EP4202342A1 - Heat exchanger, in particular tube bundle heat exchanger, for arrangement in a rotor with an axis of rotation - Google Patents

Abstract

Heat exchanger (7), in particular tube bundle heat exchanger, for arrangement in a rotor (1) with an axis of rotation (2), having: first heat exchange channels (15) for conducting a first heat exchange medium, in particular a liquid, second heat exchange ducts (12) for conducting a second heat exchange medium , in particular a gas, preferably an inert gas, wherein the second heat exchange channels (12), based on the assembled state of use, have at least one inner heat exchange channel located closer to the axis of rotation (2) and an outer heat exchange channel further away from the axis of rotation (2), an in Splitting element (17) widened, preferably conically widened, seen in the direction of flow of the second heat exchange medium, for supplying the second heat exchange medium from an inlet opening (17A) of the splitting element (17) into inflow openings (29) of the second heat exchange channels (12), seen in the direction of flow of the second heat exchange medium tapered, preferably substantially conically tapered, merging element (18) for discharging the second heat exchange medium from outflow openings (28) of the second heat exchange channels (12) into an outlet opening (18A) of the merging element (18), and a device (30) for equalizing the flow through the second heat exchange channels (12) which have a throttling element for differentially throttling an inner flow of the second heat exchange medium passing through the inner heat exchange channel and an outer flow of the second heat exchange medium through the outer heat exchange channel between the inlet opening (17A) of the dividing element (17) and the outlet opening (18A) of the combining element (18).

Description

• erste Wärmeaustauschkanäle zur Führung eines ersten Wärmeaustauschmediums, insbesondere einer Flüssigkeit,
• zweite Wärmeaustauschkanäle zur Führung eines zweiten Wärmeaustauschmediums, insbesondere eines Gases, bevorzugt eines Edelgases, wobei die zweiten Wärmeaustauschkanäle, bezogen auf den montierten Gebrauchszustand des Wärmetauschers, zumindest einen näher an der Drehachse gelegenen inneren
  Wärmeaustauschkanal und einen weiter von der Drehachse entfernten äußeren Wärmeaustauschkanal aufweisen,
• ein in Strömungsrichtung des zweiten Wärmeaustauschmediums gesehen aufgeweitetes, vorzugsweise konisch aufgeweitetes, Aufteilungselement zur Zuführung des zweiten
  Wärmeaustauschmediums von einer Eintrittsöffnung des Aufteilungselements in Einströmöffnungen der zweiten Wärmeaustauschkanäle, und
• ein in Strömungsrichtung des zweiten Wärmeaustauschmediums gesehen verjüngtes, vorzugsweise im Wesentlichen konisch verjüngtes, Zusammenführungselement zur Ableitung des zweiten Wärmeaustauschmediums von Ausströmöffnungen der zweiten Wärmeaustauschkanäle in eine Austrittsöffnung des Zusammenführungselements.

The invention relates to a heat exchanger, in particular a shell-and-tube heat exchanger, for use in a rotor with an axis of rotation, comprising:

• first heat exchange channels for conducting a first heat exchange medium, in particular a liquid,
• second heat exchange channels for conducting a second heat exchange medium, in particular a gas, preferably an inert gas, the second heat exchange channels, based on the assembled state of use of the heat exchanger, at least one inner one located closer to the axis of rotation
  have a heat exchange channel and an outer heat exchange channel further away from the axis of rotation,
• a dividing element which is widened, preferably conically widened, as seen in the direction of flow of the second heat exchange medium, for supplying the second
  Heat exchange medium from an inlet opening of the dividing element into inflow openings of the second heat exchange channels, and
• a merging element that is tapered, preferably substantially conically tapered, as seen in the direction of flow of the second heat exchange medium, for discharging the second heat exchange medium from outflow openings of the second heat exchange channels into an outlet opening of the merging element.

• eine Drehachse,
• einen Wärmetauscher.

The invention also relates to a rotor, in particular a rotary heat pump, having:

• an axis of rotation,
• a heat exchanger.

• Rotieren des Rotors um eine Drehachse,
• Führung des ersten Wärmeaustauschmediums entlang von ersten Wärmeaustauschkanälen eines Wärmetauschers,
• Führung eines zweiten Wärmeaustauschmediums entlang von zweiten Wärmeaustauschkanälen des Wärmetauschers in unterschiedlichen Abständen zur Drehachse des Rotors.

Finally, the invention relates to a method for heat exchange between a first heat exchange medium, in particular a liquid, and a second heat exchange medium, in particular a gas, preferably an inert gas, inside a rotor, with the steps:

• rotating the rotor around an axis of rotation,
• Guiding the first heat exchange medium along first heat exchange channels of a heat exchanger,
• Guide a second heat exchange medium along second heat exchange channels of the heat exchanger in different distances to the axis of rotation of the rotor.

From the WO2015/103656 a rotary heat pump is known in which the centrifugal acceleration of the rotor is used to generate different pressure or temperature levels. Heat at a high temperature is extracted from the compressed working medium and heat at a comparatively low temperature is supplied to the expanded working medium. For this purpose, the rotary heat pump has internal heat exchangers and external heat exchangers, which are arranged essentially parallel to the axis of rotation of the rotor. The inner heat exchangers are designed for lower temperature heat exchange and the outer heat exchangers for higher temperature heat exchange.

In addition, tube bundle heat exchangers are often used in stationary applications, in which the working medium flows through a bundle of tubes that is arranged inside a cylindrical housing shell. The heat exchange medium flows through the jacket space in loops that are formed by baffles. This type of heat exchanger promises particularly good heat transfer between the two media. In the case of stationary applications of such shell-and-tube heat exchangers, the incoming flow of the working medium is fanned out symmetrically to the main flow direction in order to divide the working medium accordingly among the individual tubes.

However, when attempting to use the known tube bundle heat exchangers with a rotor, in particular with a rotary heat pump, it has been shown that the heat transfer between the media falls well short of expectations.

The object of the present invention is therefore to alleviate or eliminate the disadvantages of the prior art. The aim of the invention is preferably to create a heat exchanger which, when used in a rotor, has a high level of efficiency.

This object is achieved by a heat exchanger according to claim 1, a rotor according to claim 8 and a method according to claim 13 solved. Preferred embodiments are given in the dependent claims.

According to the invention, a device for equalizing the flow through the second heat exchange channels is provided. This device has a throttle element which is designed to direct an inner flow of the second heat exchange medium passing through the inner of the second heat exchange channels and an outer flow of the second heat exchange medium through the outer of the second heat exchange channels between the inlet opening of the dividing element and the outlet opening of the combining element throttle.

For purposes of this disclosure, references to location and direction relate to the intended use of the heat exchanger as part of a rotor. "Front" and "rear" refer to the flow direction of the second heat exchange medium. "Radial" and "axial" refer to the axis of rotation of the rotor. "Inside" means closer to the axis of rotation of the rotor. "Outside" means farther from the axis of rotation. The distances refer to the radial distances from the axis of rotation.

Thus, the invention is based on the surprising finding that the heat exchanger cannot be operated effectively under the action of centrifugal acceleration by evenly dividing the second heat exchange medium. The invention solves this problem in that the different pressure differences of the partial flows of the second heat exchange medium flowing at different distances from the axis of rotation between the inlet opening of the dividing element and the outlet opening of the combining element are at least partially, preferably essentially completely, compensated. Advantageously, it can be achieved in this way that the flow through the second heat exchange channels is essentially uniform.

Extensive flow analyzes have shown that the main reason for the different pressure differences of the partial flows is that the outer flow in the dividing element first flows outwards and is compressed due to centrifugal force before the outer flow along the outer of the second heat exchange channels heats up with the first Exchanges heat exchange medium and then flows inwardly towards the outlet opening in the merging element and is relaxed in the process; for the inner flow the sequence is reversed as the inner flow in the dividing element first flows inwards and is expanded due to centrifugal force, then exchanges heat with the first heat exchange medium along the inner of the second heat exchange channels before the inner flow in the combining element flows outwards to the exit opening is guided and compressed in the process.

When the second heat exchange medium gives off heat to the first heat exchange medium in the second heat exchange channels, the pressure difference is created by first compressing at low density before heat exchange, namely from the collected inflow of the second heat exchange medium via the inlet opening to the inflow opening of the outer heat exchange channel, then heat dissipation takes place in the outer heat exchange channel, as a result of which the temperature of the second heat exchange medium drops and thus—in the case of a substantially isobaric heat exchange—the density increases; then the second heat exchange medium expands again with a comparatively high density, namely from the outflow opening of the outer heat exchange channel to the collection of the second heat exchange medium at the outlet opening. Because the second heat exchange medium compresses at low density (low pressure difference) and expands at high density (higher pressure difference), an additional pressure difference remains when considering this flow thread, which is required when flowing through the outer heat exchange channel. This would result in the second heat exchange medium preferring the inner one of the second heat exchange channels. When heat is supplied to the second heat exchange medium through the first heat exchange medium, the situation is reversed. Then the second would Heat exchange medium prefer the outer of the second heat exchange channels.

The invention now begins to equalize the additional pressure difference through the throttle element, which throttles the outer and inner flow to different degrees in a section between the inlet opening of the dividing element and the outflow opening of the combining element, i.e. causes different flow resistances.

If heat is dissipated from the second heat exchange medium to the first heat exchange medium in the second heat exchange channels, the throttle element is set up to throttle the inner flow more than the outer flow.

If heat is supplied from the first heat exchange medium to the second heat exchange medium in the second heat exchange channels, the throttle element is set up to throttle the outer flow more than the inner flow.

Thus, the throttling element is set up for asymmetrical throttling of the flow of the second heat exchange medium with respect to the central axis or axis of symmetry of the heat exchanger. With the aid of the throttle element, the second heat exchange medium is subjected to essentially the same pressure differences as it flows through the heat exchanger from the inlet to the outlet opening. Advantageously, it can be achieved in this way that the flow through the second heat exchange channels is essentially uniform, so that the second heat exchange medium has essentially the same average flow rate or essentially the same volume flow along the second heat exchange channels (provided that the second flow channels have, as is preferred, the same flow cross-section).

In a preferred embodiment, the heat exchanger is designed as a tube bundle heat exchanger. The tube bundle heat exchanger has a tube bundle with a plurality of tubes, preferably each with a substantially circular cross section, which enclose the second heat exchange channels. The pipes preferably extend parallel to one another. The tube bundle can be arranged within a preferably cylindrical housing. The first heat exchange medium is guided through first heat exchange channels extending inside the housing. Deflection elements for the first heat exchange medium are preferably provided within the housing. The deflection elements are preferably arranged essentially perpendicular to the tubes. The deflection elements preferably leave recesses free for the first heat exchange medium in the interior of the housing, with the recesses preferably being arranged alternately on opposite sides. As a result, the first heat exchange medium is guided in loops through the interior of the housing, the first heat exchange medium flowing in sections transversely to the tubes with the second heat exchange channels.

In a first preferred embodiment, the throttle device has a throttle diaphragm with throttle openings, with a throttle opening further away from the axis of rotation and a throttle opening located closer to the axis of rotation being of different sizes. The throttle orifice can be arranged in front of the inflow openings, in particular immediately in front of the inflow openings, or after the outflow openings, in particular immediately after the outflow openings. In an embodiment for dissipating heat from the second heat exchange medium, the throttle opening that is further away from the axis of rotation is larger than the throttle opening that is closer to the axis of rotation. In an embodiment for supplying heat to the second heat exchange medium, the throttle opening that is further away from the axis of rotation is smaller than the throttle opening that is closer to the axis of rotation. The advantage of this design of the throttle element is the simple structural implementation. Furthermore, the heat exchanger can be set to a specific operating point by simply replacing the restrictor orifice.

The throttle orifice is preferably arranged in front of the second heat exchange channels in such a way that the second heat exchange medium is fed to exactly one of the second heat exchange channels via the throttle openings.

Alternatively, the throttle orifice can be arranged after the second heat exchange channels in such a way that the second heat exchange medium is discharged from each of the second heat exchange channels through exactly one throttle opening.

In the following, preferred embodiments of the restrictor orifice are described using an embodiment for dissipating heat from the second heat exchange medium along the second heat exchange channels. The principle can be transferred accordingly to the case of supplying heat to the second heat exchange medium if greater throttling is provided, here by smaller throttling openings, with the distance to the axis of rotation to the outside.

The throttle orifice preferably has at least one first throttle opening at a first distance from the axis of rotation and at least one second throttle opening at a second distance from the axis of rotation of the rotor, the second distance being greater than the first distance and the second throttle opening being greater than the first throttle opening. The throttle orifice preferably has at least one third throttle opening at a third distance from the axis of rotation, which is greater than the second distance, the at least one third throttle opening being greater than the at least one second throttle opening. The throttle orifice preferably has at least one fourth throttle opening at a fourth distance from the axis of rotation, which is greater than the third distance, the at least one fourth throttle opening being greater than the at least one third throttle opening. Of course, the throttle orifice can have further throttle openings at greater distances from the axis of rotation of the rotor, with throttle openings further away from the axis of rotation being larger in each case than throttle openings located closer to the axis of rotation.

In a preferred embodiment, the heat exchanger comprises a plurality of rows of second heat exchange channels, the second heat exchange channels of each row being at substantially the same distance from the axis of rotation of the rotor. Correspondingly, the orifice plate preferably has a plurality of rows each with a plurality of throttle openings, one row further away from the axis of rotation and one closer to the axis of rotation located row have differently sized throttle openings. In the case of heat dissipation, the row of orifices farther from the axis of rotation has larger orifices than the row of orifices closer to the axis of rotation.

Thus, a first row of first throttle openings, each essentially at the first distance from the axis of rotation, and a second row of second throttle openings, each essentially at the second distance from the axis of rotation, preferably also a third row of third throttle openings, each essentially at the third distance to the axis of rotation, preferably also a fourth row of fourth throttle openings, each essentially at a fourth distance from the axis of rotation, preferably also at least one further row of further throttle openings, each at a further distance from the axis of rotation.

In order to enable the second heat exchange medium to be fed into the individual second heat exchange channels, the dividing element is arranged in front of the second heat exchange channels (seen in the direction of flow of the second heat exchange medium), which is widened as seen in the direction of flow of the second heat exchange medium, i.e. is designed with an increasing cross section. The splitting element enables the splitting of the flow of the second heat exchange medium at the inlet of the heat exchanger into the individual flows within the second heat exchange channels. The dividing element is preferably widened conically.

In a second preferred embodiment, a flow grid is arranged within the dividing element, the flow grid having individual dividing channels which widen in the direction of flow, the dividing channels each having a starting section and an end section.

In a second embodiment of the throttle element, the beginning and/or end section of a distribution channel that is further away from the axis of rotation and the beginning and/or end section of one that is closer to the axis of rotation have Distribution channel on different flow cross sections. The advantage of this design is that the flow grid is generally useful for good distribution and flow guidance in order to keep pressure losses as small as possible. Advantageously, this flow grid can now also be designed as a throttle element, with which an asymmetrical widening of the cross section is achieved in order to compensate for the different pressure differences depending on the distance from the axis of rotation. The initial section connects to the inlet of the heat exchanger. The end section guides the second heat exchange medium to the inflow opening of the second heat exchange channel. In the case of heat dissipation from the second heat exchange medium to the first heat exchange medium, the beginning and/or end section of the dividing channel further away from the axis of rotation has a larger flow cross section than the beginning and/or end section of the dividing channel located closer to the axis of rotation.

The flow grid preferably has exactly one distribution channel for each second heat exchange channel, so that the second heat exchange medium is fed to exactly one of the second heat exchange channels via each distribution channel. The distribution channels are separated from one another by individual wall parts, with vertical and horizontal wall parts preferably being provided. On the one hand, the standing wall parts serve to ensure that there is an even distribution in the tangential direction (whereby the problem of different pressures described above does not occur here), but they also have the advantage that the horizontal wall parts, which are provided for the radial distribution of the flow, be supported against deflection under the action of centrifugal force.

In the following, preferred embodiments of the flow grid are described using an embodiment for dissipating heat from the second heat exchange medium along the second heat exchange channels. The principle can be transferred accordingly to the case of heat supply if greater throttling is provided with the distance to the axis of rotation to the outside.

The flow grid preferably has at least a first distribution channel at a first distance from the axis of rotation and at least one second distribution channel at a second distance from the axis of rotation of the rotor, the second distance being greater than the first distance and the beginning and/or the end section of the second distribution channel having a larger flow cross-section than the beginning - Has and/or end section of the first splitting channel. The flow grid preferably has at least one third distribution channel at a third distance from the axis of rotation, the third distance being greater than the second distance and the start and/or end section of the third distribution channel having a larger flow cross section than the start and/or end section of the second distribution channel has. The flow grid preferably has at least one fourth distribution channel at a fourth distance from the axis of rotation, the fourth distance being greater than the third distance and the beginning and/or end section of the fourth distribution channel having a larger flow cross section than the beginning and/or end section of the third distribution channel has. Of course, the flow grid can have further distribution channels at greater distances from the axis of rotation, with the flow cross section of the beginning and/or end section increasing with the distance from the axis of rotation.

The flow grid preferably has at least a first row with a plurality of individual, i.e. separate, first distribution channels essentially at the first distance from the axis of rotation and a second row with a number of second distribution channels essentially at the second distance from the axis of rotation, preferably also a third row with a number of third distribution channels in the Essentially at the third distance from the axis of rotation, preferably also a fourth row with a plurality of fourth distribution channels essentially at the fourth distance from the axis of rotation, preferably also further rows each with a plurality of further distribution channels.

In a first variant, the initial section of the distribution channel further away from the axis of rotation has a larger flow cross section than the initial section of the distribution channel located closer to the axis of rotation, the The end section of the distribution channel that is further away from the axis of rotation has essentially the same flow cross section as the end section of the distribution channel that is located closer to the axis of rotation. This embodiment is particularly advantageous for design reasons if the second heat exchange channels have the same flow cross sections. Thus, in this variant, the second heat exchange medium can flow asymmetrically into the flow grid, with the flow cross section increasing with the inflow with the distance from the axis of rotation. The outflow from the flow grid, on the other hand, can take place symmetrically, ie with essentially the same flow cross section.

In a second variant, the end section of the distribution channel further away from the axis of rotation has a larger flow cross-section than the end section of the distribution channel located closer to the axis of rotation, with the initial section of the distribution channel further away from the axis of rotation having essentially the same flow cross-section as the initial section of the channel closer to the Having axis of rotation located distribution channel. This design is structurally particularly simple. Thus, in this variant, the inflow into the flow grid can be symmetrical, but the outflow from the flow grid can be asymmetrical.

In a third variant, the initial section and the end section of the distribution channel further away from the axis of rotation each have a larger flow cross section than the initial section and the end section of the distribution channel located closer to the axis of rotation. With this variant, both the inflow into the flow grid and the outflow from the flow grid can take place asymmetrically, i.e. with a larger flow cross section with increasing distance from the axis of rotation.

The asymmetric distribution of the second heat exchange medium by means of the flow grid has the consequence that a flow of the second heat exchange medium close to the axis from the entry into the heat exchanger to the exit from the heat exchanger has a smaller flow cross section than one in sections off-axis flow of the second heat exchange medium flows through, whereby the off-axis flow is exposed to a higher pressure loss than the off-axis flow. In this way, the pressure difference between the second heat exchange channel near the axis and the second heat exchange channel remote from the axis is at least partially, preferably substantially completely, compensated.

In addition, a flow grid can be arranged within the merging element, the flow grid within the merging element having individual merging channels that taper in the direction of flow, the merging channels each having a starting section (on the side of the outflow openings of the second heat exchange channels) and an end section (on the side of the outflow openings side facing away) have. To form the throttle element, the beginning and/or end section of a merging channel further away from the axis of rotation and the beginning and/or end section of a merging channel closer to the axis of rotation have different flow cross sections.

In a third preferred embodiment, the device for equalizing the flow through the second heat exchange channels has turbulators, in particular spiral turbulators, within the second heat exchange channels, with a turbulator further away from the axis of rotation and a turbulator closer to the axis of rotation causing different pressure losses. In the case of heat dissipation from the second heat exchange medium along the second heat exchange channels, the turbulator that is further away from the axis of rotation causes a lower pressure loss than the turbulator that is closer to the axis of rotation

For this purpose, the turbulator further away from the axis of rotation and the turbulator located closer to the axis of rotation can have different spiral lengths. In the case of heat dissipation from the second heat exchange medium along the second heat exchange channels, the turbulator that is further away from the axis of rotation can have a greater pitch than the turbulator that is closer to the axis of rotation.

The advantage of the turbulators compared to the previously described embodiments of the throttle device is that not only the pressure loss in the second heat exchange channels with different distances to the axis of rotation can be set differently in order to achieve a uniform flow through the second flow channels, but also the heat transfer by an increased Turbulence in heat transfer is increased.

In a fourth embodiment, the outer and inner of the second heat exchange channels have different flow cross-sections, in the case of tubes with circular cross-sections different diameters, to form the throttle member.

In a preferred application, a rotor, in particular a rotary heat pump, is provided with the heat exchanger in one of the previously described embodiments.

In a first preferred embodiment, a central or symmetrical axis of the heat exchanger is arranged at a radial distance from the axis of rotation, i.e. with an axial offset.

In a second preferred embodiment, the central axis of the heat exchanger is arranged substantially in line with the axis of rotation. In this case, too, the second heat exchange channels are at different distances from the axis of rotation.

In the case of the rotor, the second heat exchange channels preferably extend essentially parallel and at different radial distances from the axis of rotation. The first heat exchange channels can, as is usual in tube bundle heat exchangers, extend in sections essentially perpendicularly to the second heat exchange channels.

In a preferred embodiment, the rotor has a compressor unit in which the second heat exchange medium for pressure increase due to centrifugal force from the The axis of rotation is carried away, and an expansion unit in which the second heat exchange medium is guided toward the axis of rotation for pressure reduction due to the centrifugal force.

In this embodiment of the rotor, at least one heat exchanger that is on the inside with respect to the axis of rotation and at least one heat exchanger that is on the outside with respect to the axis of rotation are preferably provided. Depending on the design, the outer heat exchanger and/or the inner heat exchanger can be designed according to one of the above embodiments of the heat exchanger.

• Rotieren des Rotors um eine Drehachse,
• Führung des ersten Wärmeaustauschmediums entlang von ersten Wärmeaustauschkanälen eines Wärmetauschers,
• Führung des zweiten Wärmeaustauschmediums entlang von zweiten Wärmeaustauschkanälen des Wärmetauschers in unterschiedlichen Abständen zur Drehachse des Rotors,
• Vergleichmäßigung der Durchströmung der zweiten Wärmeaustauschkanäle durch unterschiedliche Drosselung einer inneren Strömung des zweiten Wärmeaustauschmediums näher an der Drehachse und einer äußeren Strömung des zweiten Wärmeaustauschmediums weiter von der Drehachse entfernt.

In the method according to the invention for heat exchange between a first heat exchange medium, in particular a liquid, and a second heat exchange medium, in particular a gas, preferably an inert gas, inside a rotor, with the steps:

• rotating the rotor around an axis of rotation,
• Guiding the first heat exchange medium along first heat exchange channels of a heat exchanger,
• Guiding the second heat exchange medium along second heat exchange channels of the heat exchanger at different distances from the axis of rotation of the rotor,
• Equalizing the flow through the second heat exchange channels by different throttling of an inner flow of the second heat exchange medium closer to the axis of rotation and an outer flow of the second heat exchange medium further away from the axis of rotation.

In a preferred embodiment, heat is removed from the second to the first heat exchange medium along the second heat exchange channels, with the inner flow of the second heat exchange medium being throttled more than the outer flow of the second heat exchange medium.

The invention is explained below with reference to preferred exemplary embodiments which are illustrated in the drawings.

1 shows a rotor 1, which in the embodiment shown designed as a device for converting mechanical energy into thermal energy (and vice versa). This device is operated in particular as a rotary heat pump. The rotor 1 has an axis of rotation 2, which is horizontal during operation, for example, about which the rotor 1 is rotated with the aid of a motor (not shown). The rotor 1 has a compressor unit 3 in which a working medium is conducted away from the axis of rotation 2 to increase the pressure due to the centrifugal force. In addition, the rotor 1 has an expansion unit 4 in which the working medium is guided towards the axis of rotation 2 to reduce the pressure. The working medium is preferably conducted within the rotor 1 in a closed circuit. In addition, the rotor 1 has a plurality of internal heat exchangers 5 (low-pressure heat exchangers) and a plurality of external heat exchangers 6 (high-pressure heat exchangers). In the inner 5 and outer 6 heat exchangers, heat exchange is carried out between a first heat exchange medium and a second heat exchange medium, namely the working medium. Such a device - but with different types of heat exchangers - is for example in WO2015/103656 shown.

Figure 2A shows a heat exchanger 7, also referred to as a heat exchanger, in an embodiment which can be implemented in the inner 5 and/or the outer heat exchanger 6. The heat exchanger 7 is described below as an example for use as an external heat exchanger 6, ie as a high-pressure heat exchanger. The heat exchanger 7 has an inlet element 8, via which the second heat exchange medium, ie the working medium, is fed to the heat exchanger 7, and an outlet element 9 which the second heat exchange medium leaves the heat exchanger 7.

In the embodiment shown, the heat exchanger 7 is designed as a tube bundle heat exchanger. The tube bundle heat exchanger has a cylindrical housing 10 in which a tube bundle is arranged. The tube bundle comprises elongate tubes 11 arranged parallel and spaced apart in the radial and circumferential directions. Inside, the tubes 11 enclose second heat exchange channels 12 for the second heat exchange medium. The tubes 11 are on opposite ends are each held in a tube sheet in the form of a base plate 11A (cf. Figure 2B ). The first heat exchange medium is guided into the interior of the housing 10 via a feed 13 and, after the heat exchange with the second heat exchange medium, is discharged from the housing 10 via a discharge line 14 . Inside the housing 10, the first heat exchange medium flows in the first heat exchange channels 15, which are designed with the aid of deflection elements 16 in such a way that the first heat exchange medium flows alternately in opposite directions across the tubes 11, ie alternately downwards and upwards in the position shown. flows. In between, the first heat exchange medium is deflected into the next channel by means of the deflection elements 16 .

How out Figure 2A further evident, the heat exchanger 7 between the inlet element 8 and the inlet side of the housing 10 on a dividing element 17 with an inlet opening 17A, which is widened as seen in the direction of flow of the second heat exchange medium. In addition, the heat exchanger 7 has a merging element 18 with an outlet opening 18A between the outlet element 9 and the outlet side of the housing 10 for merging the individual flows of the second heat exchange medium after flowing through the second heat exchange channels 12 . The combining element 18 tapers in the direction of flow of the second heat exchange medium.

Figure 2B 12 shows the heat exchanger 7 in a simplified manner, the inflow and distribution of the gas to the individual second heat exchange channels 12 within the housing 10 being illustrated by arrows.

The design of the heat exchanger 7 as a tube bundle heat exchanger is fundamentally very advantageous for use with the rotor 1 . It is essential, however, that the flow through the second heat exchange channels 12 is uniform in order to use the heat transfer surface effectively.

How out 3 apparent, it would be obvious that entering the heat exchanger 7 flow of the second Heat exchange medium, cf. Arrow 20, evenly to the discrete second flow channels 12, ie the tube bundle tubes, by fanning out. For this purpose, a flow grating 21 can be arranged inside the dividing element 17, which has individual dividing channels 22 which widen continuously along the flow grating 21. The splitting channels 22 are according to FIG 3 identically designed in order to achieve an even distribution.

Surprisingly, however, it has been shown that in the rotating state of the rotor 1 with high centrifugal acceleration, a number of phenomena occur which prevent a uniform flow through simply fanning out the incoming flow of the second heat exchange medium. The reason that was recognized was that different densities occur when the second heat exchange medium, here the gas, enters and exits at the different radial distances from the center of rotation of the discrete second flow channels 12 .

How out 4 Based on a schematic representation of the heat exchanger 7 when used as an external (high-pressure) heat exchanger 6, during operation heat is to be transferred from the second heat exchange medium, hereinafter also referred to as gas, to the first heat exchange medium, hereinafter also referred to as liquid or water referred to, are transmitted. On the right side the inflow takes place at relatively high temperature and on the left side the outflow at relatively low temperature after heat transfer. This results in a higher density on the outflow side than on the inflow side.

• Mittlerer Radius zur Rotationsachse: 900 mm
• Radiale Erstreckung des Wärmetauschers 7 (vom innersten der zweiten Wärmeaustauschkanäle 12 zum äußersten der Wärmeaustauschkanäle 12): 100mm
• Mittlerer Druck im Wärmetauscher: 120bar
• Mittlere Temperatur: 400K
• Gas: Krypton

To illustrate the technical effect, the following assumptions and simplifications are made for a model calculation:

• Average radius to the axis of rotation: 900 mm
• Radial extension of the heat exchanger 7 (from the innermost of the second heat exchange channels 12 to the outermost of the heat exchange channels 12): 100 mm
• Medium pressure in the heat exchanger: 120bar
• Average temperature: 400K
• Gas: krypton

If the flow of the gas, which is assumed to be ideal, i.e. without considering real gas properties, takes place only under the acceleration of gravity, and the heat exchanger is aligned in such a way that the acceleration of gravity has the same direction as the centrifugal acceleration, then the pressure difference between the outermost flow channel and the innermost flow channel is 0.14 mbar and is not taken into account due to the minimal effect.

figure 5 shows a roughly calculated pressure difference between the flow channels ("outside" - arrow 23 in 4 ; "inside" - arrow 24 in 4 ) in revolutions per minute (RPM), showing the effect of rotation on the heat exchanger 7. The radial distance of the outermost channel from the axis of rotation 2 is indicated by arrow 25, the radial distance of the innermost channel from the axis of rotation 2 is indicated by arrow 26. Arrow 27 shows the main flow direction of the gas. At a speed of rotor 1 of 1800 rpm, this difference is 0.46 bar and is therefore greater by a factor of about 3300 (corresponding to the ratio of the accelerations) than under gravitational acceleration. This results in the gas preferring the inner channels unless other measures are taken, since the gas in the inner areas experiences an increase in pressure, with the gas experiencing a pressure reduction through the outermost channel. Backflows can also occur, so that the gas flows from right to left on the inside and from left to right on the outside. The consequence of this is that more flow energy is required and a smaller effective heat exchanger surface is available, since for the most part only the inner area of the heat exchanger is used.

6 and 7 show a first embodiment of the heat exchanger 7 according to the invention for the case of the outer heat exchanger 6, with only the differences from the previous versions being described below.

In this embodiment, a device 30 for equalizing the flow through the second Heat exchange channels 12 are provided, with which different pressure differences of the second heat exchange medium are compensated, which are caused by the different radial distances of the second heat exchange channels 12 to the axis of rotation 2 of the rotor 2.

In the embodiment shown, a throttling device for different throttling of the discrete second heat exchange ducts 12 is provided as a device 30 for equalizing the flow through the second heat exchange ducts 12 . A flow of the second heat exchange medium closer to the axis of rotation 2, i.e. having a smaller radial distance, is throttled more than a flow of the second heat exchange medium further away from the axis of rotation 2, i.e. having a greater radial distance.

In execution according to 6 and 7 the throttle device has a disk-shaped throttle orifice 31 that is circular as seen in the direction of flow of the second heat exchange medium and has a large number of circular throttle openings 32 which are arranged directly in front of the inflow openings 29 of the second heat exchange channels 12 . The throttle openings 32 are arranged in rows, with the diameter of the throttle openings 32 increasing from row to row outwards, ie away from the axis of rotation 2 . Within a row, the throttle openings 32 have the same diameter.

In execution according to 8 a (relative to the central axis 36 of the heat exchanger 7) asymmetrically designed flow grid 21 is provided as a device 30 for equalizing the flow through the second heat exchange channels. The dividing channels 22 of the flow grid 21 each have a beginning section 22A and an end section 22B. In the embodiment shown, the flow cross-section of the initial sections 22A increases with distance from the axis of rotation 2 . The end sections 22B, on the other hand, have the same flow cross sections. Between the beginning sections 22A and the end sections 22B, middle sections 22C extend, which form a continuous transition from the Make beginning sections 22A to end sections 22B.

In execution according to 9 Spiral turbulators 33 are inserted into the second heat exchange passages 12. Various spiral turbulators 33 are provided to form the device 30 , which cause lower pressure losses in the second heat exchange medium the further away the spiral turbulators 33 are from the axis of rotation 2 . For this purpose, a spiral turbulator 33 that is further away from the axis of rotation 2 can have a greater spiral length, see arrow 34, than a turbulator 33 that is closer to the axis of rotation 2, see arrow 35.

Reference number list:

1

rotor

2

axis of rotation

3

compressor unit

4

relaxation session

5

internal heat exchangers

6

external heat exchangers

7

heat exchanger

8th

entry element

9

exit element

10

Housing

11

Tube

11A

tube sheet

12

second heat exchange channels

13

feeding

14

derivation

15

first heat exchange channels

16

deflection elements

17

splitting element

17A

entry opening

18A

exit port

18

merge element

20

Arrow

21

flow grid

22

split channels

22A

beginning section

22B

middle section

22C

end section

23

Arrow

24

Arrow

25

Arrow

26

Arrow

27

Arrow

28

outflow openings

29

inflow openings

30

Device for smoothing the flow

31

orifice plate

32

throttle openings

33

turbulators

34

Arrow

35

Arrow

36

central axis

Claims (13)

Heat exchanger (7), in particular tube bundle heat exchanger, for arrangement in a rotor (1) with an axis of rotation (2), having: first heat exchange channels (15) for conducting a first heat exchange medium, in particular a liquid, second heat exchange ducts (12) for conducting a second heat exchange medium, in particular a gas, preferably an inert gas, the second heat exchange ducts (12), based on the assembled state of use, having at least one inner heat exchange duct located closer to the axis of rotation (2) and one further from the axis of rotation (2) have remote outer heat exchange channel, a dividing element (17) which is widened, preferably conically widened, as seen in the direction of flow of the second heat exchange medium, for feeding the second heat exchange medium from an inlet opening (17A) of the dividing element (17) into inflow openings (29) of the second heat exchange channels (12), a merging element (18) which is tapered, preferably substantially conically tapered, as seen in the direction of flow of the second heat exchange medium, for discharging the second heat exchange medium from outflow openings (28) of the second heat exchange channels (12) into an outlet opening (18A) of the merging element (18), marked by a device (30) for equalizing the flow through the second heat exchange channels (12), which has a throttle element for different throttling of an inner flow of the second heat exchange medium passing through the inner of the second heat exchange channels (12) and an outer flow passing through the outer of the second heat exchange channels (12). of the second heat exchange medium between the inlet opening (17A) of the dividing element (17) and the outlet opening (18A) of the combining element (18). Heat exchanger (7) according to Claim 1, characterized in that that the throttle element has a throttle orifice (31) with throttle openings (32), preferably before the inflow openings (29) or after the outflow openings (28), with a throttle opening (32) further away from the axis of rotation (2) and one closer to the Axis of rotation (2) located throttle opening (32) are of different sizes. Heat exchanger (7) according to Claim 2, characterized in that the throttle orifice (31) has a number of rows, each with a number of throttle openings (32), with a row further away from the axis of rotation (2) and a row closer to the axis of rotation (3). have differently sized throttle openings (32). Heat exchanger (7) according to one of Claims 1 to 3, characterized in that the dividing element (17) has a flow grid (21) with individual dividing channels (22) which widen in the direction of flow of the second heat exchange medium, the dividing channels (22) each having one having a beginning portion (22A) and an ending portion (22B). Heat exchanger (7) according to Claim 4, characterized in that to form the throttle element, the start (22A) and/or end section (22B) of a distribution channel (22) further away from the axis of rotation (2) and the start (22A) and /or end section (22B) of a distribution channel (22) located closer to the axis of rotation (2) have different flow cross sections. Heat exchanger (7) according to one of Claims 1 to 5, characterized in that turbulators (33), in particular spiral turbulators, are provided within the second heat exchange channels (12) to form the throttle element, with a further from the axis of rotation (2) remote The turbulator (33) and a turbulator (33) located closer to the axis of rotation (2) cause different pressure losses. Heat exchanger (7) according to Claim 6, characterized in that the spiral turbulator which is further away from the axis of rotation (2). (33) and the spiral turbulator (33) located closer to the axis of rotation (2) have different spiral lengths. Rotor (1), in particular rotary heat pump, having:
an axis of rotation (2),
a heat exchanger (7) according to any one of claims 1 to 7. Rotor (1) according to Claim 8, characterized in that the second heat exchange channels (12) extend essentially parallel to the axis of rotation (2). Rotor (1) according to Claim 8 or 9, characterized by : a compressor unit (3) in which the second heat exchange medium is conducted away from the axis of rotation (2) to increase the pressure, an expansion unit (4) in which the second heat exchange medium is guided towards the axis of rotation (2) for pressure reduction. Rotor (1) according to one of Claims 8 to 10, characterized by :
an internal heat exchanger (5) with respect to the axis of rotation (2) and an external heat exchanger (6) with respect to the axis of rotation (2). Rotor (1) according to Claim 11, characterized in that the outer (6) heat exchanger (5) is designed according to one of Claims 1 to 7, the throttle element for throttling the inner flow of the second heat exchange medium passing through the inner heat exchange channel to a greater extent than the den outer flow of the second heat exchange medium passing through the outer heat exchange channel. Method for heat exchange between a first heat exchange medium, in particular a liquid, and a second heat exchange medium, in particular a gas, preferably an inert gas, inside a rotor (1), with the steps: rotating the rotor (1) about an axis of rotation (2), Guidance of the first heat exchange medium along first Heat exchange channels (15) of a heat exchanger (7), Guidance of a second heat exchange medium along second heat exchange channels (12) of the heat exchanger (7) at different distances from the axis of rotation (2) of the rotor (1), with heat exchange taking place along the first (15) and second heat exchange channels (12) between the first and the second heat exchange medium takes place, marked by Equalizing the flow through the second heat exchange channels (12) by different throttling of an inner flow of the second heat exchange medium closer to the axis of rotation (2) and an outer flow of the second heat exchange medium further away from the axis of rotation (2).

Images