Heat exchanger for a high inflow velocity

Abstract

The invention relates to a heat exchanger (10) for cooling a hot fluid, in particular an exhaust gas or a fuel-cell cooling fluid, by means of a cooling fluid which is at a lower temperature than the hot fluid and which has a high flow velocity, comprising a high-temperature grille (30) for guiding the hot fluid and a low-temperature grille (20) for guiding the cooling fluid. According to the invention, a heat exchanger which can improve a transfer of heat despite a high-velocity inflowing fluid and / or which can reduce the required installation space is created in that a diffuser region (24) for decelerating the cooling fluid is arranged in at least one first low-temperature channel (21), through which the cooling fluid flows, of the low-temperature grille (20), and in that the diffuser region (24) and a first high-temperature channel (31), through which the hot fluid flows, of the high-temperature grille (30) have at least one shared wall (40) for heat transfer.

Description

[0001] Heat exchanger for high flow velocity

[0002] The invention relates to a heat exchanger for cooling a hot fluid, in particular an exhaust gas or a fuel cell cooling fluid, by means of a cooling fluid having a lower temperature and a high flow velocity relative to the hot fluid, comprising a high-temperature grid for guiding the hot fluid, a low-temperature grid for guiding the cooling fluid.

[0003] There is a constant effort to produce aircraft engines with lower emissions. The technologies conventionally used for this purpose have almost reached their limits. Only small steps are still possible, but a major leap was recently achieved through the use of gearboxes to enable the use of slower fans with the simultaneous use of high-speed turbines. To further reduce emissions and increase efficiency, work is currently underway on water recovery systems that rely on the use of heat exchangers and water recovery systems to recover water from the exhaust gas. Previous systems relied on solutions that provided the heat exchanger outside the engine. The frontal surfaces, referred to below as inflow surfaces, of these heat exchangers on the cooling air side would be much larger than, for example, the cross-sectional area of ​​the engine into which they are to be integrated.For this reason, integrating such heat exchangers into an aircraft, based on the principle shown in Fig. 1, is difficult or even impossible. The necessary surface area expansion in the inlet channel to reduce speed would require very large installation lengths. Furthermore, the required inlet area of ​​the heat exchangers would result in an increase in the aircraft's displacement cross-section, thus significantly increasing pressure and form drag.

[0004] The need for cooling is also high in the field of fuel cells, an emerging technology in aircraft engines. Currently available solutions can be further optimized, making a heat exchanger with a small footprint advantageous. However, heat exchangers that operate at high flow velocities of the cooling fluid while requiring less space can also be advantageous in other areas.

[0005] In this context, a high flow velocity is understood to be a flow velocity typically encountered in the aviation sector. A velocity >50 m / s can therefore usually be assumed. If a heat exchanger is located in the bypass flow of an engine, significantly higher flow velocities can occur, in the range of Mach 0.4 to Mach 0.5.

[0006] It is an object of the invention to provide a heat exchanger and a heat exchanger arrangement which improve heat transfer through a rapidly flowing fluid and / or reduce the required installation space.

[0007] This object is achieved by a heat exchanger having the features of independent claim 1 and by a heat exchanger arrangement having the features of independent claim 6.

[0008] A heat exchanger according to the invention for cooling a hot fluid by means of a cooling fluid having a lower temperature relative to the hot fluid and a high flow velocity comprises a high-temperature grid for guiding the hot fluid and a low-temperature grid for guiding the cooling fluid. According to the invention, a diffuser region for delaying the incoming fluid is arranged in at least one (preferably in many) first low-temperature channel of the low-temperature grid through which the cooling fluid flows. Furthermore, the invention provides that the diffuser region and a first high-temperature channel of the high-temperature grid through which the hot fluid flows have at least one common wall for heat transfer.Due to the common wall, the diffuser area is already involved in the heat transfer, so that valuable installation space can be used thermally and the size of the heat exchanger can be reduced.

[0009] According to one embodiment of the invention, the low-temperature channel can have a deflection region which is arranged upstream of the diffuser region and in which the cooling fluid is deflected but not yet decelerated. In other words, the cooling fluid can initially be deflected with a substantially constant or decreasing cross-sectional area before entering the diffuser region, in which the cross-sectional area of ​​the low-temperature channel increases. This enables a change in the direction of the cold flow from the approach angle to the main inclination angle of the low-temperature channel even before entering the diffuser region. Preferably, the cooling fluid can be accelerated in the deflection region, i.e. the cross-sectional area of ​​the deflection region decreases in the flow direction. In a preferred development, the diffuser region can have substantially flat side walls, since the deflection already occurs in the deflection region.

[0010] The heat exchanger can also be designed as a condenser for separating liquids from a gas flowing through the condenser as the hot fluid. The hot fluid can in particular be an exhaust gas from a turbomachine such as a gas turbine or an aircraft engine. The hot fluid can also be a coolant of a fuel cell, preferably to support the thermal management of a fuel cell and to be able to cool a fuel cell more efficiently. In particular, compressed air is preferably provided as the cooling fluid. The deceleration of the incoming cooling fluid represents a reduction in the flow velocity, so that a cooling fluid flowing in at high velocity can advantageously be slowed to a reduced speed for the greatest possible absorption of heat, thereby reducing pressure losses.The high-temperature grid is formed, in particular, by a plurality of high-temperature channels, which comprise at least the first high-temperature channel. Furthermore, the low-temperature grid is preferably formed by a plurality of low-temperature channels, which comprise at least the first low-temperature channel. Preferably, the high-temperature grid is arranged, at least in sections, in a cross-flow and / or counterflow configuration relative to the low-temperature grid. In a particularly preferred embodiment, the low-temperature channels and the high-temperature channels are arranged in a cross-flow configuration.

[0011] The diffuser region consists of one or more regions that extend a flow-through cross-sectional area of ​​the low-temperature grid in an inlet cross-section or a minimum cross-section, in particular a minimum inlet cross-section, of the diffuser region of the low-temperature channel, in particular of the plurality of low-temperature channels, to a downstream cross-section, in particular the main cross-section, of the low-temperature channel that is larger than the inlet cross-section. This reduces the flow velocity of the cooling fluid in each of these regions.

[0012] The high-temperature grid and the low-temperature grid each represent a flow space for a fluid, wherein the two grids, the high-temperature grid and the low-temperature grid, can preferably jointly consist of an integral grid body with common walls of the two grids or can have a grid body comprising common walls of the two grids. The high-temperature channels and the low-temperature channels are arranged in the grid body. The common walls preferably have at least a minimal distance between the two flow spaces transversely to a respective travel extension of the walls. It can further be provided that the walls have a constant wall thickness, at least in sections.

[0013] The common wall can be defined by its first wall side surface forming part of the low-temperature grid, and its second wall side surface facing away from the first wall side surface forming part of the high-temperature grid. The first wall side surface extends into the diffuser area. This advantageously increases the heat flow.

[0014] In a first embodiment, the heat exchanger is further developed such that the at least one common wall for forming the diffuser region in the first low-temperature channel has a convexly curved first diffuser section. Preferably, the common wall has an adjoining straight main section downstream in the low-temperature grid for forming a main region of the first low-temperature channel with a constant cross-section. This enables a change in the direction of the cold flow from the angle of incidence to the main angle of inclination of the low-temperature channel.

[0015] In a further preferred embodiment, a second common wall is arranged in the low-temperature channel opposite the first common wall, which second common wall borders a second high-temperature channel of the high-temperature grid in the diffuser region on the wall side facing away from the first low-temperature channel, wherein the second common wall in the diffuser region has a concavely curved, second diffuser section. According to one embodiment, a curvature of the convexly curved, first diffuser section can be smaller than a curvature of the second diffuser section, or vice versa. The diffuser region and thus the diffuser sections begin in particular at a narrowest cross-sectional area of ​​the low-temperature channel, if possible directly behind an inlet of the low-temperature channel.

[0016] Accordingly, in a preferred further embodiment, an inlet for diverting the cooling fluid into the diffuser region can be arranged upstream of the diffuser region in the flow direction of the cooling fluid. The inlet serves to direct the fluid from the flow channel into the low-temperature channel. In this case, an inlet surface facing away from the wind in the flow channel is advantageously elongated, while an opposite inlet surface facing the wind is bent by approximately 180°. At the end of the bend of the inlet surface facing the wind in the low-temperature channel, the smallest cross-sectional area of ​​the low-temperature channel is preferably located. At the other end of the bend, the inlet surface facing the wind merges into an inlet surface of an adjacent low-temperature channel facing away from the wind. In the flow direction in the low-pressure channel, the diffuser region ideally follows the inlet to slow the flow.This advantageously aligns the flow direction of the cooling fluid with the flow direction in the diffuser area and reduces air resistance.

[0017] In order to achieve the most ideal flow through the low-pressure channel, in a further embodiment, an outlet area with an outlet nozzle for accelerating the cooling fluid is arranged downstream of the diffuser area in the heat exchanger.

[0018] A further aspect of the invention is a heat exchanger arrangement with a heat exchanger, in particular with a heat exchanger as described above, comprising a flow channel for the flow of the cooling fluid to the heat exchanger. The heat exchanger is arranged in the flow channel for guiding the cooling fluid, and the low-temperature grid and the high-temperature grid form a first heat exchanger module of the heat exchanger. According to the invention, a plurality of common walls jointly form a first inflow surface in the flow channel, which delimits the first heat exchanger module and is spanned by the common walls, wherein the inflow surface has an inflow angle between 0° and 45°, advantageously between 3° and 15°, to a main channel direction of the flow channel.Advantageously, this makes it possible to achieve a particularly uniform flow (with a constant flow velocity) through the heat exchanger and the individual low-temperature channels, resulting in a homogeneous flow in each of the low-temperature channels and thus, advantageously, a homogeneous heat flow from the hot fluid to the cooling fluid. The area of ​​the flow channel upstream of the heat exchanger can also be referred to as the inflow area, with the main channel direction in this inflow area and the inflow surface forming the inflow angle. Preferably, the inflow angle is constant along at least part of the extent of the inflow surface. In a supplementary or alternative embodiment, the inflow surface can be curved or angled, with the inflow angle then being able to assume correspondingly different values.The inflow surface results from a surface spanned by the heat exchanger, i.e., enveloping it. This surface borders the flow channel upstream and is an auxiliary construction for describing the boundaries of the heat exchanger. The inflow surface can be flat, curved, and / or twisted, particularly in sections, depending on the arrangement of the shared walls. Viewed in space, a flat inflow surface has linear contact with each shared wall. In a section through the heat exchanger, the contact is reduced to point contacts with the shared walls. If the inflow surface is curved, the contact expands accordingly.

[0019] In a particularly preferred embodiment of the flow channel, the cross-section of the flow channel decreases in the flow direction upstream of the inflow surface along the area occupied by the heat exchanger module. It can thus advantageously be provided that at a design point of the heat exchanger, which can be determined, for example, by a travel speed of the turbomachine surrounding the heat exchanger, the cooling fluid is sucked into the low-temperature grid in layers from one low-temperature channel to the next low-temperature channel. This is achieved in particular by the inlet cross-section of a first, in particular each, low-temperature channel being aligned with the main channel direction or being perpendicular to this. Preferably, a second inlet of a second low-temperature channel adjacent to the first low-temperature channel can be arranged offset.As a result, there are hardly any spatial flows along the flow in the flow channel, so that the heat exchanger arrangement works particularly efficiently.

[0020] In a preferred development of the heat exchanger arrangement, a main region of the low-temperature channel having an extension axis borders the diffuser region downstream, in particular directly, wherein the direction of the extension axis, in particular a direction of a traveling extension of the common wall in the main region, has a main inclination angle of between 0° and 60°, preferably between 30° and 55°, to the inflow surface of the heat exchanger. The extension axis of the main region is preferably a straight line and can run in particular parallel to an extension direction of the side surfaces of at least one of the common walls in the main region, in particular in the flow direction. The main region can preferably have a constant cross-sectional area normal to the extension axis along the extension axis.In the main region, a large part of the heat transfer takes place between the low-temperature grid and the high-temperature grid. Because the cross-sectional area is constant along the longitudinal extent, a uniform heat exchanger can be formed and advantageously contributes to the walls of the heat exchanger being at least largely identical and thus cost-effective. This design has a positive synergistic effect, particularly in a heat exchanger arrangement comprising a heat exchanger with a grid matrix of low- and high-temperature grids, whose low- and high-temperature channels are each uniformly formed at least along an extent of the heat exchanger. Furthermore, calculations have shown that the formation of main regions formed at an angle to the inflow surface, in particular at an angle to the main channel direction, can lead to high flow losses.This is advantageously avoided according to the invention by the delay in the diffuser.

[0021] In a further embodiment, the heat exchanger arrangement can be developed such that a plurality of common walls together form a first outflow surface in the flow channel, which delimits the first heat exchanger module and is spanned by the common walls, wherein the first outflow surface forms a first outflow angle between 0° and 45°, advantageously between 3° and 15°, to a main channel direction in the flow channel. In one advantageous embodiment, the outflow angle of a heat exchanger module corresponds to the inflow angle of this heat exchanger module. However, it can also be provided that the outflow angle is different from the inflow angle. In one advantageous embodiment, the outflow direction corresponds to the inflow direction and thus to the main channel direction.Preferably, the cross section of the flow channel increases in the flow direction behind the outflow surface along the area occupied by the heat exchanger module, in particular to the extent that the cross section of the flow channel has decreased in the flow direction in front of the inflow surface.

[0022] In addition, an embodiment of the heat exchanger arrangement can provide that the heat exchanger is formed from the first heat exchanger module and a further second heat exchanger module, that a further plurality of low-temperature channels form the second heat exchanger module and that a further plurality of common walls together form a second inflow surface in the flow channel which delimits the second heat exchanger module and is spanned by the common walls, wherein the second inflow surface forms a second inflow angle between 0° and -45°, advantageously between -3° and -15°, to a main channel direction of the flow channel.

[0023] In a preferred embodiment of the heat exchanger arrangement, the further plurality of common walls together form a second outflow surface in the flow channel which delimits the second heat exchanger module upstream, wherein the second outflow surface forms a second outflow angle between 0° and 45°, advantageously between 3° and 15°, to a main channel direction of the flow channel.

[0024] In a particularly preferred embodiment of the heat exchanger arrangement, it is provided that the first heat exchanger module and the second heat exchanger module are formed surface-symmetrically to a common surface lying between the first and second heat exchanger modules, which surface runs parallel to a main channel direction of the flow channel.

[0025] Furthermore, in a preferred embodiment, the heat exchanger arrangement can be further developed such that a portion of the flow channel forms a cold channel running past the heat exchanger. This advantageously allows only a portion of the available cooling fluid to be used for cooling. Particularly in an engine, the remaining air can thus be used without delay to generate thrust.

[0026] In a further aspect of the invention, a turbomachine with a bypass duct and a heat exchanger arrangement described above is provided, which is characterized in that the flow duct is a bypass duct of the turbomachine, and the low-temperature grid is in fluid communication with the bypass duct. In an advantageous development of the turbomachine, it further comprises a main flow duct, wherein the high-temperature grid is in fluid communication with an outlet of the main flow duct. This configuration can advantageously support water recovery from the exhaust gas of the turbomachine in a simple manner.

[0027] Further advantages and features emerge from the following description of some preferred embodiments and the dependent claims.

[0028] The invention is explained in more detail with reference to the following drawings using some preferred embodiments of the invention.

[0029] Fig. 1 shows an embodiment of a heat exchanger arrangement according to the principle of the prior art

[0030] Fig. 2a shows a first embodiment of a heat exchanger arrangement according to the invention in a sectional view of a circumferential plane of a turbomachine

[0031] Fig. 2b shows the first embodiment in a meridian section of the turbomachine

[0032] Fig. 3 shows an embodiment of a heat exchanger according to the invention in a detailed view A from Fig. 2a

[0033] Fig. 4 shows a second embodiment of a heat exchanger arrangement according to the invention in a sectional view of a circumferential plane of a turbomachine

[0034] Fig. 5 shows a third embodiment of a heat exchanger arrangement according to the invention in a sectional view of a circumferential plane of a turbomachine

[0035] Fig. 1 shows a sectional view of a prior art heat exchanger arrangement 1 comprising a heat exchanger 10 with a low-temperature grille 20 and a high-temperature grille 30. The heat exchanger 10 is arranged in a flow channel 3 between an inlet surface 2 and an outlet surface 4 of the flow channel 3. The heat exchanger has low-temperature channels in the low-temperature grille 20, which are formed substantially parallel to the main channel direction, resulting in a very large inflow area. The high-temperature channels extend into the sectional plane. The large inflow area, formed perpendicular to the flow direction, also causes high air resistance, in particular pressure and form resistance. Such configurations are disadvantageously often too large to be effectively arranged in a real engine, especially when very large cooling air flows are required.

[0036] The following are descriptions of the exemplary embodiments of the invention. For the sake of simplicity, the same reference numerals are used in the description of the exemplary embodiments of the invention as in the description of the prior art, since the component designations are the same.

[0037] Fig. 2a shows the sectional view of a heat exchanger arrangement 1 according to the invention with a flow channel 3 and a heat exchanger 10 according to the invention in the flow channel 3. The flow channel 3 is arranged in a turbomachine 100. A cooling fluid flows through the flow channel 3, wherein the cooling fluid flows into the flow channel 3 through an inlet surface 2, flows through the heat exchanger 10 and, after further flowing through the rear flow channel 3, exits the flow channel 3 again at an outlet surface 4. A main channel direction 5 is indicated by an arrow. Viewed spatially, the flow channel 3 can, for example, have the shape of a circular ring section or a rectangular shape, wherein the flow channel can be delimited laterally by channel sides.The arrangement of the flow channel 3 can be repeated, in which case some common sides can also be removed or omitted, so that a heat exchanger arrangement 1 with several heat exchangers 10 is obtained.

[0038] For example, such a heat exchanger arrangement can extend circumferentially around the core of an engine.

[0039] The heat exchanger 10 is formed from an inlet casing 13, a grid matrix consisting of a low-temperature grid 20 and a high-temperature grid 30, as well as an outlet casing 18. The grid matrix is ​​also referred to below as a heat exchanger module 11. The low- and high-temperature grids 20, 30, described in more detail in Fig. 3, are arranged in a cross-flow configuration, i.e., a plurality of low-temperature channels 21 of the low-temperature grid 20 and a plurality of high-temperature channels 31 run perpendicular to one another. The low-temperature channels 21 run largely in the direction of the indicated extension axis 27, while the high-temperature channels 31 run in a direction into the plane of the drawing. Fig. 2b shows a side view of the heat exchanger arrangement 1 from Fig. 2a, in which the direction 37 of the high-temperature channels 31 is schematically shown with larger arrows.The outlet cover 18 directs the flow of the cooling fluid in a wake downstream of the heat exchanger module 11.

[0040] The heat exchanger 10 generally has an inflow surface 14 which is inclined at an angle αi to the main channel direction 4. A more precise definition of the inflow surface is described with reference to Fig. 3. Furthermore, the heat exchanger 10 has an outflow surface 16 which is inclined at an angle α2 to the further main channel direction 4. This inclination advantageously results in a large inflow surface. Within the heat exchanger 10, the low-temperature channels 21 in turn have a main inclination angle β to the inflow surface 14 which is different from the angle αi. This minimizes the overall deflection of the cooling air as it flows through the heat exchanger, so that pressure losses are reduced.

[0041] The fluid flowing through the flow channel 3 is neither decelerated nor accelerated in the region of the inlet cladding because - as can be seen from Figs. 2a and 2b together - the cross-sectional area normal to an axial direction Ax remains constant in this region. Although the flow channel 3 narrows in an axial direction Ax in Fig. 2a, since the inlet cladding 13 already protrudes into the flow channel 3, the flow channel 3 widens in a radial direction R, as can be seen from Fig. 2b, which together leads to essentially constant areas of the cross-sections normal to the axial direction Ax through the heat exchanger arrangement 1. While the radial boundary walls can be used to reduce the cross-section to create a nozzle flow.

[0042] Fig. 2b shows the first embodiment of the heat exchanger assembly 1 from Fig. 2a in a lateral sectional view, particularly in a meridional section. The aforementioned flow direction 37 of the high-temperature grid 30 is shown. In a rear region of the heat exchanger, transverse ribs 19 are indicated in the low-temperature grid 20 and the high-temperature grid 30. These ribs represent a measure for providing an enlarged surface area for heat exchange.

[0043] In Fig. 3, the detailed view A shown in Fig. 2a is shown enlarged, wherein the actual courses of the grid matrix of the heat exchanger 10 can be seen. The heat exchanger 1 comprises the low-temperature grid 20, which consists of a plurality of low-temperature channels 21, and the high-temperature grid 30, which consists of a plurality of high-temperature channels 31. The low-temperature channels 21 each have an inlet 22, which serves to introduce and initially deflect the flow of the cooling fluid from the flow channel 3. In the present exemplary embodiment, the inlet 22 ends at a downstream constriction, which serves as an inlet cross-section 23 into a downstream diffuser region 24 of the low-temperature channel 21. The size of a cross-sectional area in the diffuser region 24 increases continuously along the longitudinal extent of the diffuser region 24 up to a maximum cross-sectional area 25 in the present exemplary embodiment.Adjacent to the diffuser region 24 downstream is a main region 26 whose cross-section is constant along its longitudinal extent. Thus, the maximum cross-sectional area of ​​a constant cross-sectional area 25 is in the main region 26. Adjacent to the main region 26 downstream is a nozzle region 28 whose cross-sectional area decreases from the size of the constant cross-sectional area 25 to an outlet cross-sectional area 29, so that the flow of the cooling fluid is accelerated. The velocity of the cooling fluid flow increases along the flow through the low-temperature channel 21 due to the heat flow from the high-temperature channel 31, through which a hot fluid flows that has a higher temperature than the cooling fluid. This further accelerates the flow in the low-temperature channel 21.

[0044] A low-temperature channel 21 and a first high-temperature channel 31 each have a first common wall 40. A high-temperature channel 31 is surrounded by a common wall, while a low-temperature channel 21 shares a common first wall 40 with a first adjacent high-temperature channel 31 and a further second common wall 40 with a second adjacent high-temperature channel 31.

[0045] The course of the first and second walls 40 in the sectional plane shown in Fig. 3 is described below initially with reference to the first wall 40: Starting at the inflow surface 14, the wall 40 has a downwind inlet section 42 in the inlet region 22. At the downwind inlet section 42, the common wall 40 has a convex diffuser section 42 in the diffuser region 24. Adjacent to the diffuser section 44, a first planar main section 46 is arranged in the main region 26. Its migration extension is used to determine the main inclination angle β. The parallelism of the migration extension in the main section 46 and the main extension 27 of the main region 26 of the low-temperature duct 21 is represented in Fig. 3 by parallel symbols. Adjacent to the main section 46 of the common wall is a concave outlet section 48 which extends to the outflow surface 16.Opposite the first common wall section, a further common wall section is arranged in the low-temperature duct 21, which has the following course: Starting at the inflow surface 14, the second common wall 40 has a windward inlet section 43 in the inlet region 22, wherein the windward inlet section 43 is rounded and wherein the rounding can extend to the point of the smallest cross-section. The windward inlet section 43 is adjoined by a concave diffuser section 45 in the diffuser section 24. The curvature of the convex diffuser section 44 of the first common wall 40 is greater than the curvature of the concave diffuser section 45 of the second common wall 40, so that the diffuser region 24 widens and thus has a continuously increasing cross-sectional area along its longitudinal extent, whereby the flow is advantageously slowed down.Adjoining the concave diffuser section 45 is a second planar main section 47 in the main region 26, which, in the sectional view, runs parallel to the extension of the first main section 46. Adjoining the second main section 47 is a convex outlet section 49 in the outlet region 28, which extends as far as the outflow surface 16. In the exemplary embodiment, a high-temperature channel 31 is surrounded by a single common wall 40 formed as a sheet metal, wherein the concave outlet section 48 and the convex outlet section 49 of the single common wall 40 abut one another and are welded or soldered, thus completely enclosing the high-temperature channel 31.

[0046] Fig. 4 shows a second embodiment of a heat exchanger arrangement 1, wherein the circumferential extent of the flow channel 3, here corresponding to the circumferential extent of the inlet surface 2, is larger than in the first embodiment, while the size of the heat exchanger 10 is identical to the size in the first embodiment. As a result, the flow is split, with a portion of the flow flowing into the heat exchanger 10 and a portion being guided past the heat exchanger 10 as a cold flow. Accordingly, a hot flow channel 6 is formed behind the outflow surface of the heat exchanger and a cold flow channel 7 next to the heat exchanger, whose outlet surfaces contribute proportionally to a total mass flow.

[0047] Fig. 5 shows a third exemplary embodiment of a heat exchanger arrangement 1, which in the exemplary embodiment represents a reflection of the heat exchanger arrangement 1 on a mirror surface 9 spanned by a radial direction R and an axial direction Ax. This creates a V-arrangement of the heat exchanger arrangement 1, wherein the heat exchanger arrangement 1 has a first heat exchanger module 11 and a second heat exchanger module 12. The two heat exchanger modules 11, 12 are connected at the front in the flow direction by a common inlet panel 13, but each have their own outlet panel 18. The inflow and outflow angles of the inflow and outflow surfaces 14, 16 can, however, vary depending on the installation situation. For example, it can be provided that a first inflow angle en of a first inflow surface 14 is smaller or larger than an inflow angle θ2 of a second inflow surface 15.The same applies to the first outflow angle ai' of the first outflow surface 16 and the first outflow angle 02' of the second outflow surface 17. The hot flow channel 6 originates at the two outflow surfaces 16 and.

[0048] 17 of the two heat exchanger modules 11, 12 and runs between them. The heated cooling gas expands between the outflow claddings 18. The cold flow channel 7 is a channel section that runs past the heat exchanger 10 on both sides.

[0049] The heat exchanger arrangement 1 described in Fig. 4 and Fig. 5 can also be arranged in a repeating pattern, so that in particular a heat exchanger arrangement 1 with several alternating hot flow channels 6 and cold flow channels 7 results.

[0050] List of reference symbols

[0051] 1 heat exchanger arrangement

[0052] 2 Entrance area on the entrance panel

[0053] 3 flow channel

[0054] 4 Exit surface on the exit panel

[0055] 5 Main channel direction

[0056] 6 Hot flow channel

[0057] 7 Cold flow channel

[0058] 10 heat exchangers

[0059] 11 first heat exchanger module

[0060] 12 second heat exchanger module

[0061] 13 Entrance panel

[0062] 14 first inflow surface

[0063] 15 second inflow surface

[0064] 16 first outflow surface

[0065] 17 second outflow surface

[0066] 18 Exit panel

[0067] 19 transverse ribs

[0068] 20 low-temperature grids

[0069] 21 Low-temperature channel

[0070] 22 Inlet

[0071] 23 Inlet cross-section

[0072] 24 Diffuser area

[0073] 25 constant cross-sectional area

[0074] 26 Main section of a low-temperature duct

[0075] 28 Nozzle area

[0076] 29 Exit cross-section

[0077] 30 high-temperature grids

[0078] 31 High-temperature channel 40 Common wall for heat transfer

[0079] 42 leeward inlet section

[0080] 43 windward inlet section

[0081] 44 convex diffuser section of the common wall

[0082] 45 concave diffuser section of the common wall

[0083] 46 straight main section of the common wall

[0084] 47 second main section of the common wall

[0085] 48 concave nozzle section of the common wall

[0086] 49 concave nozzle section of the common wall

[0087] 100 Turbomachine ai first angle of attack

[0088] 02 second angle of attack ai' first angle of attack

[0089] 02' second outflow angle ß main inclination angle

Claims

Patent claims 1. Heat exchanger (10) for cooling a hot fluid, in particular an exhaust gas or a fuel cell cooling fluid, by means of a cooling fluid having a lower temperature and a high flow velocity relative to the hot fluid, comprising a high-temperature grid (30) for guiding the hot fluid, a low-temperature grid (20) for guiding the cooling fluid, and characterized in that a diffuser region (24) for decelerating the cooling fluid is arranged in at least one first low-temperature channel (21) of the low-temperature grid (20) through which the cooling fluid flows, and that the diffuser region (24) and a first high-temperature channel (31) of the high-temperature grid (30) through which the hot fluid flows have at least one common wall (40) for heat transfer.

2. Heat exchanger according to claim 1, characterized in that the at least one common wall (40) for forming the diffuser area (24) in the first low-temperature channel (21) has a first flat or convexly curved diffuser section (42).

3. Heat exchanger according to claim 1 or 2, characterized in that the low-temperature channel (21) has a deflection area which is arranged upstream of the diffuser area (24) and in which the cooling fluid is deflected but not yet slowed down, in particular accelerated.

4. Heat exchanger according to one of the preceding claims, characterized in that a second common wall (40) is arranged in the low-temperature channel (21) opposite the first common wall (40), which on the wall side facing away from the first low-temperature channel (21) is connected to a second high-temperature channel (31) of the high-temperature grid (30) in the diffuser area (24) adjoins, wherein the second common wall (40) in the diffuser area (24) has a planar or concavely curved diffuser section (43).

5. Heat exchanger according to one of the preceding claims, characterized in that an inlet (22) for deflecting the cooling fluid into the diffuser area (24) is arranged in the flow direction of the cooling fluid upstream of the diffuser area (24).

6. Heat exchanger according to one of the preceding claims, characterized in that downstream of the diffuser region (24) an outlet region (28) with an outlet nozzle (29) for accelerating the cooling fluid is arranged.

7. Heat exchanger arrangement (1) with a heat exchanger (10), in particular with a heat exchanger (10) according to one of the preceding claims, comprising a flow channel (3) for the flow of the cooling fluid to the heat exchanger (10), wherein the heat exchanger (10) is arranged in the flow channel (3) for guiding the cooling fluid, and wherein the low-temperature grid (20) and the high-temperature grid (30) form a first heat exchanger module (11) of the heat exchanger (10), characterized in that a plurality of common walls (40) together form a first inflow surface (14) in the flow channel (3) which delimits the first heat exchanger module (11) and is spanned by the common walls (40), wherein the inflow surface (14) has an inflow angle (a) between 0° and 45°, advantageously between 3° and 15°, to a main channel direction (5) of the flow channel (3).

8. Heat exchanger arrangement according to claim 7, characterized in that a main area (26) of the low-temperature channel (21) with an extension axis (27) adjoins the diffuser area (24) downstream, in particular directly, and wherein the direction of the extension axis (27), in particular a direction of a migration extension of the common wall (40) in the main area (26), to the inflow surface (14) of the heat exchanger (10) The main inclination angle (β) is between 0° and 60°, preferably between 30° and 55°.

9. Heat exchanger arrangement according to claim 7 or 8, characterized in that a plurality of common walls (40) together form a first downstream outflow surface (16) in the flow channel (3) which limits the first heat exchanger module (11) and is spanned by the common walls (40), wherein the first outflow surface (16) forms a first outflow angle (ai') between 0° and 45°, advantageously between 3° and 15°, to a main channel direction (5) in the flow channel (3).

10. Heat exchanger arrangement according to one of claims 7 to 9, characterized in that the heat exchanger (10) is formed from the first heat exchanger module (11) and a further second heat exchanger module (12), wherein a further plurality of low-temperature channels (21) and high-temperature channels (31) form the second heat exchanger module (12) and that a further plurality of common walls (40) together form a second inflow surface (15) in the flow channel (3) which delimits the second heat exchanger module (12) and is spanned by the common walls (40), wherein the second inflow surface (15) forms a second inflow angle (02) between 0° and -45°, advantageously between -3° and -15°, to a main channel direction (5) of the flow channel (3).

11. Heat exchanger arrangement according to claim 10, characterized in that the further plurality of common walls (40) together form a second outflow surface (17) limiting the second heat exchanger module (12) upstream in the flow channel (3), wherein the second outflow surface (17) forms a second outflow angle (02') between 0° and 45°, advantageously between -3° and -15°, to a main channel direction (5) of the flow channel (3).

12. Heat exchanger arrangement according to claim 10 or 11, characterized in that the first heat exchanger module (11 ) and the second heat exchanger module (12) are symmetrical in area with respect to a common mirror surface located between the first and second heat exchanger modules (11 , 12). are formed which run parallel to a main channel direction (5) of the flow channel (3).

13. Heat exchanger arrangement according to one of claims 7 to 12, characterized in that a part of the flow channel (3) has a connection to the The cold channel (7) running past the heat exchanger (10) is formed.

14. Turbomachine (100) comprising a bypass channel and a heat exchanger arrangement according to any one of claims 7 to 13, characterized in that the flow channel (3) is a bypass channel and the low-temperature grid (20) is in fluid communication with the bypass channel and / or the high-temperature grid (30) is in fluid communication with the main flow channel.

15. Turbomachine (100) according to claim 14, characterized by several Heat exchanger arrangements according to one of claims 7 to 13, which are arranged distributed in the circumferential direction in the bypass channel.

Images