Surface heat exchanger for a nacelle of a turbine engine, and turbine engine nacelle equipped with such a heat exchanger

Abstract

The invention relates to a surface heat exchanger (20), in particular for an aircraft nacelle, comprising a first metal sheet (21) and a second metal sheet (22) that are joined together, and at least three distribution channels (25) disposed between the first metal sheet (21) and the second metal sheet (22), the exchanger also comprising an inlet hydraulic interface (28) and an outlet hydraulic interface (29). Each of the distribution channels (25) is connected directly to the inlet hydraulic interface (28) and the outlet hydraulic interface (29), and the distribution channels (25) are distributed all around the perimeter of the inlet hydraulic interface (28) and / or the outlet hydraulic interface (29).

Description

[0001] DESCRIPTION

[0002] TITLE: Surface heat exchanger for a turbomachine nacelle and turbomachine nacelle equipped with such a heat exchanger

[0003] Technical field of the invention

[0004] The present invention relates to the field of heat exchangers, in particular fairings of an aircraft engine, called "nacelle".

[0005] State of the prior art

[0006] Generally, an aircraft is powered by one or more propulsion units, each comprising an engine or turbojet housed in a tubular nacelle.

[0007] A nacelle generally comprises a tubular body comprising an upstream section comprising an air inlet upstream of the turbojet engine, a middle section configured to surround a fan of the turbojet engine and a downstream section configured to house thrust reverser means and to surround the combustion chamber of the turbojet engine. The nacelle generally comprises an ejection nozzle downstream of the downstream section and the outlet of which is located downstream of the turbojet engine.

[0008] In addition, the nacelle usually includes an external structure and an internal fixed structure, called "inner fixed structure", acronym "IFS" in English terms. The internal fixed structure is concentric with the external structure, at the downstream section and surrounds the core of the turbojet downstream of the fan.

[0009] These external and internal structures define an annular flow vein, called a secondary vein, aimed at channeling a flow of cold air, called secondary, circulating outside the turbojet.

[0010] The external structure comprises an external fairing defining an external aerodynamic surface and an internal fairing defining an internal aerodynamic surface. The internal and external fairings are connected upstream by a leading edge wall forming an air inlet lip. Generally, the turbojet engine comprises a set of blades driven in rotation by a gas generator through a set of transmission means. The nacelle further comprises a lubricant distribution system to ensure good lubrication of these transmission means and to cool them. The lubricant is advantageously oil.

[0011] To cool the lubricant, the nacelle typically includes a cooling system with at least one heat exchanger. The cooling system is configured to circulate a fluid, such as the lubricant or a coolant, to cool the lubricant.

[0012] Among heat exchangers, air / lubricant exchangers are known, which use air taken from the secondary stream (called cold flow) of the nacelle or one of the first stages of the compressor. The taking and circulation of air through the heat exchanger disrupts the flow of the air stream and causes additional pressure losses, called drag, which is not desirable.

[0013] We also know the finned heat exchangers fixed on one of the walls of the nacelle delimiting the secondary vein. The fluid is cooled by the flow of the air flow in the secondary vein which circulates along the fins on the surface of the exchanger.

[0014] Such a solution also generates significant aerodynamic losses.

[0015] This results in significant losses in fuel consumption.

[0016] Fluid cooling systems are also known that include a structural surface exchanger.

[0017] In the example illustrated in Figures 1 and 2, a structural surface exchanger 10 without fins comprising a first corrugated skin 11 and a second skin 12 called smooth, assembled by welding or brazing or riveting.

[0018] Distribution channels 13 are formed by assembling the first skin 11 having undulations on the second skin 12, said skins 11, 12 then forming the double wall of the internal and / or external fairing. Each distribution channel 13 is delimited by a corrugation of the first skin 11 and the second smooth skin 12.

[0019] A fluid, for example, a heat transfer fluid or the lubricant, is intended to circulate in the channels 13 and air is intended to circulate in contact with the second smooth skin 12.

[0020] For this purpose, the second smooth skin 12 is intended to be in contact with an air flow. It makes it possible to maximize the flow of the air flow. We speak of an aerodynamic skin.

[0021] The heat exchanger 10 further comprises a distributor 14 and a fluid collector 15.

[0022] The fluid distributor 14 is a cavity formed in the first corrugated skin 11 allowing the fluid to be distributed at the inlet of the channels 13. The fluid distributor 14 is connected to a hydraulic inlet interface 16 of the exchanger.

[0023] The fluid collector 15 is a cavity formed in the first corrugated skin 11 allowing the fluid to be distributed at the outlet of the channels 13. The fluid collector 15 is connected to a hydraulic interface 17 at the outlet of the exchanger.

[0024] The heat exchanger 10 also comprises one or more stiffeners or reinforcing members 18 welded between the first and second skins 11, 12 and configured to ensure the structural strength of said exchanger.

[0025] In this regard, reference may be made to document ER 3 094 657 which describes a manufacturing process for a structural surface exchanger for a nacelle.

[0026] However, the presence of distributor and collector generates risks of forming due to the orientation of the distribution channels perpendicular to the orientation of the distributor and collector. The forming of the radii of connection of the distribution channels to the support surface, as well as the radii of connection of the distributor and collector to the support surface are not optimized and induce high risks of tearing of the sheet metal.

[0027] Hydraulic pressure losses are also significant due to the presence of stiffeners between the distributor and the bearing surface and between the manifold and the bearing surface. Furthermore, the unsupported widths of the distributor, the manifold and the hydraulic interface points generate peeling forces incompatible with current standards in the field of lap welding.

[0028] There is a need to optimize fluid cooling systems, particularly heat exchanges between a fluid and air, while optimizing the structural strength of the heat exchanger.

[0029] Statement of the invention

[0030] The present invention therefore aims to overcome the aforementioned drawbacks.

[0031] The objective of the invention is to improve the thermal exchanges between a fluid circulating in a heat exchanger and the air circulating outside said heat exchanger, while optimizing the structural strength of the heat exchanger.

[0032] The invention relates to a turbomachine nacelle comprising an external structure and an internal structure delimiting an annular secondary flow vein, aimed at channeling a cold air flow, called secondary, circulating outside the turbomachine. Said nacelle comprises a housing for a turbomachine, which delimits with the internal structure an annular primary flow vein.

[0033] The nacelle comprises at least one surface heat exchanger fixed either to the external structure, on the side of the secondary vein or on the side external to said external structure, or to the internal structure, on the side of the secondary vein or on the side of the primary vein.

[0034] When the exchanger is fixed on the internal surface of the internal fairing, the heat exchanger is fixed in the secondary vein, so that the air flow circulating in the secondary vein is in contact with the second sheet metal.

[0035] When the exchanger is fixed on the external surface of the internal structure of the nacelle, the heat exchanger is fixed in the secondary vein, so that the air flow circulating in the secondary vein is in contact with the second sheet metal.

[0036] When the exchanger is fixed on the external surface of the external structure of the nacelle, the heat exchanger is fixed so that the external air flow is in contact with the second sheet metal.

[0037] Thus, the heat exchanger can be used to cool a fluid from the secondary flow or from the outside air.

[0038] When the heat exchanger is fixed on the internal surface of the internal structure, i.e. in the fluid flow of the primary vein, it can be used to heat a fluid from the primary flow.

[0039] The surface heat exchanger comprises a first skin or sheet and a second skin or sheet assembled together and at least three distribution channels arranged between the first sheet and the second sheet.

[0040] The exchanger further comprises an inlet hydraulic interface and an outlet hydraulic interface.

[0041] Each of the distribution channels is connected directly to the inlet hydraulic interface and the outlet hydraulic interface and the distribution channels are regularly distributed around the entire perimeter of the inlet hydraulic interface and / or the outlet hydraulic interface.

[0042] The absence of a distributor and collector improves the ease of forming the distribution channels, or even makes it possible to eliminate the operation of forming the first sheet, reduces and homogenizes hydraulic pressure losses, which improves thermal performance.

[0043] Additionally, unsupported widths are reduced, increasing the structural holding capacity of the heat exchanger.

[0044] By "directly" we mean a direct connection without an intermediate element. In other words, there is no longer a collector and distributor located between the channels and the inlet and outlet hydraulic interfaces respectively.

[0045] This allows for a larger number of channels and for a uniform distribution at the input or output regardless of the number of channels. This also limits load losses by directly supplying each channel from the input interface.

[0046] By "surface exchanger" we mean an exchanger without fins, a smooth exchanger, whose wall or skin which defines the vein forms the heat exchange surface.

[0047] The fact of not having fins, or other shapes intended to increase the contact surface between the flow and the exchanger, allows there to be no obstacle to the air flow in the vein, and therefore to reduce aerodynamic load losses.

[0048] The term "sheet metal" means a flat steel product, rolled either hot or cold, with a generally smooth surface or sometimes with projections. A sheet metal is therefore made of metallic material.

[0049] The distribution channels are configured to extend between the inlet hydraulic interface and the outlet hydraulic interface.

[0050] By "distributed around the entire perimeter of the hydraulic interface" is meant that certain channels are connected to one of the hydraulic interfaces by a first end extending in a direction opposite to the other of the hydraulic interfaces.

[0051] The ends are extended by a main part, for example rectilinear, extending towards the other of the hydraulic interfaces to a second end.

[0052] The second end may also extend in a direction opposite one of the hydraulic interfaces.

[0053] For example, the channels are connected to the inlet hydraulic interface by an inlet end and to the outlet hydraulic interface by an outlet end.

[0054] The input end is, for example, connected to the output end by a main part.

[0055] An inlet end of at least one channel extends in a direction opposite the outlet hydraulic interface and an outlet end of at least one channel extends in a direction opposite the inlet hydraulic interface.

[0056] For example, the inlet and outlet hydraulic interfaces have a circular cross-section.

[0057] For example, the inlet and outlet hydraulic interfaces each include an outlet orifice extending along a plane perpendicular to the extension planes of the sheets.

[0058] Advantageously, the thickness of each distribution channel is constant over the entire length of the corresponding channel.

[0059] For example, distribution channels have an identical cross-section between them.

[0060] Alternatively, different cross-sections could be provided between each of the channels. For example, the longer distribution channels could be provided with a larger cross-section in order to balance the flow rates between the said distribution channels.

[0061] According to one embodiment, each of the first and second sheets is flat.

[0062] Alternatively, each of the first and second sheets is curved to provide aerodynamic continuity with the rest of the nacelle.

[0063] Advantageously, the exchanger comprises a plurality of spacers or spacing members arranged between the first sheet and the second sheet, two adjacent spacing members delimiting a distribution channel.

[0064] For example, the first sheet and the second sheet are assembled together by an assembly zone, for example welding or brazing, at the level of the spacing members, said assembly zone extending from the first sheet to the second sheet.

[0065] Alternatively, the assembly zone may pass through the corresponding spacer member.

[0066] For example, the spacers each have a thickness between 2mm and 4mm, for example equal to 3mm.

[0067] Alternatively, the spacers may be part of the second sheet, by machining the inter-channel areas and the channels directly on said second sheet. In this alternative, the thickness of the assembly area is reduced and extends from the first sheet to the adjacent portion of the second sheet.

[0068] For example, the section of each of the distribution channels has the shape of a quadrilateral, such as for example a trapezoid, a square, a rectangle, etc.

[0069] According to one embodiment, the first sheet comprises a plurality of corrugations, the distribution channels each being delimited by a corrugation of the first corrugated sheet and the second sheet.

[0070] For example, each distribution channel has a semicircular section.

[0071] Generally, the first sheet has a thickness between 1 and 2mm and the second sheet has a thickness between 0.6 and 2mm.

[0072] The first sheet and / or the second sheet is made of aluminum or an alloy containing aluminum. This improves the lightness, the formability of the sheets and thermal exchanges.

[0073] Advantageously, the exchanger comprises an axis of symmetry passing through the inlet hydraulic interface and the outlet hydraulic interface, the distribution channels being arranged symmetrically with respect to said axis of symmetry.

[0074] Brief description of the drawings

[0075] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example, and made with reference to the indexed drawings in which:

[0076] [Fig 1], is a schematic view of a structural surface exchanger according to the prior art;

[0077] [Fig 2] is a partial sectional detail view of the exchanger of Figure 1;

[0078] [Fig 3] is a schematic view of a surface heat exchanger according to one embodiment of the invention;

[0079] [Fig 4] is a partial sectional detail view of the exchanger of Figure 3;

[0080] [Fig 5] is a schematic view of a surface heat exchanger according to a second embodiment of the invention;

[0081] [Fig 6] is a partial sectional detail view of the exchanger of Figure 5;

[0082] [Fig 7] is a schematic view of a surface heat exchanger according to a third embodiment of the invention;

[0083] [Fig 8] is a schematic view of a surface heat exchanger according to a fourth embodiment of the invention;

[0084] [Fig 9] is a schematic view of a surface heat exchanger according to a fifth embodiment of the invention;

[0085] [Fig 10] is a schematic view of a surface heat exchanger according to a sixth embodiment of the invention; and

[0086] [Fig 1 1] is a schematic view of a turbomachine comprising an aircraft nacelle equipped with a heat exchanger according to one of the embodiments of the invention.

[0087] Detailed description of at least one embodiment

[0088] In the remainder of the description, the terms "upstream" and "downstream" are defined in relation to the direction of air flow in the turbomachine. The terms "internal" and "external" are defined in relation to the longitudinal axis of the turbomachine, the internal term defining an element closer to said axis than an external element.

[0089] With reference to the example illustrated in Figures 3 and 4, a heat exchanger 20 comprises a first skin or sheet 21 and a second skin or sheet 22 assembled one on the other by means of spacers or spacing members 23, 24 visible in Figure 4.

[0090] The spacers 23, 24 and the second skin 22 form a single piece.

[0091] Each of the first and second skins 21, 22 is here flat. Alternatively, it could be provided that the first and second skins 21, 22 are curved.

[0092] The exchanger 20 comprises a plurality of distribution channels 25 each delimited laterally between two adjacent spacers 23, 24 and vertically between the first and second skins 21, 22. In a non-limiting manner, the section of each of the distribution channels 25 here has the shape of a rectangle. Alternatively, it could be provided that the section has the general shape of any quadrilateral, such as for example a trapezoid, a square, etc. Generally speaking, the section of each of the distribution channels 25 can be of any shape.

[0093] As illustrated, the distribution channels 25 have an identical section between them.

[0094] Alternatively, different sections could be provided between each of the channels.

[0095] For example, it could be provided that the longer distribution channels have a larger cross-section in order to balance the flow rates between said distribution channels, as can be seen in the example in Figure 8.

[0096] The distribution channels 25 are directly connected respectively to an inlet hydraulic interface 28 and to an outlet hydraulic interface 29.

[0097] In other words, there is no longer a collector and distributor located between the channels 25 and respectively the inlet 28 and outlet 29 hydraulic interfaces.

[0098] As illustrated in Figure 3, the inlet ends 25a of the distribution channels 25 are distributed uniformly, that is to say regularly distributed, over the entire periphery of the inlet hydraulic interface 28 and the outlet ends 25b of the distribution channels 25 are distributed uniformly over the entire periphery of the outlet hydraulic interface 29.

[0099] Preferably, the distribution channels 25 may be regularly distributed circumferentially between them around the inlet hydraulic interface 28 and / or the outlet hydraulic interface 29. In other words, the “center” of each distribution channel 25, at the connection with the inlet hydraulic interface 28 and / or the outlet hydraulic interface 29, is regularly circumferentially spaced from the “center” of an adjacent distribution channel.

[0100] Generally, the distribution channels 25 are distributed around the entire perimeter of the inlet hydraulic interface 28 and / or the outlet hydraulic interface 29.

[0101] By "distributed over the entire circumference" is meant that an inlet end 25a of at least one channel 25 extends in a direction opposite to the outlet hydraulic interface 29 and that an outlet end 25b of at least one channel 25 extends in a direction opposite to the inlet hydraulic interface 28.

[0102] The inlet ends 25a of the channels 25 and the outlet ends 25b of the channels 25 have a curved shape.

[0103] The concavity of the inlet ends 25a and the outlet ends 25b of the channels 25 is directed towards the center of the exchanger 20.

[0104] The inlet ends 25a and the outlet ends 25b are connected to each other by a main part 25d, here rectilinear.

[0105] The first and second skins 21, 22 are assembled by an assembly zone 26, 27, for example a welding or brazing zone 26, 27 at the spacers 23, 24. Said assembly zone 26, 27 extends from the first skin 21 to the second skin 22, passing through the corresponding spacer 23, 24.

[0106] Alternatively, the spacers may be part of the second sheet, by machining the inter-channel areas and the channels directly on said second sheet. In this alternative, the thickness of the assembly area is reduced and extends from the first sheet to the adjacent portion of the second sheet.

[0107] As illustrated in Figure 3, and by way of non-limiting example, the exchanger 20 comprises eight distribution channels 25.

[0108] Alternatively, the heat exchanger 20 could comprise a different number of distribution channels 25, for example greater than or equal to three, as illustrated in FIG. 7 or greater than or equal to four, as illustrated in the example of FIG. 9 in which the same elements bear the same references.

[0109] In the embodiments illustrated in Figures 3, 5, 7 to 9, the exchanger 20, 30 comprises an axis of symmetry S1-S1 passing through the inlet interface 28 and the outlet interface 29. The distribution channels 25, 35 are arranged symmetrically with respect to said axis of symmetry S1, S1. In the example illustrated in Figure 10, the concavity of the inlet ends 25a and the outlet ends 25b of the channels 25 is directed towards the center of the exchanger 20. The inlet ends 25a and the outlet ends 25b are connected to each other by a main part comprising a first rectilinear portion 25d, a portion 25e having a concavity directed towards the center of the exchanger 20 and a second rectilinear portion 25f.

[0110] The spacers 23, 24 each have a thickness of between 2mm and 4mm, for example equal to 3mm.

[0111] The exchanger 20 is a surface heat exchanger between a first fluid F1 and air F2. The fluid F1 is intended to circulate in the channels 25 and the air is intended to circulate in contact with the second smooth skin 22.

[0112] Thanks to the presence of spacers between the first and second skins 21, 22, the step of forming the first skin is eliminated.

[0113] In the example illustrated in Figure 3, the hydraulic interfaces 28, 29 are aligned along a longitudinal axis and the distribution channels 25 extend between said hydraulic interfaces 28, 29.

[0114] Alternatively, one could provide that the hydraulic interfaces

[0115] 28, 29 are aligned along another axis, for example a transverse axis, as illustrated in the example of figure 10, in which the same elements bear the same references.

[0116] Generally, the invention is not limited to the shape of the distribution channels, which are configured to extend between the inlet hydraulic interface 28 and the outlet hydraulic interface.

[0117] 29.

[0118] Figures 5 and 6 illustrate another embodiment which differs from the embodiment illustrated in Figures 3 and 4 only in that the first skin or sheet comprises a plurality of corrugations produced by forming said first skin.

[0119] As illustrated in Figures 5 and 6, a heat exchanger 30 comprises a first skin or sheet 31 and a second skin or sheet 32. The first skin 31 comprises a plurality of corrugations 35c and the second skin 32 is here flat.

[0120] The exchanger 30 comprises a plurality of distribution channels 35 each delimited by a corrugation 35c of the first corrugated skin 31 and the second skin 32 called smooth.

[0121] The exchanger 30 is a heat exchanger between a first fluid F1 and air F2. The fluid F1 is intended to circulate in the channels 35 and the air is intended to circulate in contact with the second smooth skin 32.

[0122] Each distribution channel 35 has a semicircular section.

[0123] As illustrated, the distribution channels 25 have a section of identical size between them.

[0124] Alternatively, different sized sections could be provided between each of the channels.

[0125] For example, it could be planned that the longest distribution channels have a larger cross-section in order to balance the flow rates between said distribution channels.

[0126] The distribution channels 25 are directly connected respectively to an inlet hydraulic interface 38 and to an outlet hydraulic interface 39.

[0127] In other words, there is no longer a collector and distributor located between the channels 35 and respectively the inlet 38 and outlet 39 hydraulic interfaces.

[0128] As illustrated in FIG. 5, the inlet ends 35a of the distribution channels 35 are distributed uniformly, that is to say regularly, over the entire periphery of the inlet hydraulic interface 38 and the outlet ends 35b of the distribution channels 35 are distributed uniformly over the entire periphery of the outlet hydraulic interface 39.

[0129] By "distributed over the entire circumference" is meant that an inlet end 35a of at least one channel 35 extends in a direction opposite to the outlet hydraulic interface 39 and that an outlet end 35b of at least one channel 35 extends in a direction opposite to the inlet hydraulic interface 38. The inlet ends 35a of the channels 35 and the outlet ends 35b of the channels 35 have a curved shape.

[0130] The concavity of the inlet ends 35a and the outlet ends 35b of the channels 35 is directed towards the center of the exchanger 30. The inlet ends 35a and the outlet ends 35b are connected to each other by a main part 35d, here rectilinear.

[0131] Alternatively, a more complex shape could be provided, such as that seen in Figure 10.

[0132] The first and second skins 31, 32 are assembled by a welding or brazing zone 36, 37 on either side of the corrugation 35c of the corrugated skin 31. Said welding or brazing zone 36, 37 extends from the first skin 31 to the second skin 32.

[0133] Generally, the first skin 21, 31 has a thickness of between 1 and 2 mm and the second skin 22, 32 has a thickness of between 0.6 and 2 mm.

[0134] The first skin and / or the second skin 21, 31; 22, 32 is made of aluminum or an alloy comprising aluminum. This makes it possible to improve the lightness, thermal exchanges and formability of the skins.

[0135] The exchanger is, for example, watertight up to the Obars.

[0136] The heat exchangers 20, 30 described above are advantageously intended to equip a nacelle 40 of a turbomachine 50 or aircraft engine visible in FIG. 9.

[0137] In Figure 9 is shown very schematically an axial section of a turbomachine 50, of general longitudinal axis X-X', for example of the double-flow and double-spool turbojet type comprising a fan 51, coupled to a gas turbine engine comprising a low-pressure compressor 52, a high-pressure compressor 53, an annular combustion chamber 54, a high-pressure turbine 55 and a low-pressure turbine 56.

[0138] The rotors of the high-pressure compressor and the high-pressure turbine are connected by a high-pressure (HP) shaft (not shown) and form with it a high-pressure body. The rotors of the low-pressure compressor and the low-pressure turbine are connected by a low-pressure (LP) shaft (not shown) and form with it a low-pressure body. The HP and LP shafts extend along a longitudinal axis X-X' of the turbomachine 50.

[0139] The fan shaft is rotatably connected to the LP shaft directly or indirectly.

[0140] It will be noted that the invention is not limited to such a turbomachine structure and could be applied to a turbomachine of different structure, for example to a turbomachine of the double-flow turbojet type, in which the low-pressure compressor acts as a fan.

[0141] The nacelle 40 of the turbomachine comprises a housing 41 for the turbomachine 50 and has a tubular structure comprising an external fairing 42 defining an external aerodynamic surface and an internal fairing 43 defining an internal aerodynamic flow surface through the turbomachine 50 and in particular the fan 51.

[0142] The external and internal fairings 42, 43 are connected upstream by an air inlet lip wall 44 forming a leading edge of the nacelle 40.

[0143] The external and internal fairings 42, 43 delimit an external structure usually comprising a fixed part and a mobile part (not shown), such as for example thrust reversal means.

[0144] The nacelle 40 further comprises a fixed internal structure 45, called “inner fixed structure”, with the acronym “IFS” in English terms. The fixed internal structure 45 is concentric with the external structure, at a downstream section and surrounds the core of the turbojet engine 50 downstream of the fan 51.

[0145] These external and internal structures define an annular flow vein, called secondary vein VS, aimed at channeling a flow of cold air, called secondary, circulating outside the turbomachine 50.

[0146] Downstream of the fan 51, the main air flow F is separated by the fixed internal structure 45 of the nacelle, here acting as a separation member, into a primary air flow FP and a secondary air flow FS. The primary air flow FP travels through an internal passage or primary vein VP when entering the low-pressure compressor 52, for example at the level of inlet guide vanes 57 or “inlet guide vanes”, acronym IGV in English terms.

[0147] The secondary air flow FS passes through an external annular passage or secondary vein VS, for example towards outlet guide vanes 58 or "outlet guide vanes", acronym OGV in English terms, then towards the outlet of the turbomachine.

[0148] The nacelle 40 is equipped with a heat exchanger 20, 30, fixed here on the internal surface of the internal fairing 43. Thus, the heat exchanger 20, 30 is fixed in the secondary vein VS, so that the air flow circulating in the secondary vein VS is in contact with the second skin 22, 32 of the heat exchanger 20, 30.

[0149] Alternatively, it could be provided that the heat exchanger 20, 30 is fixed here on the external surface of the internal structure 45 of the nacelle 40.

[0150] According to another variant, the heat exchanger 20, 30 can be fixed on the external surface of the external fairing 42 of the nacelle 40. Thus, the heat exchanger 20, 30 can be used to cool a fluid from the secondary flow FS or from the outside air.

[0151] According to yet another variant, the heat exchanger 20, 30 could be fixed on the internal surface of the internal structure 45, that is to say in the fluid flow of the primary vein VP.

[0152] Thus, the heat exchanger 20, 30 can be used to heat a fluid from the primary flow FP.

[0153] The cooling air circulates through the exchanger, in particular the second skin 22, 32 called smooth where it recovers part of the thermal energy from the heat transfer fluid.

[0154] Thanks to the invention, the thermal exchanges between a fluid circulating in the heat exchanger and the air circulating outside said heat exchanger are optimized, while improving the structural strength of the heat exchanger and reducing aerodynamic pressure losses.

[0155] Furthermore, the absence of a distributor and collector improves the ease of forming the distribution channels, or even makes it possible to eliminate this forming operation, and reduces and homogenizes hydraulic pressure losses.

Claims

CLAIMS 1. Turbomachine nacelle (40) comprising an external structure (42, 43) and an internal structure (45) delimiting an annular secondary flow vein (VS), said nacelle (40) comprising a housing for a turbomachine (50), which delimits with the internal structure (45) an annular primary flow vein (VP), the nacelle comprising at least one surface heat exchanger (20, 30) fixed either on the external structure (42, 43), on the side of the secondary flow vein (VS) or on the side external to said external structure (42, 43), or on the internal structure (45), on the side of the secondary flow vein (VS) or on the side of the primary flow vein (VP), the surface heat exchanger (20, 30) comprising a first sheet (21, 31) and a second sheet (22, 32) assembled together and at least three distribution channels (25, 35) arranged between the first sheet (21, 31) and the second sheet (22, 32), the exchanger further comprising a hydraulic inlet interface (28,38) and an outlet hydraulic interface (29, 39), each of the distribution channels (25, 35) being directly connected to the inlet hydraulic interface (28, 38) and to the outlet hydraulic interface (29, 39), characterized in that the distribution channels (25, 35) are regularly distributed over the entire circumference of the inlet hydraulic interface (28, 38) and / or the outlet hydraulic interface (29, 39) and in that the distribution channels (25, 35) each comprising an inlet end (25a, 25b) and an outlet end (25b, 35b) each having a curved shape., 2. Nacelle (40) according to claim 1, in which the distribution channels (25, 35) have an identical section between them.

3. Nacelle (40) according to claim 1, in which the distribution channels (25, 35) have a different section between them.

4. Nacelle (40) according to any one of the preceding claims, comprising a plurality of spacing members (23, 24) arranged between the first sheet (21) and the second sheet (22), two adjacent spacing members (23, 24) delimiting a distribution channel (25).

5. Nacelle (40) according to claim 4, in which the first sheet (21) and the second sheet (22) are assembled together by an assembly zone (26, 27) at the level of the spacing members (23, 24), said assembly zone (26, 27) extending from the first sheet (21) to the second sheet (22).

6. Nacelle (40) according to any one of claims 1 to 3, in which the first sheet (31) comprises a plurality of corrugations (35c), the distribution channels (35) each being delimited by a corrugation (35c) of the first corrugated sheet (31) and the second sheet (32).

7. Nacelle (40) according to claim 6, in which each distribution channel (35) has a semicircular section.

8. Nacelle (40) according to any one of the preceding claims, in which the exchanger (20, 30) comprises an axis of symmetry (S l -S l ) passing through the inlet hydraulic interface (28) and the outlet hydraulic interface (29), the distribution channels (25, 35) being arranged symmetrically with respect to said axis of symmetry (SI , SI ).

9. Nacelle (40) according to any one of the preceding claims, in which the hydraulic inlet (28, 38) and outlet (29, 39) interfaces have a circular section and each comprise an outlet orifice extending along a plane perpendicular to the extension planes of the sheets (21, 31; 22, 32).

10. Nacelle (40) according to any one of the preceding claims, in which the thickness of each distribution channel (25, 35) is constant over the entire length of the corresponding channel.

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