Crossflow heat exchanger, turbomachine and heat exchanger manufacturing process

Abstract

Crossflow heat exchanger, turbomachine and method of manufacturing the exchanger Crossflow heat exchanger (100) for aeronautical turbomachine configured to exchange heat between a first fluid and a second fluid, comprising: two or more sub-circuits (10) forming a first circuit configured to receive the first fluid (1), said sub-circuits (10) each extending mainly between a respective inlet (10A) and outlet (10E) in a first direction (X), said sub-circuits (10) being fluidically independent; the inlets (10A) and outlets (10E) of said sub-circuits (10) being positioned on a first face (F1) of the exchanger; said sub-circuits (10) being delimited by walls (12,14) configured to effect a heat exchange between the first fluid (1) inside said sub-circuits (10) and the second fluid (2) outside said sub-circuits (10). Figure for the abbreviation: Fig. 2A.

Description

Title of the invention: Cross-flow heat exchanger, turbomachine and method of manufacturing the exchanger Technical field

[0001] The present disclosure relates to cross-flow heat exchangers, in particular a multi-pass cross-flow heat exchanger. Prior art

[0002] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies both to new types of aircraft and to those already in circulation, requiring the implementation of technological solutions to make them compliant with current regulations. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change.

[0003] Technological research efforts have already made it possible to significantly improve the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products whose integration and use in civil aviation have moderate environmental consequences with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses on new generations of aircraft engines, the lightening of aircraft, particularly through the materials used and lighter on-board equipment.

[0006] To this end, the invention is the result of technological research aimed at very significantly improving the performance of aircraft and, in this sense, contributes to reducing the environmental impact of aircraft. For this purpose, the invention relates to a multi-pass cross-flow heat exchanger, in which the fluid circulation circuits comprise sinuosities making it possible to increase the passage time of the fluid within the exchanger, and thus to increase the efficiency heat exchanger.

[0007] The increase in the thermal efficiency of the exchanger by these sinuosities can however be done at the expense of increased pressure losses.

[0008] There is then a need for a heat exchanger offering a better compromise between thermal efficiency and pressure losses. Statement of the invention

[0009] The present disclosure aims to remedy at least in part these drawbacks.

[0010] To this end, the present disclosure relates to a cross-flow heat exchanger for an aeronautical turbomachine, configured to exchange heat between a first fluid and a second fluid, comprising: two or more sub-circuits forming a first circuit configured to receive the first fluid, said sub-circuits each extending mainly between a respective inlet and outlet in a first direction, said sub-circuits being fluidically independent; the inputs and outputs of said sub-circuits being positioned on a first face of the exchanger; said sub-circuits being delimited by walls configured to carry out a heat exchange between the first fluid inside said sub-circuits and the second fluid outside said sub-circuits.

[0011] Hereinafter, and unless otherwise indicated, by "one" or "1'" element (for example branch, sub-circuit, etc.), we mean "at least one" or "the at least one" or even "each" element. Conversely, the generic use of the plural can include the singular. Hereinafter, and unless otherwise indicated, by "a plurality" we mean "at least two".

[0012] By "direction" (in English, "direction") we mean an unoriented axis, and the term "direction" (in English, "orientation") we mean an orientation along an oriented axis.

[0013] Typically, the first direction is the general direction of flow of the first fluid in the sub-circuit of the first circuit.

[0014] The terms "inlet" and "outlet" are used in relation to the direction of circulation of the fluid; it is understood that a conduit or a collector "extends" in one direction when it allows the circulation of gas in this direction, independently of the shape of the section and the dimensions in other directions.

[0015] By fluidly independent, it is meant that the sub-circuits do not communicate fluidically with each other, that is to say that in a normal operating mode a fluid entering through the inlet of a sub-circuit can only exit through the outlet of said sub-circuit.

[0016] Such an exchanger is devoid of a common collection area or a col box reader of the first fluid inside the exchanger, typically designed to collect the fluid flowing in a given direction and direction in order to redirect it, causing significant edge effects and pressure losses.

[0017] Such an exchanger thus has a reduced volume, a reduction in the risks of poor fluid distribution and a reduction in pressure losses.

[0018] Such an exchanger thus presents, for given dimensions and operating conditions, improved thermal performance.

[0019] Furthermore, this structure is particularly suitable for additive manufacturing, for example by selective powder bed fusion.

[0020] Typically, the walls extend in a plane comprising the first direction and a second direction perpendicular to the first direction so as to obstruct movement of the second fluid in a third direction perpendicular to the first direction and the second direction.

[0021] Typically, the second direction is the general direction of flow of the second fluid within the exchanger.

[0022] Typically, the walls allow the second fluid to be directed in the second direction.

[0023] Typically, the walls comprise first fins on the side of the first circuit, preferably extending in the first direction.

[0024] The first fins contribute to directing the first fluid in the first direction. The first fins contribute to improving the efficiency of the heat exchanges between the first fluid and the exchange walls, and thus between the first fluid and the second fluid, while reducing the pressure losses.

[0025] Typically, the exchanger comprises channels of a second circuit configured to receive the second fluid, said sub-circuits being separated by all or part of the channels.

[0026] Typically, said sub-circuits are successively arranged in the second direction.

[0027] Typically, the walls comprise second fins (secondary exchange surfaces) on the side of the second circuit, preferably extending in the second flow direction.

[0028] The second fins contribute to directing the second fluid in the second flow direction. The second fins contribute to improving the efficiency of the heat exchanges between the second fluid and the exchange walls, and thus between the first fluid and the second fluid, while reducing the pressure losses.

[0029] More generally, the use of fins makes it possible to increase the exchange surface and thus improve the performance of the exchanger. The fins also allow better control of the fluid flows near the walls, and thus to further improve fluid distribution. The fins also improve the thermomechanical resistance of the exchanger in the case of high-pressure fluid flows.

[0030] Typically, when viewed in cross-section, each sub-circuit includes a generally U-shaped conduit extending between the inlet and outlet of the sub-circuit.

[0031] Typically, the generally U-shaped conduit comprises an inlet branch extending from the inlet and an outlet branch opening onto the outlet.

[0032] Typically, channels of the second circuit are formed between the input and the output of the same sub-circuit, typically between the input branch and the output branch of the same sub-circuit.

[0033] Typically, channels of the second circuit are formed between the input and the output of adjacent sub-circuits, typically between the input branch and the output branch of two adjacent sub-circuits.

[0034] The U-shape has an elbow making it possible to reduce pressure losses, in particular compared to exchangers having a collector common to the inlet branches and the outlet branches.

[0035] Typically, the inputs and outputs of adjacent subcircuits are arranged alternately. Typically, the input branches and output branches of adjacent subcircuits are arranged alternately.

[0036] This alternative arrangement allows the second fluid to always be in contact with a part of the sub-circuit towards the inlet, that is to say to always be in contact with the first fluid in its coldest state if the first fluid is a refrigerant fluid, or in its hottest state if the first fluid is a fluid to be heated.

[0037] Typically, the inputs of consecutive sub-circuits are arranged consecutively and the outputs of consecutive sub-circuits are arranged consecutively. Typically, the input branches of consecutive sub-circuits are arranged consecutively and the output branches of consecutive sub-circuits are arranged consecutively.

[0038] This consecutive arrangement makes it possible to facilitate the distribution of the first fluid to the inlets and the collection of the first fluid from the outlets of the first fluid.

[0039] Typically, the sub-circuits extend in the first direction of the exchanger over a distance greater than 90% of the length of the exchanger in the first direction, typically greater than 95%.

[0040] Typically, the sub-circuits include mechanical reinforcements opposite the first face.

[0041] Typically, mechanical reinforcements include support arches.

[0042] The arches provide mechanical reinforcement without significantly disrupting the circulation of the first fluid.

[0043] Typically, the exchanger comprises a collector configured to divide an incoming flow and an outgoing flow from and to the sub-circuits.

[0044] Typically, the exchanger comprises a collector configured to divide an incoming flow and an outgoing flow from and to adjacent sub-circuits.

[0045] Typically, the collector comprises walls having an angle of less than 45° with the first direction.

[0046] Such an angle makes it possible to limit the deflection of the second gas flow at the inlet and outlet of the walls, and to reduce pressure losses compared to known solutions having angles close to 90°.

[0047] The invention also relates to an aeronautical turbomachine comprising a heat exchanger according to the invention.

[0048] Typically, the first circuit is connected to at least one of a turbomachine compressor and a combustion chamber, for example an area located between a compressor outlet and a combustion chamber inlet, and the second circuit is connected on the one hand to a turbine, typically downstream, and on the other hand to an exhaust nozzle.

[0049] Typically, the first circuit is connected to a lubrication circuit and the second circuit is connected to a secondary air stream or a third stream, and an exhaust nozzle.

[0050] The invention also relates to a method of manufacturing a heat exchanger for an aeronautical turbomachine according to the invention comprising at least one step of additive manufacturing on a powder bed. Brief description of the drawings

[0051] Other characteristics and advantages of the subject of the present disclosure will emerge from the following description of embodiments, given as non-limiting examples, with reference to the appended figures.

[0052] [Fig-1] [Fig. 1] is a cutaway perspective view of a cross-flow heat exchanger.

[0053] [Fig.2A] [Fig.2A] is a schematic view along section plane II-II of [Fig.1].

[0054] [Fig.2B] [Fig.2B] is a schematic view corresponding to the view of [Fig.2A] where the direction of circulation of the first fluid is modified.

[0055] [Fig.3] [Fig.3] is an enlargement of part III of [Fig.2A].

[0056] [Fig.4] [Fig.4] is an enlarged perspective view of Part IV of [Fig.l].

[0057] [Fig.5] [Fig.5] is a perspective view of an example of inlet and outlet ducts exit.

[0058] [Fig.6] [Fig.6] is a schematic representation of the integration of the exchanger cross-flow in a turbomachine. Description of the embodiments

[0059] [Fig.l] represents a cutaway view of a cross-flow heat exchanger 100, hereinafter referred to as “exchanger”.

[0060] In the cutaway view of [Fig. 1], certain sub-circuits 10 are not shown for the purpose of visualizing the internal structure of the exchanger 100. Furthermore, for the purpose of illustration, the collector 19 is not shown and will be described below in relation to [Fig. 5].

[0061] The exchanger 100 is provided for exchanging heat (heat exchange) between a first fluid 1 circulating substantially in a first flow direction X and a second fluid 2 circulating substantially in a second flow direction Y.

[0062] By flow direction is meant an overall direction of flow of the fluid considered, independently of any local disturbances likely to affect the flow direction.

[0063] The local direction of circulation of the first fluid 1 is represented schematically by an arrow without filling. The local direction of circulation of the second fluid 2 is represented schematically by an arrow with full filling. For reasons of readability of the figures, certain numerical references including the numerical references of these arrows are not systematically represented.

[0064] As shown in [Fig.6], the exchanger 100 can receive the first fluid 1 from an element 101, and redirect it to the element 101 after passing through the exchanger 100.

[0065] The exchanger 100 can receive the second fluid 2 from an element 102, and redirect it to an element 103.

[0066] The elements 101, 102, 103 and the exchanger 100 can be integrated into a turbomachine 200.

[0067] The first fluid 1 and the second fluid 2 may be two gases, for example the exchanger 100 receiving and redirecting the respective fluids from or to a turbomachine compressor 101, typically downstream, a combustion chamber 101, typically upstream, or a zone 101 formed between an outlet of a compressor and a combustion chamber inlet, a turbine 102, and an exhaust nozzle 103, for example in the case where the turbomachine 100 comprises a recuperated cycle gas turbine.

[0068] For example, the first fluid 1 and the second fluid 2 may respectively comprise a gas and a liquid, in particular oil, for example the exchanger 100 receiving and redirecting the respective fluids from or to a lubrication circuit 101, a secondary air stream 102 or a third stream 102, an exhaust nozzle 103.

[0069] The exchanger 100 comprises two or more sub-circuits 10 forming a first circuit receiving the first fluid 1.

[0070] Subcircuit 10 will be described in more detail with respect to Figures 1, 2A, 2B and 3.

[0071] The sub-circuit 10 extends on the one hand along the first direction X. The sub-circuit 10 further extends along the second direction Y. The sub-circuit 10 is substantially translationally invariant along the second direction Y, so that the structure of the sub-circuit 10 described below extends along the second direction Y.

[0072] Along the path of the first fluid 1, the sub-circuit 10 extends between an inlet 10A and an outlet 10E.

[0073] The inputs 10A and outputs 10E of the sub-circuits 10 are typically provided on the same face of the exchanger, for example designated by “first face” F1 illustrated in [Fig.l].

[0074] As shown in the view of Figures 2A and 3, between the inlet 10A and the outlet 10E, the circuit may comprise a conduit in the general shape of a U seen in a plane perpendicular to the second direction Y.

[0075] In particular, along the path of the first fluid 1, the sub-circuit 10 may comprise, in this order, between the inlet 10A and the outlet 10E: an inlet branch 10B, a half-turn 10C (“U-turn” or 180° flow deviation) and an outlet branch 10D.

[0076] Seen in a plane perpendicular to the second direction Y (figures 2A and 3), that is to say a plane comprising the first direction X and a third direction Z perpendicular to the first direction X and to the second direction Y, the half-turn 10C takes the form of a 180° elbow redirecting the fluid from the inlet branch 10B to the outlet branch 10D with a common direction and an opposite direction.

[0077] The input branch 10B and the output branch 10D are each delimited by an inner wall 12 and an outer wall 14.

[0078] Here we designate interior and exterior with respect to the assembly formed by the sub-circuit 10.

[0079] Typically, the inlet branch 10B and the outlet branch 10D surround a common channel 22 of a second circuit, configured to receive the second fluid 2.

[0080] The inner 12 and outer 14 walls thus contribute to the heat exchanges between the first fluid 1 and the second fluid 2. The inner 12 and outer 14 walls are thus typically exchange walls.

[0081] Within the meaning of the previous definition, the channel 22 framed by an input branch 10B and an output branch 10D of the same sub-circuit 10 is thus considered to be internal to the sub-circuit 10.

[0082] The input branch 10B and the output branch 10D are each delimited by an inner wall 12. The inner walls 12 which delimit the input branch 10B and the output branch 10D of the same sub-circuit 10 typically delimit the so-called inner channel 22.

[0083] A channel 22 may also be formed between two consecutive sub-circuits 10, that is to say two sub-circuits 10 consecutively arranged in a third direction Z, for example between adjacent outer walls 14 of branches 10B, 10D of two consecutive sub-circuits 10.

[0084] Such a channel 22 formed between two consecutive sub-circuits 10 is thus considered to be external.

[0085] The inner 12 and outer 14 walls typically extend in a plane formed by the first direction X and the second direction Y. Thus, the channels 22 typically extend between the first direction X and the second direction Y, thus allowing the circulation of the second fluid 2 in the second direction Y.

[0086] As shown in [Fig.l], the direction of circulation of the first fluid 1 in the sub-circuits 10 can be the same for all the sub-circuits 10. In other words, the inlets 10A and the outlets 10E of the sub-circuits 10 can be arranged alternately, that is to say alternately in the third direction Z. In other words, in the third direction Z, the inlets 10A and the outlets 10E are arranged in an “inlet - outlet - inlet - outlet” pattern.

[0087] For example, from left to right in [Fig.l] along the third direction Z, there are arranged consecutively and in this order an output 10E, an input 10A of a first sub-circuit 10 then an output 10E and an input 10E of a second sub-circuit 10 adjacent to the first sub-circuit 10.

[0088] In such an alternative arrangement between inputs 10A and outputs 10E illustrated in [Fig.2A], a channel 22 is then formed between the outer walls 14 of respective input branches 10B of two alternative sub-circuits 10, or between the outer walls 14 of output branches 10D.

[0089] In the view of [Fig.2B], the directions of circulation of the first fluid 1 have been altered compared to the view of [Fig.2A], corresponding to an alternative embodiment.

[0090] As shown in [Fig.2B], the direction of circulation of the first fluid 1 in the sub-circuits 10 can be reversed between two consecutive sub-circuits 10. In other words, the inlets 10A and the outlets 10E of the sub-circuits 10 can be arranged consecutively, that is to say that two inlets 10A are arranged consecutively and that two outlets 10E are arranged consecutively in the third direction Z. In other words, in the third direction Z, the inlets 10A and the outlets 10E are arranged in an “inlet - outlet - outlet - inlet” pattern.

[0091] In such an alternative arrangement of the inputs 10A and outputs 10E, and thus of the input branches 10B and output 10D, a channel 22 is then formed between the outer walls 14 of an input branch 10B and an output branch 10D of two consecutive sub-circuits 10.

[0092] The sub-circuits 10 can also extend along the second direction Y. In other words, the inner walls 12 and the outer walls 14 can extend substantially in a plane comprising the first direction X and the second direction Y, so as to allow heat exchanges between the first fluid 1 and the second fluid 2.

[0093] The inner walls 12 and the outer walls 14 may comprise fins.

[0094] For example, as illustrated in detail in [Fig. 3], the inner walls 12 and the outer walls 14 may have first fins 13 and / or second fins 15.

[0095] The first fins 13 are typically provided on the side of the first circuit, so as to direct the first fluid 1 within the sub-circuit 10.

[0096] For example, the first fins 13 are provided to extend mainly in the first direction X, as well as in the third direction Z, so as to reduce a local movement of the first fluid 1 in the second direction Y, and thus to channel the first fluid 1 locally in the first direction X.

[0097] For example, the second fins 15 are provided to extend mainly in the second direction Y, as well as in the third direction Z, so as to reduce a local movement of the second fluid in the direction X, and thus to channel the second fluid 2 locally in the second direction Y.

[0098] The fins 13, 15 also contribute to the thermal exchanges between the fluids 1, 2 and the walls 12, 14 present.

[0099] The fins 13, 15 may or may not extend continuously from one wall 12, 14 to the other in the third direction Z, thus defining a honeycomb structure further reducing local fluid movements in the corresponding direction among the first direction X and the second direction Y, i.e. encouraging the circulation of the fluids 1, 2 in their general flow direction among the first direction X and the second direction Y.

[0100] The fins 13, 15 may extend over all or part of the length of the walls 12, 14 in the direction of flow of the corresponding fluid among the first fluid 1 and the second fluid 2.

[0101] The fins 13, 15 may for example be arranged on the walls 12, 14 along the entire path of the respective fluid among the first fluid 1 and the second fluid 2. Typically, the fins 13, 15 may be continuous along the entire direction of circulation of the corresponding fluid among the first fluid 1 and the second fluid 2, or even be discontinuous. Where appropriate, the discontinuous fins 13, 15 may be provided in the extension of one another in the direction of circulation of the corresponding fluid among the first fluid 1 and the second fluid 2.

[0102] The sub-circuit 10 may comprise a mechanical reinforcement 18. The reinforcement 18 typically comprises one or more support arches 18.

[0103] The reinforcement 18 is for example provided in the half-turn 10C.

[0104] An example of a support arch is shown in the enlargement of [Fig.4].

[0105] The support arch 18 has, for example, a cross-ribbed shape.

[0106] The reinforcement 18 comprises for example a plurality of support arches 18 arranged along the second Y direction, typically regularly arranged along the second Y direction.

[0107] Such a structure makes it possible to provide a mechanical reinforcement function, in particular of the internal walls 12, and is in particular compatible with manufacturing by additive methods.

[0108] The reinforcement 18 is typically provided so as to extend in the first direction X between a second face F2 opposite the first face F1 and one end of the channel 22 at a height h, shown in [Fig.l].

[0109] The height h is for example between 1.2 mm and 5 mm. The height h can for example be between 0.5xd4 and 2xd4, where d4 is a dimension (not shown) chosen from the height of a fin 13 measured along the third direction Z, the total height measured along the third direction Z of two fins 13 respectively provided on the walls 12 and 14 in the extension of one another, and the width of the inlet branch 10B or of the outlet branch 10D measured along the third direction Z.

[0110] The reinforcement 18 may for example have a length d3 along the third direction Z ([Fig.3]), and a depth pl along the second direction Y ([Fig.4]).

[0111] The length d3 and the length pl can be between 1 mm and 20 mm, for example the length d3 and the depth pl can be equal to each other.

[0112] Such a structure thus makes it possible to provide structural reinforcement of the channel 22 without significantly reducing the passage section of the first fluid 1.

[0113] Such a structure also makes it possible to provide mechanical support for the exchanger 100 during manufacturing operations using additive methods, in particular reducing the overhang of the supported sub-circuit 10.

[0114] The length (represented vertically in [Fig.l]) L of the exchanger in the first direction X is typically between 30 mm and 400 mm, for example between 100 mm and 300 mm. The length L is for example measured between the first face F1 and the second face F2 opposite the first face FL

[0115] The depth P of the exchanger in the second direction Y is typically between 50 mm and 1 m, for example between 50 mm and 500 mm, or between 100 mm and 300 mm. For example, the depth P is between 10 mm and 400 mm, for example between 20 mm and 250 mm

[0116] The width d1 of a sub-circuit 10 along the third direction Z ([Fig.2A] and 2B) is typically between 10 mm and 400 mm, for example between 20 mm and 250 mm. The width d2 of the channel 22 along the third direction Z is typically between 10 mm and 250 mm.

[0117] For the purposes of illustration, the exchanger 100 has been shown with two sub-circuits 10. It is understood, however, that the exchanger 100 may comprise more sub-circuits, 10, typically between five and fifty sub-circuits 10.

[0118] The width D along the third direction Z may be equal to the sum of the total widths of the sub-circuits 10 and the channels 22, where the number of channels 22 is one less than the number of sub-circuits 10.

[0119] For example, the width D of the exchanger in the third direction Z is typically between 50 mm and 1 m, for example between 50 mm and 500 mm, or between 100 mm and 300 mm. For example, the width D is between 10 mm and 400 mm, for example between 20 mm and 250 mm.

[0120] The exchanger 100 may comprise a collector 19 provided to divide an incoming flow and an outgoing flow of the first fluid 1 from and to the different sub-circuits 10.

[0121] A collector 19 is shown in [Fig. 5]. The collector 19 is typically provided adjacent to the first face F1, that is to say fluidically in the extension of the sub-circuit 10, in particular in the extension of the inlet 10A and the outlet 10E of the sub-circuit 10, in other words in the extension of the inlet branch 10B and the outlet branch 10D of the sub-circuit 10.

[0122] The collector 19 comprises, for example, walls 19A, inclined in a plane formed by the first direction X and the second direction Y, configured to direct in the second direction Y an incoming flow and / or an outgoing flow of the sub-circuit 10.

[0123] The collector 19 comprises, for example, walls 19B, inclined in a plane formed by the first direction X and the third direction Z, configured to direct in the third direction Z an incoming flow and / or an outgoing flow of the sub-circuit 10.

[0124] The inclination of the walls 19A, 19B is the angle formed between the direction normal to the walls 19A, 19B and the first direction X.

[0125] The walls 19A, 19B may for example have an inclination of less than 45°, for example between 10° and 45°.

[0126] The exchanger 100 has a structure which is particularly suitable for production by an additive manufacturing process. A manufacturing process for the exchanger 100 can then be implemented, entirely or partially, by additive manufacturing, for example by a powder bed laser fusion process.

[0127] Although the present invention has been described with reference to specific exemplary embodiments, it is obvious that modifications and changes may be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various illustrated / mentioned embodiments may be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

Claims

Claims

1. Cross-flow heat exchanger (100) for an aeronautical turbomachine, configured to exchange heat between a first fluid and a second fluid, comprising: two or more sub-circuits (10) forming a first circuit configured to receive the first fluid (1), said sub-circuits (10) each extending mainly between a respective inlet (10A) and outlet (10E) in a first direction (X), said sub-circuits (10) being fluidically independent; the inlets (10A) and outlets (10E) of said sub-circuits (10) being positioned on a first face (F1) of the exchanger; said sub-circuits (10) being delimited by walls (12, 14) configured to carry out a heat exchange between the first fluid (1) inside said sub-circuits (10) and the second fluid (2) outside said sub-circuits (10).

2. Cross-flow heat exchanger (100) for an aeronautical turbomachine according to claim 1, in which the walls (12, 14) extend in a plane comprising the first direction (X) and a second direction (Y) perpendicular to the first direction (X) so as to obstruct a movement of the second fluid in a third direction (Z) perpendicular to the first direction (X) and to the second direction (Y).

3. Cross-flow heat exchanger (100) for an aeronautical turbomachine according to claim 1 or 2, in which the walls (12, 14) comprise, on the side of the first circuit, first fins (13), preferably extending in the first direction (X).

4. Cross-flow heat exchanger (100) for an aeronautical turbomachine according to any one of claims 1 to 3, comprising channels (22) of a second circuit configured to receive the second fluid (2), said sub-circuits (10) being separated by all or part of the channels (22).

5. Cross-flow heat exchanger (100) for an aeronautical turbomachine according to claim 4, in which the walls (12, 14) comprise second fins (15) on the side of the second circuit.

6. A cross-flow heat exchanger (100) for an aeronautical turbomachine according to any one of claims 1 to 5, wherein seen in a cross-section, each sub-circuit (10) comprises a generally U-shaped conduit extending between the input (10A) and the output (10E) of the sub-circuit (10).

7. Cross-flow heat exchanger (100) for an aeronautical turbomachine according to any one of claims 1 to 6, in which the inlets (10A) and the outlets (10E) of adjacent sub-circuits (10) are arranged alternately.

8. Cross-flow heat exchanger (100) for an aeronautical turbomachine according to any one of claims 1 to 7, in which the sub-circuits (10) extend in the first direction (X) over a distance greater than 90% of the length of the exchanger in the first direction (X).

9. Cross-flow heat exchanger (100) for an aeronautical turbomachine according to any one of claims 1 to 8, in which the sub-circuits (10) comprise mechanical reinforcements (18) opposite the first face (F1).

10. A cross-flow heat exchanger (100) for an aeronautical turbomachine according to any one of claims 1 to 9, comprising a manifold (19) configured to divide an incoming flow and an outgoing flow of the first fluid (1) from and to the sub-circuits (10).

11. An aeronautical turbomachine (200) comprising a cross-flow heat exchanger (100) for an aeronautical turbomachine according to any one of claims 1 to 10.

12. An aeronautical turbomachine (200) according to claim 11, wherein the first circuit is connected to at least one of a turbomachine compressor and a combustion chamber (101) and the second circuit is connected to a turbine (102) and an exhaust nozzle (103).

13. Method of manufacturing a cross-flow heat exchanger (100) for an aeronautical turbomachine according to any one of claims 1 to 10, comprising at least one step of additive manufacturing on a powder bed.

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