Heat exchange system for aircraft turbine engine

Abstract

The present application relates to a heat exchange system (20), in particular for an aircraft turbine engine (1), comprising:-two annular walls extending around one another and around the same axis (X) and configured to define therebetween a flow duct (V2) for an air flow (F2); -first annular heat exchange means (21) carried by one of the walls (22) and located in the duct (V2), the first means (21) occupying at most 75% or even at most 50% of the height (H) of the duct (V2); and-second annular heat exchange means (30) carried by the other of the walls (23) and located in the duct (V2), the second means (30) occupying at most 75% or even at most 50% of the height (H ') of the duct (V2).

Description

Technical Field

[0001] The present invention generally relates to the field of cooling and has particular application in the field of aviation. The present invention is directed in particular to a heat exchange system, in particular for a turbine engine, in particular for aircraft. Background Art

[0002] The prior art includes, inter alia, the following documents: GB-A-2 596 433, US-B1-6,668,915, FR-A1-3093765 and US-A1-2008 / 095611.

[0003] Turbine engines, in particular for aircraft, include various components and / or devices that require lubrication and / or cooling, such as rolling bearings and gears. Depending on the power of the components and / or devices, the heat released by these components can be quite high, which is transported via a fluid and discharged towards an available cooling source in the aircraft.

[0004] It is known to equip turbine engines with one or more heat exchange systems for exchanging heat between a fluid (usually oil) and a cooling source (air, fuel, etc.). There are even different types of heat exchange systems, such as fuel / oil heat exchangers, often referred to by the acronym FCOC (Fuel Cooled Oil Cooler), and air / oil heat exchangers, referred to by the acronym ACOC (Air-Cooled Oil Cooler).

[0005] The FCOC heat exchanger has a dual function: heating the fuel before combustion in the turbine engine's combustion chamber and cooling the oil heated by the turbine engine's radiated heat. However, the FCOC heat exchanger is not sufficient to absorb all the radiated heat because the temperature of the fuel is limited for safety reasons.

[0006] Additional cooling is achieved by ACOC heat exchangers, in particular surface heat exchangers denoted by the acronym SACOC. Surface heat exchangers are typically arranged in the secondary ducts of a turbine engine and use the secondary air flow to cool the oil circulating in the turbine engine. These heat exchangers are in the form of metal surface components that allow the oil to pass through machined channels. The secondary air flow is guided along a heat exchange matrix carried by the surface component, which serves to increase the contact surface with the secondary air flow and absorb heat. However, a disadvantage of SACOC heat exchangers is that they cause additional pressure losses in the associated secondary ducts because they disrupt the air flow, which has an impact on the performance and specific fuel consumption of the turbine engine.

[0007] The applicant has proposed a solution to this problem in documents FR-A1-3 096 409 and FR-A1-3 096 444.

[0008] Furthermore, due to the need for higher speed and power requirements to meet specification trends on turbine engines, cooling requirements for the lubrication fluid are increasing.

[0009] In fact, ACOC heat exchangers are increasingly used in next generation engines due to the significant increase in dissipated heat, mainly due to:

[0010] - Future engines will be larger, which increases the demand for lubrication and oil cooling,

[0011] - the presence of a reduction gear in new engine architectures, as this transmits very high mechanical power and requires oil lubrication and cooling, and

[0012] -Adding electric motors to the engine to achieve hybrid power requires oil lubrication and cooling.

[0013] An engine may include multiple oil circuits, each with a specific function, such as a first circuit for cooling oil used exclusively for lubricating and cooling the engine, a second circuit for lubricating and cooling the motor reduction gears, a third circuit for cooling the electric motor, and so on. Temperature and oil flow rates must be controlled according to the respective circuits. For example, the temperature range of the oil used to lubricate and cool the electric motor differs from that of the oil used to cool the engine. Therefore, the ACOC is preferably divided into several exchangers, each dedicated to a specific oil circuit. These various heat exchangers are typically distributed around the longitudinal axis of the engine.

[0014] The increasing demand for cooling has a direct impact on the size of the ACOC. Therefore, a large exchanger is desirable to remove a significant amount of oil heat. To remove oil heat, the ACOC may occupy all available space in the duct and therefore extend around the duct and across its entire height or radial dimension to achieve the necessary air flow rate to remove the significant amount of heat at the sizing point, which typically occurs during takeoff in extremely hot weather.

[0015] However, the fact that the ACOC exchanger occupies the entire radial height of the duct does not make it possible to use the solutions described in documents FR-A1-3 096 409 and FR-A1-3 096 444 to control the flow through the exchanger.

[0016] As a result, all airflow passes through the ACOCs, and each ACOC operates at suboptimal aerodynamic thermal performance. This causes a high pressure drop on the air side, resulting in inefficient heat exchangers.

[0017] The object of the present invention is to propose an improvement over the prior art, optimizing the efficiency of the heat exchange while avoiding pressure losses and disturbing the air flow as little as possible. Summary of the Invention

[0018] Therefore, the present invention proposes a heat exchange system, in particular a heat exchange system for an aircraft turbine engine, comprising:

[0019] two annular walls, respectively an outer wall and an inner wall, extending around one another and around the same axis and configured to define between them a flow duct for the air flow,

[0020] a first annular heat exchange device extending around the axis and carried by one of the walls and located in the duct, the first device occupying at most 75% of the height of the duct, the height being measured in the radial direction in the region of the duct in which the first device is located,

[0021] Characterized in that, the heat exchange system further comprises:

[0022] - a second annular heat exchange device, which extends around the axis and is carried by another of the walls and is located in the duct, the second device occupying at most 75% of the height of the duct, the height being measured in radial direction in the region of the duct in which the second device is located.

[0023] Therefore, the invention proposes combining at least two annular heat exchange devices in the same annular duct of the air flow. Each wall of the system has a device that extends only part of the height or radial dimension of the duct, which makes it possible to limit the impact of the device on the air flow and thus the pressure drop.

[0024] The heat exchange system may include one or more of the following features, which may be considered independently or in combination:

[0025] - the devices are axially spaced apart from one another in the duct;

[0026] - the devices overlap each other axially in the duct;

[0027] - the system comprises a third annular heat exchange device, preferably extending around the axis and located in the duct;

[0028] - said third means are situated at a radial distance from said wall and occupy at most 50% of the height of said duct, said height being measured in the radial direction in the region of the duct in which said third means are situated;

[0029] - the third device is located axially between the first device and the second device;

[0030] - the first device and the third device overlap each other axially in the duct, and / or the third device and the second device overlap each other axially in the duct;

[0031] - said third means extend between said walls and are connected to these walls, for example by means of fixing arms;

[0032] The device is of the air-to-oil type and comprises an oil circuit and a heat exchange matrix, which is located in the duct and is configured to be swept by the airflow; in the present application, the heat exchange matrix may comprise fins and / or plate portions and / or tube portions. The matrix may be layered and, for example, comprise a stack of multiple layers, each layer comprising a fin or at least one plate portion or at least one tube portion. The fins are designed to be swept by the airflow, and the plate portions or tube portions are, for example, traversed by the oil circuit or comprise such an oil circuit;

[0033] The heat exchange matrix of each of the first and second devices is covered by an annular fairing, the annular fairing comprising a first end portion and a second end portion, the first end portion being located upstream of the heat exchange matrix with respect to the flow of the airflow and having a diverging shape with respect to the airflow, and the second end portion being located downstream of the heat exchange matrix with respect to the flow of the airflow and having a convergent shape with respect to the airflow;

[0034] - the heat exchange matrices of the first and second devices are axially spaced apart, and the second end of the fairing of one of the first and second devices axially overlaps the first end of the fairing of the other of the first and second devices;

[0035] - the heat exchange matrix of the third device is sandwiched between two annular fairings, said two annular fairings being independent of and at a distance from the fairings of the first and second devices;

[0036] The heat exchange matrix of the third device is sandwiched between two annular fairings, a first fairing of the two annular fairings being connected to the fairing of the first device or forming the fairing of the first device, and a second fairing of the two annular fairings being connected to the fairing of the second device or forming the fairing of the second device;

[0037] - each of said devices occupies at least 10% of said height of the duct;

[0038] - each of said devices comprises a single heat exchanger, or each of said devices is segmented and comprises two or more heat exchangers distributed around said axis;

[0039] --Each device is of ACOC or SACOC type;

[0040] - the or each fairing comprises end portions respectively an upstream end portion and a downstream end portion, the upstream end portion and the downstream end portion forming a diverging section and a converging section respectively;

[0041] Each of the converging shape and the diverging shape has a frustoconical or rounded shape; the rounded shape can improve the aerodynamics of the flow around the device, which reduces the pressure drop caused by installing the component. These shapes can be obtained, for example, by additive manufacturing;

[0042] - the first heat exchange device is of surface type, and / or the second heat exchange device is of surface type, and / or the third heat exchange device is of surface type;

[0043] - the or each heat exchange device is of the SACOC or ACOC type;

[0044] the or each fairing being at a distance from the wall of the duct such that a portion of the airflow flowing in the duct can bypass the or each heat exchange device;

[0045] - said first means occupy at most 50% of the height of said duct,

[0046] - the second means occupies at most 50% of the height of the duct,

[0047] The present invention also relates to a turbine engine or electronic equipment comprising at least one heat exchange system as described above. The present invention can be used to cool electronic equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The invention will be better understood and other objects, details, features and advantages of the invention will become clearer from the following detailed explanatory description of an embodiment of the invention given as a purely illustrative and non-limiting example with reference to the attached schematic drawings, in which:

[0049] [ Figure 1 ] Figure 1 is a schematic half view of an axial section of an example of a turbine engine to which the present invention is applied;

[0050] [ Figure 2 ] Figure 2 is a schematic cross-sectional view of a heat exchange system;

[0051] [ Figure 3 ] Figure 3 Shown Figure 2 a schematic axial cross section of the system shown;

[0052] [ Figure 4 ] Figure 4 For Figure 3 Another schematic diagram of a similar system;

[0053] [ Figure 5 ] Figure 5 is a partial schematic perspective view of a heat exchange device;

[0054] [Figures 6a-6b] Figures 6a and 6b are schematic cross-sectional views of heat exchange systems, each of which includes a segmented heat exchange device;

[0055] [ Figure 7 ] Figure 7 is a schematic axial cross-sectional view of the system in FIG6 a;

[0056] [ Figure 8 ] Figure 8 is a schematic axial cross-sectional view of a heat exchange system according to a first embodiment of the present invention;

[0057] [ Figure 9 ] Figure 9 is a schematic axial cross-sectional view of a heat exchange system according to a second embodiment of the present invention;

[0058] [ Figure 10 ] Figure 10 is a schematic axial cross-sectional view of a heat exchange system according to a third embodiment of the present invention;

[0059] [ Figure 11 ] Figure 11 is a schematic axial cross-sectional view of a heat exchange system according to a fourth embodiment of the present invention;

[0060] [ Figure 12 ] Figure 12 is a schematic axial cross-sectional view of a heat exchange system according to a fifth embodiment of the present invention;

[0061] [ Figure 13 ] Figure 13 is a schematic axial cross-sectional view of a heat exchange system according to a sixth embodiment of the present invention;

[0062] [ Figure 14 ] Figure 14 is a schematic axial cross-sectional view of a heat exchange system according to a seventh embodiment of the present invention. DETAILED DESCRIPTION

[0063] Figure 1 Shown is an axial section through a turbine engine with a longitudinal axis X to which the invention applies. The turbine engine shown is a twin-flow turbine engine 1 intended to be installed on an aircraft. Of course, the invention is not limited to this type of turbine engine.

[0064] The twin-flow turbine engine 1 generally comprises a gas generator 2 , with a fan or a fan module 3 installed upstream of the gas generator 2 .

[0065] In the present invention, the terms “upstream” and “downstream” are defined relative to the gas flow in the turbine engine 1 and here along the longitudinal axis X.

[0066] The gas generator 2 comprises a gas compressor assembly (here comprising a low-pressure compressor 4a and a high-pressure compressor 4b), a combustion chamber 5 and a turbine assembly (here comprising a high-pressure turbine 6a and a low-pressure turbine 6b).

[0067] Typically, the turbine engine 1 includes a low-pressure shaft 7 connecting a low-pressure compressor 4a and a low-pressure turbine 6a to form a low-pressure body, and a high-pressure shaft 8 connecting a high-pressure compressor 4b and a high-pressure turbine 6b to form a high-pressure body.

[0068] A low-pressure shaft 7 centered on the longitudinal axis X drives the fan shaft 9 via a reduction gear 10. Rotary guide bearings 15 can also be used to rotationally guide the low-pressure shaft 7 relative to the stationary structure or stator of the turbine engine. The high-pressure shaft 8 is also rotationally guided by guide bearings (not shown).

[0069] The fan 3 is located in a duct in a fan housing 11 carried by the nacelle 12 and generates a primary air flow F1 that circulates through the gas generator 2 in a primary duct V1 and a secondary air flow F2 that circulates around the gas generator 2 in a secondary duct V2 .

[0070] The secondary air flow F2 is injected by a secondary nozzle 13 at the end of the nacelle, while the primary air flow F1 is injected to the outside of the turbine engine 1 via an injection nozzle 14 located downstream of the gas generator 2 .

[0071] In the following description, the fan case 11 and the nacelle 12 are considered to be a single piece.

[0072] In this exemplary configuration of turbine engine 1, guide bearing 15 and reduction gear 10 must be lubricated and / or cooled to ensure the performance of turbine engine 1. The energy generated thereby is dissipated into a fluid from a fluid supply source installed in turbine engine 1, which is used to lubricate and / or cool various components and / or equipment in turbine engine 1. Of course, other equipment in turbine engine 1 generates a significant amount of heat, which needs to be extracted from its environment.

[0073] To this end, the turbine engine 1 comprises a heat exchange system 20 which enables the fluid configured to lubricate and / or cool these components and / or devices to be cooled. In this example, the fluid is oil, and the cold source for cooling the oil is the air flow circulating in the turbine engine, in particular the secondary air flow F2.

[0074] In the context of the present invention, the heat exchange system 20 refers to a system comprising the following components:

[0075] two annular walls, respectively an outer wall and an inner wall, extending around each other and around the same axis and configured to define between them a flow duct for the air flow, and

[0076] - At least one annular heat exchange device located in the duct.

[0077] exist Figure 1 For example, the heat exchange system 20 of the turbine engine 1 includes: an outer wall 22 formed by the fan casing 11 and / or the nacelle 12, an inner wall 23 formed by the casing of the gas generator 2, and a heat exchange device 21 supported by the outer wall 22 and located in the duct V2.

[0078] The heat exchange device 21 is, for example, a surface type (eg, SACOC type), preferably an air / oil type.

[0079] Device 21 includes an oil circuit and a heat exchange matrix located in duct V2 and configured to be swept by airflow F2. As described above, the heat exchange matrix may include fins and / or plates and / or tubes. The matrix may be layered, for example, comprising a stack of multiple layers, each layer including fins, at least one plate, or at least one tube. The fins are designed to be swept by the airflow, and the plates or tubes, for example, are passed through by the oil circuit or include such an oil circuit.

[0080] Figure 2 and Figure 3 This type of heat exchange system 20 is schematically shown. As can be seen, the heat exchange device 21 of this system 20 is annular and extends continuously around the axis X over 360°.

[0081] It can also be seen that it occupies only a portion of the height H of the duct V2. The height h or radial dimension of the device 21 is only a portion of the height H or radial dimension of the duct V2. These heights H, h are measured in the radial direction relative to the axis X in the area of ​​the duct V2 where the device 21 is located. The height H of the duct V2 can vary along the axis X.

[0082] One of the problems observed in this type of device 21 is the turbulence and pressure losses generated in the air flow F2 , with the effect of increasing the specific fuel consumption of the turbine engine 1 . Optimizing the aerodynamic thermal performance of this system 20 is therefore very important.

[0083] In the document mentioned above, the applicant proposed a solution for optimizing the integration of this type of device 21 in a duct. Figure 4 . The concept is to slow the velocity of the airflow through device 21. The airflow through device 21 is highly turbulent. Slowing the velocity of the airflow entering device 21 optimizes its aerodynamic thermal performance, thereby minimizing the pressure drop for a given amount of heat dissipation. Control of the flow through device 21 can be achieved by combining device 21 with a diverging section 24 and a converging section 25 at the inlet. The diverging section 24 upstream of device 21 is configured to compress and decelerate the airflow entering device 21, while the converging section 25 downstream of device 21 is configured to accelerate and expand the airflow exiting the device. At the inlet of device 21, the deceleration factor is inversely proportional to the height ratio h / h0, where h is the height as described above and h0 is the height at the inlet of diverging section 24. Note that the slower the flow, the lower the pressure drop generated by device 21. At the outlet of device 21, the acceleration factor is inversely proportional to the height ratio h / h3, where h3 is the height at the outlet of converging section 25.

[0084] Figure 5 A perspective view of a portion of a heat exchange device 21 is shown. The figure shows a heat exchange matrix 26, which is sandwiched between a fairing 27 and the walls 22, 23 carrying the device 21. The converging portion 25 and the diverging portion 24 may be formed by the ends of the fairing 26, as in the example shown.

[0085] exist Figure 5 In the figures and other drawings, arrows are used to schematically indicate the oil circuit 28 .

[0086] 6a and 6b schematically illustrate alternative examples of heat exchange systems 20. In the embodiment of FIG.

[0087] In the case of FIG. 6 a , the system 20 comprises an annular heat exchange device 21 which is segmented and comprises two sectors, each sector having an angular extent of approximately 180°.

[0088] In the case of FIG. 6 b , the system 20 comprises an annular heat exchange device 21 which is segmented and comprises four sectors, each sector having an angular extent of approximately 90°.

[0089] In Figures 6a-6b, the heat exchange device 21 extends over the entire height H of the duct and is connected to the two walls 22, 23. The height h of the device 21 is then equal to the height H of the duct ( Figure 7 ).

[0090] The present invention is an improvement to this technology and provides a number of embodiments. Figure 8 and shown below.

[0091] One of the characteristics of the invention is that the heat exchange system comprises at least two separate annular heat exchange devices and that each of these devices occupies at most 75% or even at most 50% of the height of the duct in which they are installed.

[0092] exist Figure 8 In the illustrated first embodiment of the present invention, the heat exchange system 20 comprises:

[0093] two annular walls, respectively an outer wall 22 and an inner wall 23 , extending around one another and around the same axis X and configured to define between them a flow duct V2 for an airflow (for example, the secondary flow F2 ),

[0094] a first annular heat exchange device 21 extending about the axis X and carried by one of the walls (in the case of the figure, the outer wall 22) and situated in the duct V2, this first device 21 occupying at most 75% or even at most 50% of the height H of the duct V2, this height H being measured in the radial direction in the region of the duct V2 in which this first device 21 is situated, and

[0095] - a second annular heat exchange device 30, which extends around the axis X and is carried by another of the walls (in the case of the figure, the inner wall 23) and is located in the duct V2, the second device 30 occupying at most 75% or even at most 50% of the height H' of the duct V2, the height H' being measured in the radial direction in the region of the duct in which the second device is located.

[0096] Figure 8 The devices 21 , 30 are shown axially spaced apart in the duct V2 . They are spaced apart by an axial distance L. The device 21 on the outer wall 22 is located upstream of the device 30 on the inner wall 23 .

[0097] Preferably, these devices 21 , 30 are of the air-oil type and are, for example, surface mounted, and each device comprises an oil circuit 28 and a heat exchange matrix 26 situated in the duct V2 and configured to be swept by the air flow F2 , as described above.

[0098] The heat exchange matrix 26 of each device 21, 30 is covered by an annular fairing 27, which includes a first end 27a and a second end 27b, the first end being located upstream of the heat exchange matrix 26 with respect to the flow of the airflow F2 and having a divergent shape with respect to this airflow F2, and the second end being located downstream of the heat exchange matrix 26 with respect to the flow of the airflow F2 and having a convergent shape with respect to this airflow F2.

[0099] In the example shown, the ends 27a, 27b each have a frustoconical shape.

[0100] As mentioned above, each of the devices 21 , 30 may comprise a single heat exchanger, or may be segmented and comprise two or more heat exchangers distributed around the axis X.

[0101] In the example shown, the first device 21 on the left side of the figure is an upstream device and occupies a height h in the duct between 20% and 50% of the height H. The second device 30 on the right side of the figure is a downstream device and occupies a height h' in the duct between 20% and 50% of the height H'.

[0102] The height difference Hh may be equal to or different from the height difference H'-h'. In addition, h' may be greater than or less than h.

[0103] It will be understood that the outer portion of the air flow F2 flowing in the duct (e.g., 5% to 30% of the flow) will enter the device 21, while the remaining portion will bypass the device 21. Of the remaining portion, the inner portion will pass through the device 30 (e.g., 5% to 30% of the flow), while the remaining middle portion of the flow will bypass the device 30.

[0104] Device 30 is therefore traversed by a different flow of exhaust air than device 21. Indeed, one advantage of mounting the two devices on opposite sides of the duct is that the air flow leaving the first device does not have to be used for heat exchange in the second device, since the air flowing out of the first device is heated by the oil and therefore has a low cooling potential. This means that the air entering each device has the same temperature (to the nearest Kelvin) as the air entering the duct.

[0105] Alternatively, if the devices 21 , 30 overlap in the axial direction, L may be zero or a negative value.

[0106] Figure 9 The second embodiment shown differs from the first embodiment in that the means 21 on the outer wall 22 are located downstream of the means 30 on the inner wall 23 .

[0107] The devices 21 , 30 are axially spaced apart from each other by a distance, denoted L0 , which may be close to zero or even equal to zero (hence zero), ie the devices 21 , 30 may be arranged directly one after the other in the duct V2 .

[0108] Furthermore, the ends 27a and 27b of the fairing 28 are curved rather than frusto-conical.

[0109] It will be understood that the inner portion of the air flow F2 flowing in the duct will enter the device 30, while the remaining portion will bypass the device 30. Of this remaining portion, the outer portion will pass through the device 21, while the remaining middle portion of the flow will bypass the device 21.

[0110] Alternatively, L0 may be positive and non-zero, or negative in the case where the devices 21 , 30 overlap axially.

[0111] Figure 10 The third embodiment shown in FIG differs from the second embodiment in that the devices 21 , 30 are even closer together in the axial direction and even overlap each other in the axial direction.

[0112] The heat exchange matrices 26 of the devices 21 , 30 are axially spaced apart from each other. The downstream end 27b of the fairing 27 of the device 30 axially overlaps the upstream end 27a of the fairing 27 of the device 21 .

[0113] The operation of this embodiment is similar to Figure 9 Operation of the embodiment.

[0114] The overlap results in a more gradual change in the passage cross section of the flow around the two devices, thereby avoiding significant changes in the flow velocity profile around the devices as the flow passes through the area where the two devices are located.

[0115] Figure 11 The fourth embodiment shown differs from the second embodiment in that the device 30 is segmented and comprises two or more heat exchangers distributed around the axis X. This principle has been explained above and illustrated in Figures 6a and 6b, for example.

[0116] The device 21 may also be segmented.

[0117] The operation of this embodiment is similar to Figure 9 Operation of the embodiment.

[0118] Figure 12 The embodiments shown in the following figures differ from the preceding embodiments in particular in that they comprise a third annular heat exchange device 40 extending around the axis X and situated in the duct V2 .

[0119] exist Figure 12In the fifth embodiment shown, the devices 21 and 30 are similar to Figure 8 The third device 40 is situated at a radial distance from the walls 22 , 23 and occupies at most 75% or even at most 50% of the height H″ of the duct V2 , this height H″ being measured in the radial direction in the region of the duct V2 in which this third device 40 is situated.

[0120] The third device 40 is located between the first and second devices 21 , 30 in the axial direction.

[0121] The first and third devices 21 , 40 may be axially spaced apart from one another, may be located directly behind one another, or may axially overlap one another in the duct.

[0122] Similarly, the third and second devices 40, 30 may be axially spaced apart from one another, may be located directly behind one another, or may axially overlap one another in the duct.

[0123] The third device 40 comprises a heat exchange matrix 41 sandwiched between two annular fairings, respectively an inner fairing 42 and an outer fairing 43 .

[0124] In the example shown, the fairings 42 , 43 are separate from the fairings 27 of the first and second devices 21 , 30 and are spaced apart from the fairings of the first and second devices.

[0125] Similar to the fairing 27 on the devices 21 , 30 , the fairings 42 , 43 on the device 40 may be curved, or alternatively, frusto-conical.

[0126] The height difference Hh may be equal to the height difference H'-h', or may be equal to the height difference H"-h", as schematically shown in the drawings.

[0127] It will be understood that the peripheral portion of the air flow F2 flowing in the duct will enter the device 21, while the remaining portion will bypass the device 21. A central portion of this remaining portion will enter the device 40, while the peripheral portion of the flow will bypass the device 40. The inner peripheral portion of the remaining portion will partially enter the device 30, and the remaining portion will bypass the device 30 to join the peripheral portion of the flow bypassing the device 40.

[0128] exist Figure 13 In the sixth embodiment shown, the devices 21 and 30 are similar to Figure 9 A third device 40 extends between the walls 22 , 23 and is connected to these walls 22 , 23 .

[0129] In the example shown, the third device 40 is located upstream of the devices 21 , 30 .

[0130] Said third device 40 comprises a heat exchange matrix 41 directly connected to the walls 22, 23. The height h" of the third device 40 is therefore equal to the height H" of the duct V2.

[0131] It will be appreciated that the entire air flow F2 enters the device 40. An inner portion of the flow will then enter the device 30, while the remainder will bypass the device 30. An outer portion of this remainder will pass through the device 21, while the remainder will bypass it.

[0132] This is a hybrid (serial / parallel) mounting configuration, where the third device 40 is mounted in series with two other devices 21 , 30 , which are in turn mounted in parallel.

[0133] exist Figure 14 In the seventh embodiment shown, the devices 21 and 30 are similar to Figure 8 The third device 40 is located axially between the first and second devices 21,30.

[0134] It can also be seen that the third device 40 is located radially between the first and second devices 21 , 30 .

[0135] The third device 40 comprises a heat exchange matrix 41 sandwiched between two annular fairings, the inner fairing of the device 40 being formed by the upstream end 27a of the fairing 27 of the device 30 and the outer fairing of the device 40 being formed by the downstream end 27b of the fairing 27 of the device 30 .

[0136] It can therefore be understood that the entire height of the duct is occupied by the devices 21 , 30 , 40 , since no part of the airflow F2 can bypass them and the entire airflow therefore participates in the exchange of calories with the oil in the circuit 28 .

[0137] It should be understood that the outer peripheral portion of the air flow F2 flowing in the duct will enter the device 21, while the remaining portion will bypass the device 21. The middle portion of the remaining portion will enter the device 40, and the inner peripheral portion of the remaining portion will enter the device 30, so that the entire air flow is used to participate in heat exchange with the device.

[0138] The present invention provides many advantages, including:

[0139] Improved aero-thermal performance of the devices: The proposed concept allows for optimized flow within each device from an aero-thermal perspective. The fact that the heat exchange system does not necessarily occupy the entire available radial height means that upstream / downstream divergent / convergent devices can better manage the flow within each exchanger without blocking the ducts and significantly slowing the flow through each device. This enables optimized aero-thermal performance of each device, reducing airside pressure drop and resulting in more efficient devices.

[0140] Mounting the devices on both sides of the duct wall results in the exhaust air being at the same temperature at the inlet of both devices, which is approximately the same as the duct inlet temperature. This avoids reusing the same heated air flow from the first exchanger to cool the oil in the second exchanger, thus improving the aerodynamic thermal performance of both devices.

[0141] ●The axial offset between the two devices allows the duct to leave space in the radial direction.

Claims

1. A heat exchange system (20), in particular for an aircraft turbine engine (1), comprising: - two annular walls, respectively an outer wall (22) and an inner wall (23), extending around one another and around the same axis (X) and configured to define between them a flow duct (V2) for the air flow (F2), and - a first annular heat exchange device (21) extending around the axis (X) and carried by one of the walls (22), and located in the duct (V2), the first device (21) occupying at most 75% of the height (H) of the duct (V2), the height (H) being measured in the radial direction in the region of the duct (V2) in which the first device (21) is located, Characterized in that, the heat exchange system further comprises: a second annular heat exchange device (30) extending around the axis (X) and carried by another of the walls (23), and located in the duct (V2), the second device (30) occupying at most 75% of the height (H') of the duct (V2), the height (H') being measured in the radial direction in the region of the duct (V2) in which the second device (30) is located, The heat exchange matrix (26) of each of the first and second devices (21, 30) is covered by an annular fairing (27), the annular fairing comprising a first end (27a) and a second end (27b), the first end being located upstream of the heat exchange matrix (26) relative to the flow of the airflow and having a divergent shape relative to the airflow (F2), and the second end being located downstream of the heat exchange matrix (26) relative to the flow of the airflow and having a convergent shape relative to the airflow (F2).

2. The heat exchange system (20) according to claim 1, characterized in that The devices (21, 30) are axially spaced apart from each other in the duct (V2).

3. The heat exchange system (20) according to claim 1, characterized in that The devices (20) overlap each other in the duct (V2) in the axial direction.

4. A heat exchange system (20) according to any one of the preceding claims, characterized in that The heat exchange system comprises a third annular heat exchange device (40), preferably of the surface type, extending around the axis (X) and located in the duct (V2).

5. The heat exchange system (20) according to claim 4, characterized in that The third device (40) is located at a radial distance from the wall (22, 23) and occupies at most 50% of the height (H") of the duct (V2), the height (H") being measured in the radial direction in the region of the duct (V2) where the third device (40) is located.

6. The heat exchange system (20) according to claim 5, characterized in that The third device (40) is axially located between the first device and the second device (21, 30); the first device and the third device (21, 40) overlap each other axially in the duct (V2), and / or the third device and the second device (40, 30) overlap each other axially in the duct (V2).

7. The heat exchange system (20) according to claim 4, characterized in that The third means (40) extends between the walls (22, 23) and is connected to these walls.

8. The heat exchange system (20) according to any one of claims 1 to 7, characterized in that: The device (21, 30, 40) is of air-oil type and comprises an oil circuit (28) and a heat exchange matrix (26, 41) located in the duct (V2) and configured to be swept by the air flow (F2).

9. The heat exchange system (20) according to claim 8 as appended to claim 3, characterized in that The heat exchange matrices (26) of the first and second devices (21, 30) are spaced apart in the axial direction, and a second end (27b) of a fairing (27) of one of the first and second devices (21, 30) overlaps in the axial direction with a first end (27a) of a fairing (27) of the other of the first and second devices (21, 30).

10. A heat exchange system (20) according to claim 8 as appended to claim 5 or 6, characterised in that The heat exchange matrix (41) of the third device (40) is sandwiched between two annular fairings (42, 43) which are independent of the fairings (27) of the first and second devices (21, 30) and are at a distance from the fairings of the first and second devices.

11. A heat exchange system (20) according to claim 8 when appended to claim 5 or 6, characterised in that The heat exchange matrix (41) of the third device (40) is sandwiched between two annular fairings, a first fairing of the two annular fairings being connected to the fairing of the first device (21) or forming the fairing (27) of the first device, and a second fairing of the two annular fairings being connected to the fairing of the second device (30) or forming the fairing (27) of the second device.

12. The heat exchange system (20) according to any one of claims 1 to 11, characterized in that: Each of the devices (21, 30, 40) occupies at least 10% of the height (H, H', H") of the duct (V2).

13. The heat exchange system (20) according to any one of claims 1 to 12, characterized in that: Each of the devices (21, 30, 40) comprises a single heat exchanger, or each of the devices is segmented and comprises two or more heat exchangers distributed around the axis (X).

14. The heat exchange system (20) according to any one of claims 1 to 13, characterized in that: The first device occupies at most 50% of the height of the duct, and the second device occupies at most 50% of the height of the duct.

15. The heat exchange system (20) according to any one of claims 1 to 14, characterized in that: Each of the converging shape and the diverging shape has a frustoconical or circular shape.

16. A turbine engine (1) or an electronic device comprising at least one heat exchange system (20) according to any one of claims 1 to 15.

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