermediate fluid while the outer conduit forms the heat exchange surface between the outer fluid supplying the chamber and the intermediate fluid. The nested ducts therefore form a double heat exchange surface for the intermediate fluid.

Thus, the intermediate fluid circulating in the intermediate conduit can be heated or cooled (depending on the temperatures of the interior, intermediate and exterior fluids) both by the interior fluid circulating in the interior channel and by the exterior fluid circulating in the circulation chamber of fluid. This double heat exchange permitted by the particular structure of the exchanger according to the invention therefore makes it possible to cool and/or heat the intermediate fluid with better efficiency than the systems of the prior art.

According to the invention, the configuration of the nested ducts not only makes it possible to form a double heat exchange zone, but also to reduce the size of the exchanger. In particular, the double heat exchange has the advantage of reducing the number of heat exchange pipes within an exchanger while benefiting from an exchange surface equivalent to that of an existing exchanger. The exchanger according to the invention makes it possible to increase the exchange surface with respect to an existing exchanger and therefore to obtain a more efficient heat exchanger, with equivalent bulk, or to obtain, with equivalent performance, a reduced bulk.

According to the invention, said inner and outer fluids intended to respectively supply said inner channel of a pair of nested ducts and said fluid circulation chamber come from the same source of fluid.

Thus said exterior and interior fluids are of the same nature and can be brought to the same temperature. The inner and outer fluids thus surround the intermediate fluid circulating in the intermediate channel. The intermediate fluid therefore undergoes heat exchanges of the same nature, both at the level of the internal wall delimited by the inner conduit and at the level of the outer wall delimited by the outer conduit.

Furthermore, according to the invention, the external and internal fluid is the fluid of the cold pass and the intermediate fluid is the fluid of the hot pass. The cold pass thus makes it possible to cool the hot pass by circulating around it in the chamber and also in the center of the hot pass by circulating in the inner duct delimiting the inner channel.

The intermediate fluid is thus cooled more efficiently given that said nested ducts delimiting the inter-duct space in which the intermediate fluid can circulate are both in contact with a fluid brought to a lower temperature. In this case, the cooling of the intermediate fluid is facilitated and the cooling efficiency of said fluid is improved.

According to the invention, the inner channel can communicate with said fluid circulation chamber so that the fluid circulating in said chamber is the same fluid circulating in said inner channel.

Said inner duct of the heat exchange pipe then opens directly into said fluid circulation chamber. Also, the same supply system is sufficient to supply both the inner channel and said circulation chamber. Thus, this configuration only requires a single fluid passing through the fluid circulation chamber from the inlet to the outlet, supplying at the same time said inner channels of the heat exchange pipes.

According to the invention, the transverse spacer, also referred to in the text as "connecting spacer", arranged between the pairs of nested ducts can create turbulence within the fluid circulation chamber which improves heat exchange between the fluid external circulating in the chamber and the intermediate fluid which circulates in the intermediate channels.

The connecting spacer can also have a heat exchange functionality by conducting at least part of the heat captured from the external duct to the mixing chamber.

In addition, a pipe according to the invention equipped with a spacer is rigid so that a plurality of pipes according to the invention makes it possible, when the pipes are associated with each other, to form a compact matrix network of pipes of trades.

According to a variant of the invention, the interior, intermediate and exterior fluid flows are air flows, originating respectively from a flow of hot air, for example taken from a propulsion engine of an aircraft and a flow of cold air, taken for example from outside the aircraft.

Advantageously and according to the invention, at least one heat exchange pipe—in particular each heat exchange pipe—comprises at least two pairs of nested ducts, the said intermediate channels of which are supplied by the same intermediate fluid distributor.

According to this advantageous variant, a distributor makes it possible to supply the various pairs of nested ducts of the heat exchange tubing.

Such an intermediate fluid distributor is for example formed of a tube comprising an intermediate fluid inlet which splits into several tubes to form several intermediate fluid supply sources of the channels intermediaries. In the case where the tubing comprises two pairs of nested ducts, the distributor has a fluid inlet and two fluid outlets opening into each of the two intermediate channels of said two pairs of nested ducts.

Preferably, said distributor has the general shape of a Y, the base of the Y forming the inlet of the intermediate fluid in the tubing and the two branches of the Y forming supply channels for the intermediate channels.

Each distributor can be connected to the same supply system to facilitate the distribution of intermediate fluid in all the distributors and subsequently in the intermediate channels of the various heat exchange pipes.

In the case where the tubing comprises three pairs of nested ducts, the distributor has a fluid inlet and three fluid outlets opening into each of the three intermediate channels of the three pairs of nested ducts. Of course, nothing prevents the provision of pipes comprising more than three pairs of nested ducts for an equivalent effect.

A distributor according to this variant of the invention therefore makes it possible to supply a plurality of intermediate channels of a plurality of pairs of ducts by a single supply of intermediate fluid.

Advantageously and according to the invention, at least one inner duct - in particular each inner duct - of at least one pair of nested ducts - in particular of each pair of nested ducts - passes through said intermediate fluid distributor.

This makes it possible to supply the interior channels, either directly by the fluid circulating in the circulation chamber, or by a fluid dedicated to the interior channels, in which case the interior ducts also pass through the exterior fluid circulation chamber.

According to this variant, an intermediate fluid supply system can distribute said intermediate fluid into said intermediate channels via distributors. The interior fluid supply can be done thanks to a second supply system dedicated to the distribution of said interior fluid capable of supplying said interior channels which may extend outside the circulation chamber.

Advantageously and according to the invention, at least one inner duct - in particular each inner duct - of at least one pair of nested ducts - in particular of each pair of nested ducts - passes through said intermediate fluid distributor and opens into said circulation chamber.

According to this variant, the interior ducts open directly into the fluid circulation chamber so that the supply of the fluid circulation chamber also allows the supply of the interior channels delimited by the interior ducts.

Advantageously and according to the invention, at least one transverse spacer - in particular each transverse spacer - comprises at least one opening configured to allow the passage of said external fluid between said pairs of nested ducts connected by this spacer in a direction having an angle between 0 ° and 90° with respect to said longitudinal direction.

According to this variant, said transverse spacer comprises at least one opening to allow better circulation of said external fluid within the circulation chamber between the pairs of ducts.

According to this variant, the external fluid is evenly distributed in said circulation chamber in order to promote heat exchange between said external fluid and said intermediate fluid flowing in the intermediate channel of the pipes.

Advantageously and according to the invention, at least one heat exchange pipe - in particular each heat exchange pipe - comprises at least one pair of nested ducts, the ducts of which are connected to each other by a junction rod which extends in the intermediate channel between the inner duct and the outer duct.

According to this variant, the inner and outer ducts which together form a pair of nested ducts of the tubing are mechanically connected by at least one junction strip which extends in the inter-duct space between the ducts to stiffen the assembly as well form.

Advantageously and according to the invention, at least one heat exchange pipe - in particular each heat exchange pipe - comprises at least one pair of nested cylindrical pipes.

According to this variant, the ducts are cylindrical. A cylindrical conduit is understood in the mathematical sense of the term, that is to say that such a conduit is a solid generated by a straight line which moves parallel to itself on a generatrix. Such a generator can be square, circular, oval, etc.

Preferably, the nested ducts are cylindrical with a circular base.

According to this variant, said cylindrical ducts are optimized to be arranged in a fluid circulation chamber which is preferably also cylindrical with a circular base. In other words, the heat exchanger then forms a cylindrical tubular exchanger which can be embedded in a cylindrical pipe. Thus, the tubular heat exchanger comprising a cylindrical chamber can be easily integrated within a cylindrical fluid circulation pipe.

An exchanger according to this variant of the invention, embedded in a cylindrical pipe, makes it possible to functionalize this pipe, and therefore to limit the size of the exchanger by housing it within equipment already present, thus freeing up space. outside the pipe.

According to this variant, the cylindrical shape of the ducts also makes it possible to reduce the pressure forces which are exerted on the walls of the nested ducts by the fluids circulating inside and outside the ducts.

The heat exchange pipes of a heat exchanger according to the invention can also have any shape. Thus, the pipes can for example be cylindrical by extending straight along a longitudinal direction, but nothing prevents providing other embodiments in which the pipes are curved, or draw spirals, or any other form whatsoever.

Advantageously and according to the invention, at least one heat exchange pipe - in particular each heat exchange pipe - comprises at least one pair of concentric nested pipes.

This advantageous variant makes it possible in particular to standardize the forces exerted on the ducts and to simplify the operations of nesting the ducts one inside the other.

Advantageously and according to the invention, said heat exchanger further comprises a casing, said casing delimiting the fluid circulation chamber.

According to this variant, the chamber of the exchanger is delimited by a casing which comprises at least a plurality of pipes arranged in said chamber so that the exchanger is integrated into a pipeline, preferably cylindrical.

The invention also relates to a system for cooling a fluid having a first temperature, called hot fluid, by a fluid having a second temperature, called cold fluid, comprising a hot fluid circuit adapted to be able to be supplied with hot fluid by a source of hot fluid, and a cold fluid circuit adapted to be able to be supplied with cold fluid by a source of cold fluid.

A cooling system according to the invention is characterized in that it further comprises a heat exchanger according to the invention, said hot circuit supplying said intermediate channels and said cold circuit supplying said interior channels and said circulation chamber of said exchanger.

A cooling system according to the invention can be implemented in all applications requiring cooling of a hot fluid by a cold fluid (cooling of electronics by a heat transfer fluid; cooling of air taken from a propulsion engine for a system air conditioning, etc.). The fluids can be of the same nature (air/air or liquid/liquid) or of different nature (air/liquid or liquid/air).

The advantages of a heat exchanger according to the invention apply mutatis mutandis to a cooling system according to the invention.

Advantageously and according to the invention, said intermediate channels and said inner channels are fed in countercurrent by said hot and cold circuits respectively.

According to this variant, the interior fluid circulates in the interior channel of each tube against the current of the intermediate fluid which circulates in the intermediate channel of each tube, that is to say that the fluids each circulate in opposite directions. As a variant or in combination, the external fluid can also circulate against the current of said intermediate fluid.

The invention also relates to an air conditioning system for a cabin of a transport vehicle comprising at least one air cooling system according to the invention.

According to this variant, the hot air circuit is for example supplied by air taken from a propulsion engine of the aircraft and said cold air circuit is for example taken from the secondary flow of the engine of the aircraft or from the exterior of the aircraft.

Of course, nothing prevents the use of an exchanger according to the invention by providing that the hot fluid does not come from a sample taken from the propulsion engines of the aircraft, which may for example be the case in the context of electric air conditioning systems for which the hot air is obtained by means of compressing the air taken from outside the aircraft.

The invention also relates to an air, rail or automobile transport vehicle comprising at least one propulsion engine, a cabin and at least one air conditioning system for said cabin, characterized in that the air conditioning system for the cabin is an air conditioning system according to the invention.

The advantages of an air conditioning system according to the invention apply mutatis mutandis to a transport vehicle according to the invention.

The invention also relates to a heat exchanger, a fluid cooling system, an air conditioning system and an aircraft, characterized in combination by all or some of the characteristics mentioned above or below.

List of Figures

• [Fig. 1] est une vue schématique en coupe d'un échangeur selon un mode de réalisation de l'invention.
• [Fig. 2] est une vue schématique en perspective d'une pluralité de tubulures d'échanges thermiques formant la matrice d'échanges thermiques d'un échangeur selon un mode de réalisation de l'invention.
• [Fig. 3a] est une vue schématique en perspective avant d'une tubulure d'un échangeur selon un mode de réalisation de l'invention.
• [Fig. 3b] est une vue schématique en perspective arrière d'une tubulure d'un échangeur selon un mode de réalisation de l'invention.
• [Fig. 4a] est une vue schématique en perspective avant d'une tubulure d'un échangeur selon un autre mode de réalisation de l'invention.
• [Fig. 4b] est une vue schématique en perspective arrière d'une tubulure d'un échangeur selon un autre mode de réalisation de l'invention.
• [Fig. 5] est une vue schématique d'une matrice d'échanges thermiques d'un échangeur selon un mode de réalisation de l'invention.
• [Fig. 6] est une vue schématique d'une matrice d'échanges thermiques d'un échangeur selon un mode de réalisation de l'invention.
• [Fig. 7] est une vue schématique d'un aéronef selon un mode de réalisation de l'invention.

Other aims, characteristics and advantages of the invention will appear on reading the following description given solely by way of non-limiting and which refers to the appended figures in which:

• [ Fig. 1 ] is a schematic sectional view of an exchanger according to one embodiment of the invention.
• [ Fig. 2 ] is a schematic perspective view of a plurality of heat exchange pipes forming the heat exchange matrix of an exchanger according to one embodiment of the invention.
• [ Fig. 3a ] is a schematic front perspective view of a tube of an exchanger according to one embodiment of the invention.
• [ Fig. 3b ] is a schematic view in rear perspective of a tube of an exchanger according to one embodiment of the invention.
• [ Fig. 4a ] is a schematic front perspective view of a tube of an exchanger according to another embodiment of the invention.
• [ Fig. 4b ] is a schematic view in rear perspective of a tube of an exchanger according to another embodiment of the invention.
• [ Fig. 5 ] is a schematic view of a heat exchange matrix of an exchanger according to one embodiment of the invention.
• [ Fig. 6 ] is a schematic view of a heat exchange matrix of an exchanger according to one embodiment of the invention.
• [ Fig. 7 ] is a schematic view of an aircraft according to one embodiment of the invention.

Detailed description of an embodiment of the invention

In the figures, scales and proportions are not strictly adhered to, for purposes of illustration and clarity. Throughout the following detailed description with reference to the figures, unless otherwise indicated, each element of the tubular heat exchanger is described as it is arranged when the exchanger is housed in an air circulation duct which is extends along a direction, called the longitudinal direction, which coincides with the direction along which the heat exchanger pipes extend. This configuration is represented in particular on the figure 1 .

In addition, identical, similar or analogous elements are designated by the same references in all the figures.

In the following, the description considers that the heat exchanger is installed within an air conditioning system, it being understood that the exchanger can be used for other applications than the cooling of high temperature air, taken for example from a propulsion engine of an aircraft.

The figure 1 schematically illustrates a tubular heat exchanger 10 embedded in a conduit 23 for air circulation. The exchanger may comprise a casing embedded in the pipe 23.

The exchanger 10 further comprises a heat exchange matrix 30, housed in a fluid circulation chamber 20, and formed of a plurality of heat exchange pipes 31 extending in a longitudinal direction 70, which coincides by example with the direction along which the pipe 23 runs.

Chamber 20 is supplied with air brought to a first temperature. This air is for example air taken from outside the aircraft. This fresh air is schematically represented by the arrow referenced 72a on the figure 1 .

The heat exchange pipes 31 have, in the embodiment of the figure 2 , 3a , 3b , 5 and 6 , a Y-shape, the base of the Y forming a distributor 50 for supplying intermediate channels, forming the branches of the Y, in an intermediate air brought to a second temperature, distinct from the temperature of the air supplying the chamber 20. This intermediate air is for example hot air taken from the propulsion engines of the aircraft. This hot air is schematically represented by the arrow referenced 71 on the figure 1 .

The pipes 31 are also configured to have interior channels supplied with fresh air, which may be the same air as that which supplies the chamber 20. This air is schematically represented by the arrow 72b on the figure 1 . According to another embodiment, the interior channels can be supplied with air brought to another temperature distinct from the temperatures of the exterior air and of the intermediate air.

The picture 2 illustrates in more detail a portion of the heat exchange matrix of an exchanger according to the invention. Each tube comprises two pairs 32; 33 of conjugate concentric conduits connected to a distributor 50 of intermediate fluid. Distributor 50 includes an inlet 51 intermediate fluid supplied by a supply system not shown in detail in the figures and two fluid outlets 52 for supplying the intermediate channels 32d and 33d of the pairs 32; 33 of ducts nested one inside the other. The two pairs 32, 33 of ducts are interconnected by means of a transverse spacer 40 which further comprises an opening 41 allowing the passage of the air circulating in the chamber 20.

The figures 3a and 3b illustrate a Y-shaped tubing 31. The Y-shaped tubing 31 can be fabricated by an additive printing system, such as a 3D printer.

As illustrated in these figures, the Y-shaped tubing 31 comprises two pairs 32; 33 of ducts nested one inside the other, which are also concentric in the embodiment of the figures. Each pair of ducts is formed by two nested ducts, respectively an inner duct 32a; 33a and an outer conduit 32b; 33b.

The inner ducts 32a; 33a delimit an inner channel 32c; 33c circulation of interior air, which is for example cold air.

The inter-duct space formed by the inner duct 32a; 33a and the outer pipe 32b; 33b delimits an intermediate channel 32d; 33d circulation of an intermediate air, which is for example hot air.

The outer conduit 32b; 33b is connected to the two fluid outlets 52 of the distributor 50 so that the intermediate fluid supplying the distributor through the inlet 51 is distributed to the intermediate channels 32d; 33d.

The inner channel 32c; 33c of each pair of ducts opens into the fluid circulation chamber 20 so that the air flow circulating in the inner channel is the air flow circulating in the chamber 20. To do this, the outlets 52 of the distributor 50 connected to the external conduits 32b; 33b are traversed by the internal conduit 32a; 33a which opens directly into the fluid circulation chamber 20 so that the chamber 20 and the interior channels are fed by the same flow of fresh air.

The matrix 30 is formed of pipes 31 in the form of Y whose pairs of ducts 32; 33 conjugate concentrics are parallel to each other. The pipes 31 in the shape of a Y are associated with each other to form a layer of pipes 31. Several layers can be stacked on top of each other so as to constitute a matrix network of pipes 31 within a chamber 20 to form the matrix 30. The layers of Y-shaped pipes 31 can be stacked so that the inlets 51 of the set of distributors 50 are staggered with respect to each other; thus creating spaces for the passage of the external fluid circulating in the chamber 20.

The figures 4a and 4b illustrate a tubing according to another embodiment of the invention. In this embodiment, the tubing comprises a distributor 50 and three pairs of nested conduits 32, 33, 34 one inside the other. In addition, the distributor 50 feeds the three pairs 32, 33, 34 of conduits in parallel from a single feed from the distributor.

According to other embodiments not shown, a manifold may comprise four or more pairs of nested conduits.

On the figure 5 , there are on either side of the inlet 51 of the distributor 50, the internal channels 32c and 33c in which the internal fluid circulates which also supplies the chamber 20 in which the matrix 30 of thermal exchanges is housed, and not shown in this figure.

The figure 6 schematically illustrates the pairs of conduits 32; 33 nested and in particular the outer conduit 32b and 33b which are interconnected by the spacer 40 transverse.

The heat exchanger 10 can according to this embodiment be integrated into an air conditioning system 62 . In addition, the pipes 31 as illustrated are cylindrical and thus make it possible to obtain a cylindrical matrix 30 which can be housed in a chamber 20 delimited by a cylindrical casing, which can be integrated into a cylindrical air circulation pipe and in particular in an air conditioning system 62 fitted to an aircraft 60.

As illustrated by the figure 7 , the air conditioning system 62 comprises a hot circuit and a cold circuit intended to supply the tubular exchanger according to the invention. The intermediate fluid is the fluid conveyed by the hot circuit and is for example an air taken from the propulsion engines 61 of the aircraft. The cold circuit which makes it possible to supply the interior fluid and the exterior fluid is for example an air circuit taken from the secondary flow of the engine or an air taken from outside the aircraft.

The tubular heat exchanger 10 can be directly embedded in an air circulation pipe and in particular in an air conditioning system 62 which equips an aircraft 60. According to this embodiment, the size of the exchanger 10 is thus limited while having an increased heat exchange surface with a system of nested ducts allowing a double heat exchange.

The present invention has been described in connection with an aeronautical application, in particular for an air conditioning system for an aircraft cabin.

This being the case, a heat exchanger according to the invention can be implemented, not only within the framework of the air conditioning systems of a transport vehicle, such as an aircraft, but also in all types of air conditioning systems. cooling requiring the cooling of a hot fluid from a source of hot fluid by a cold fluid from a source of cold fluid.

As such, a heat exchanger according to the invention can equip, not only systems as described in the application EP3342709 on behalf of the applicant, but also systems as described in the applications EP3190282 , WO201634830 , EP3392146 , WO2018122334 , FR2894563 Where FR3051894 . This list is of course not exhaustive and is cited only to enable those skilled in the art to perceive the application potential of a heat exchanger according to the invention.

Claims (13)

1. Heat exchanger (10) comprising:

   - a fluid circulation chamber (20) comprising a fluid inlet (21) and a fluid outlet (22) intended to be supplied with a first fluid, referred to as outer fluid, brought to a first temperature,

   - a heat exchange matrix (30) housed in said circulation chamber (20) and formed by a plurality of heat exchange tubes (31) each comprising at least one pair of ducts (32; 33) nested one inside the other, referred to as inner duct (32a; 33a) and outer duct (32b; 33b), respectively, extending along a direction, referred to as longitudinal direction (70), and defining:

   o a channel for the circulation of a fluid, referred to as inner channel (32c; 33c), delimited by said inner duct (32a; 33b), and suitable for being able to be supplied with a second fluid, referred to as inner fluid, brought to a second temperature, and

   o a channel for the circulation of a fluid, referred to as intermediate channel (32d; 33d), delimited by the inter-duct space between said inner duct (32a; 33a) and said outer duct (32b; 33b), and suitable for being able to be supplied with a third fluid, referred to as intermediate fluid, brought to a third temperature, different from said first temperature,

   characterized in that at least one heat exchange tube (31) comprises at least two pairs of nested ducts (32; 33), said pairs being connected to each other by at least one transverse spacer (40).
2. Heat exchanger according to claim 1, characterized in that at least one heat exchange tube (31) comprises at least two pairs of nested ducts (32; 33), said intermediate channels (32d; 33d) of which are supplied by the same intermediate fluid distributor (50).
3. Heat exchanger according to claim 2, characterized in that at least one inner duct (32a; 33a) of at least one pair of nested ducts (32; 33) passes through said intermediate fluid distributor (50).
4. Heat exchanger according to claim 3, characterized in that at least one inner duct (32a; 33a) of at least one pair of nested ducts (32; 33) passes through said intermediate fluid distributor (50) and opens into said circulation chamber (20).
5. Heat exchanger according to any of claims 1 to 4, characterized in that at least one transverse spacer (40) comprises at least one opening (41) configured to allow the passage of said outer fluid between said pairs of nested ducts connected by this spacer in a direction having an angle of between 0° and 90° with respect to said longitudinal direction (70).
6. Heat exchanger according to any of claims 1 to 5, characterized in that at least one heat exchange tube (31) comprises at least one pair of nested ducts, the ducts of which are connected to one another by a connecting rod which extends in the intermediate channel between the inner duct and the outer duct.
7. Heat exchanger according to any of claims 1 to 6, characterized in that at least one heat exchange tube (31) comprises at least one pair of nested cylindrical ducts (32; 33).
8. Heat exchanger according to any of claims 1 to 7, characterized in that at least one heat exchange tube (31) comprises at least one pair of concentric nested ducts.
9. Heat exchanger according to any of claims 1 to 8, characterized in that it further comprises a casing housing said heat exchange tubes, said casing delimiting the fluid circulation chamber (20).
10. System for cooling a fluid exhibiting a first temperature, referred to as hot fluid, with a fluid exhibiting a second temperature, referred to as cold fluid, comprising a hot fluid circuit suitable for being able to be supplied with hot fluid by a hot fluid source, and a cold fluid circuit suitable for being able to be supplied with cold fluid by a cold fluid source, characterized in that it further comprises a heat exchanger according to any of claims 1 to 9, said hot circuit supplying said intermediate channels and said cold circuit supplying said inner channels and said circulation chamber of said exchanger.
11. Cooling system according to claim 10, characterized in that said intermediate channels and said inner channels are supplied counter-currently by said hot and cold fluids, respectively.
12. Air conditioning system of a cabin of a transport vehicle comprising at least one air cooling system according to either claim 10 or claim 11.
13. Air, rail or automotive transport vehicle comprising at least one propulsion engine (61), a cabin and at least one air conditioning system for said cabin, characterized in that the air conditioning system of the cabin is an air conditioning system (62) according to claim 12.

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