Device and method for regulating the temperature of an aircraft power source using a heat transfer fluid in a power transmission system

Abstract

This device (19) for regulating the temperature of a power source (2) of an aircraft comprises a first cooling circuit (22) for a power transmission means (4) of the aircraft, the first cooling circuit (22) being intended to contain a first heat transfer fluid (6) and comprising a first heat exchanger (10) between said first heat transfer fluid (6) and an external environment (12) to the first cooling circuit (22), the device (19) further comprising a second cooling circuit (24) for the power source (2) intended to contain a second heat transfer fluid (14), the first heat transfer fluid (6) serving as a cold source for the second heat transfer fluid (14). Figure for the abbreviation: Fig 2

Description

Title of the invention: Device and method for regulating the temperature of an aircraft power source using a heat transfer fluid in a power transmission means technical field

[0001] The present invention relates to the regulation of the temperature of a power source of an aircraft.

[0002] In particular, the present invention relates to the use of a heat transfer fluid used to cool a power transmission means of an aircraft as an intermediate cold source for another heat transfer fluid used to cool the aircraft's power source.

[0003] In general, the invention applies to the temperature regulation of any aircraft component that can be cooled using an intermediate cold source. Prior art

[0004] An aircraft power source and / or power transmission means are often subjected to thermal stress due to the natural heating of their components or their proximity to heating elements. The operation of an aircraft power source or power transmission means therefore generally requires cooling of the thermally stressed parts using a heat transfer fluid to ensure optimal performance.

[0005] Generally speaking, a power source is, for example, a turboshaft engine, a turbogenerator, a piston engine, or an electric motor. An aircraft is, for example, a helicopter, an airplane, or any other type of aircraft. In a helicopter, the power transmission means is, for example, a main gearbox, which transmits the power supplied by the power source to the main rotor, a tail gearbox, or a gearbox for a tail rotor of the aircraft.

[0006] For an aircraft comprising a turbogenerator, that is to say comprising a tur-bomachine dedicated to driving an electric generator, for example for supplying electric motor thrusters, cooling can be done using a heat exchanger and a pump allowing the circulation of a heat transfer fluid in a cooling circuit.

[0007] Figure 1 shows a power source 2 and a power transmission means 4 of an aircraft according to the prior art. The cooling of the power transmission means 4 is achieved by circulating a first heat transfer fluid 6 in a first cooling circuit 8 comprising a first heat exchanger 10 between said first heat transfer fluid 6 and an external environment 12, the external environment 12 being external to the first cooling circuit 8. The first heat exchanger 10 is for example integrated into the fuselage of the aircraft, the positioning of the first heat exchanger 10 being able to generate leaks of the first heat transfer fluid 6 and disrupt the proper functioning of the cooling.

[0008] The cooling of the power source 2 is carried out with a second heat transfer fluid 14 in a second cooling circuit 16 comprising a second heat exchanger 18 between said second heat transfer fluid 14 and the external environment 12. The second heat exchanger 18 is for example carried by the power source 2.

[0009] In particular, there is no heat exchange between the first heat transfer fluid 6 and the second heat transfer fluid 14.

[0010] The external environment 12 acts as a permanent cold source. The external environment 12 is, for example, the air in which the aircraft operates or the fuel consumed by the power source 2.

[0011] These first and second heat exchangers 10 and 18 are generally referred to as ACOCs, for Air Cooled Oil Cooler, when the cold source consumed is the air in which the aircraft operates. They are generally referred to as FCOCs, for Fuel Cooled Oil Cooler, when the cold source consumed is the fuel from the power source 2.

[0012] The temperature of the first heat transfer fluid 6 is sometimes lower than the temperature of the second heat transfer fluid 14, while the flow rate of the first heat transfer fluid 6 on the first cooling circuit 8 is sometimes greater than the flow rate of the second heat transfer fluid 14 on the second cooling circuit 16.

[0013] Existing solutions, such as the one described above, involve a large number of heat exchangers between the external environment 12 and a heat transfer fluid in an aircraft cooling circuit. Heat exchangers are expensive, bulky, and heavy, making them difficult to integrate. The presence of heat exchangers also reduces accessibility to aircraft components and may require the use of multiple fans, which negatively impacts the reliability of the aircraft's propulsion system.

[0014] A heat exchanger using fuel as a cold source to cool a power source requires a certain fuel flow rate through the exchanger to sufficiently dissipate the heat transferred to the fuel. This implies a sufficiently high fuel consumption to allow for efficient cooling of the power source. This solution is therefore difficult to apply to a low-fuel-consumption power source, as the amount of fuel circulating would then be insufficient to achieve a satisfactory energy balance. to cool said power source.

[0015] An ACOC type heat exchanger linked to a power source requires sufficient space to allow the integration of the exchanger, air ducts ensuring its supply and a fan allowing the circulation of air through the ACOC exchanger.

[0016] In addition, the fan needs to be driven, usually by an electric motor or a mechanical power transmission shaft.

[0017] The presence of the ACOC type exchanger therefore generates design constraints and additional costs.

[0018] The second heat exchanger 18, located at a distance from the power source 2, creates difficulties in conveying the second heat transfer fluid 14 from the power source 2 to the second heat exchanger 18 and necessitates a second, longer cooling circuit 16. The length of the second cooling circuit 16 results in excess mass due to the weight of the pipes of the second cooling circuit 16 and the weight of the second heat transfer fluid 14 they contain. Finally, conveying the second heat transfer fluid 14 from the power source 2 to the second heat exchanger 18 can create pressure losses of the second heat transfer fluid 14 in the second cooling circuit 16. Description of the invention

[0019] The present invention therefore aims to overcome the aforementioned drawbacks and to provide an improvement in the motor integration of an aircraft propulsion system, in particular by optimizing the arrangement of the cooling systems of the components of said propulsion system.

[0020] The present invention relates to a temperature control device for an aircraft power source comprising a first cooling circuit for an aircraft power transmission means, the first cooling circuit being intended to contain a first heat transfer fluid and comprising a first heat exchanger between said first heat transfer fluid and an environment external to the first cooling circuit, a second cooling circuit for the power source intended to contain a second heat transfer fluid and comprising a second heat exchanger between the first heat transfer fluid and the second heat transfer fluid, the first heat transfer fluid serving as a cold source for the second heat transfer fluid.

[0021] The first heat transfer fluid is therefore used to transport the heat generated and lost by the power source, which is then extracted via the second heat transfer fluid to the external environment, allowing for the final removal of said heat generated and lost by the power source. The first heat transfer fluid then serves as a source intermediate cold for cooling the second heat transfer fluid.

[0022] Thus, the present invention makes it possible to reduce the number of heat exchangers between the external environment and a heat transfer fluid of an aircraft cooling circuit and thus makes it easier to access aircraft components and to reduce the number of fans.

[0023] Reducing the number of fans makes it possible to decrease the mass and cost of the propulsion system of an aircraft.

[0024] Furthermore, the present invention improves the reliability of the aircraft propulsion system and allows the thermal management of the aircraft propulsion system to be shared by the power transmission means and the aircraft power source.

[0025] Aircraft availability can also be improved when starting in cold weather by synchronizing the heating of the power source with the heating of the power transmission means through the use of the first and second cooling circuits in a heating circuit.

[0026] The present invention also improves the cleanliness of the second cooling circuit by limiting the presence of dead zones in the path of the second heat transfer fluid that could delay the transport of particles in the second cooling circuit. These dead zones are, for example, sections of the cooling circuit in which the heat transfer fluid circulates little and / or is poorly mixed.

[0027] Optionally, the present invention also makes it possible to simplify the aircraft's hydraulic circuit by allowing the removal of a hydraulic overpressure protection device and limiting the external hydraulic interfaces to the aircraft fuselage which can cause leakage problems and pass through several internal bulkheads in the aircraft fuselage.

[0028] Advantageously, the first cooling circuit comprises a closed circuit so as to circulate the first heat transfer fluid from the first heat exchanger to the power transmission means, and from the power transmission means to the first heat exchanger.

[0029] Preferably, the second cooling circuit comprises a closed circuit so as to circulate the second heat transfer fluid from the second heat exchanger to the power source, and from the power source to the second heat exchanger.

[0030] For example, the second heat exchanger performs a heat exchange between the first heat transfer fluid circulating from the power transmission means and the second heat transfer fluid circulating towards the power source.

[0031] In one embodiment, the first cooling circuit passes through the second heat exchanger in which the second heat transfer fluid circulates, so that the first heat transfer fluid cools the second heat transfer fluid.

[0032] According to one feature of the invention, the device includes a housing intended to be formed around the power source, the housing including an interface with the first cooling circuit and allowing the second heat exchanger to be integrated into said housing so as to allow heat exchange between the first heat transfer fluid and the second heat transfer fluid.

[0033] The present invention also relates to an aircraft propulsion assembly comprising a power source, a power transmission means and a temperature control device for a power source of an aircraft as defined above.

[0034] Advantageously, the power source of said propulsion assembly includes a thermal engine and / or an electric motor and the power transmission means of said propulsion assembly includes a transmission box.

[0035] The invention further relates to an aircraft comprising a power source, a power transmission means and a temperature control device for a power source of an aircraft as defined above and / or a propulsion assembly as defined above.

[0036] The present invention also relates to a method for regulating the temperature of an aircraft power source by means of a regulation device as defined above, the method comprising the following steps:

[0037] - Circulation of the first heat transfer fluid in the first cooling circuit dissement;

[0038] - Heat transfer from the first heat transfer fluid to the external environment of in order to cool the first heat transfer fluid;

[0039] - Heat transfer from the power transmission means to the first heat transfer fluid to cool the power transmission means;

[0040] - Circulation of the second heat transfer fluid in the second re circuit cooling;

[0041] - Heat transfer from the second heat transfer fluid to the first heat transfer fluid locotransfereur so as to cool the second heat transfer fluid;

[0042] - Heat transfer from the power source to the second fluid ca carrier in order to cool the power source. Brief description of the drawings

[0043] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example, and made with reference to the accompanying drawings in which:

[0044] [Fig. 1] which has already been mentioned, schematically illustrates a temperature control device for a power source and a means of power transmission according to the prior art;

[0045] [Fig.2] schematically illustrates a temperature regulation device for a power source according to the invention in a first embodiment;

[0046] [Fig.3] schematically illustrates a second embodiment of a temperature control device for a power source according to the invention;

[0047] [Fig.4] schematically illustrates a third embodiment of a temperature control device for a power source according to the invention;

[0048] [Fig.5] schematically illustrates a fourth embodiment of a temperature control device for a power source according to the invention;

[0049] [Fig. 6] schematically illustrates a fifth embodiment of a temperature control device for a power source according to the invention; and

[0050] [Fig.7] schematically illustrates the main steps of a method for regulating the temperature of a power source according to the invention. Detailed description of at least one embodiment

[0051] Figure 2 shows a propulsion system of an aircraft comprising a power source 2, a power transmission means 4 and a device 19 for regulating the temperature of the power source 2 according to a first embodiment.

[0052] The power source 2 is for example a turbomachine of the turbomotor type for driving a helicopter rotor or of the turbogenerator type for driving electric thrusters of an aircraft. It may also include a piston engine and / or an electric motor.

[0053] The power transmission means 4 includes, for example, a main transmission box of the aircraft and / or a rear transmission box and / or a transmission box of a tail rotor of the aircraft and / or an intermediate transmission box between the power source 2 and the main transmission box of the aircraft and / or an electric motor powered by an electric generator.

[0054] The aircraft is, for example, a helicopter. It can also be an airplane, an electrically powered aircraft, or a vertical takeoff and landing aircraft.

[0055] The propulsion assembly further includes a power transmission shaft 20 connecting the power source 2 and the power transmission means 4 of the aircraft.

[0056] In normal operation of the propulsion assembly, the power source 2 transmits a movement, for example in the form of rotation or torque, to the power transmission shaft 20 so that the power transmission shaft 20 transmits this movement by means of power transmission 4.

[0057] The power transmission means 4 can drive a rotor, which may be the main rotor of a helicopter. The power transmission means 4 may include housings for driving accessories, which may be a hydraulic pump, an alternator, or a rotor brake (not shown). The power transmission means 4 may be equipped with sensors monitoring the temperature and pressure of heat transfer fluids, a rotor speed sensor, a high-temperature warning system, and / or metal shavings detection systems.

[0058] In this first embodiment, the device 19 includes a first cooling circuit 22 for containing a first heat transfer fluid 6. In particular, the first cooling circuit 22 cools the aircraft's power transmission means 4. The first cooling circuit 22 is preferably closed.

[0059] The first heat transfer fluid 6 is, for example, oil, water with additives to increase its heat capacity, or any other heat transfer fluid. Advantageously, the first heat transfer fluid 6 is the oil circulating in a mechanical transmission element driven by the power source 2, for example, the main transmission of the helicopter. The first cooling circuit 22 includes, for example, metal pipes adapted for the circulation of the first heat transfer fluid 6. The first heat transfer fluid 6 is, for example, set in motion by a pump (not shown) in the first cooling circuit 22, thereby forcing the circulation of the first heat transfer fluid 6 within the first cooling circuit 22.

[0060] The first cooling circuit 22 further includes a first heat exchanger 10 intended to allow an exchange of heat and cold between the first heat transfer fluid 6 and an external environment 12 to the first cooling circuit 22.

[0061] The first heat transfer fluid 6 circulates from the first heat exchanger 10 to the power transmission means 4 and from said power transmission means 4 back to the first heat exchanger 10. The first heat exchanger 10, for example of the ACOC type, allows the use of a cold source, in this case the air of the external environment 12 in which the aircraft is operating, in order to cool the first heat transfer fluid 6, which then comprises oil. Advantageously, the external environment 12 is used continuously.

[0062] The first heat exchanger 10, in which the first heat transfer fluid 6, for example oil, circulates, and using the external environment 12 as a cold source, for example air, includes a first circuit (not shown) for the passage of the first heat transfer fluid 6 and a second circuit (not shown) for the passage of air from the external environment 12.

[0063] The first flow circuit includes an inlet for the first heat transfer fluid 6 to be cooled, an outlet for the first cooled heat transfer fluid 6, and a plurality of first heat transfer fluid 6 supply modules fluidly connected to said inlet for the first cooled heat transfer fluid 6 and outlet for the first cooled heat transfer fluid 6. Each first heat transfer fluid 6 supply module comprises walls and a plurality of first heat transfer fluid 6 supply module fins.

[0064] The second air supply circuit from the outside environment 12 comprises an inlet for the air from the outside environment 12 to be heated, an outlet for the air from the first heat exchanger 10 that has been heated, and a plurality of air supply modules (not shown) from the outside environment 12 fluidly connected to said inlet for the air from the outside environment 12 to be heated and outlet for the air from the outside environment 12 that has been heated. Each air supply module from the outside environment 12 comprises a plurality of air supply module fins from the outside environment 12.

[0065] Heat is transferred by the first heat transfer fluid 6 of each first heat transfer fluid supply module 6 to the walls and to the plurality of fins of the first heat transfer fluid supply module 6, from the latter to the plurality of fins of the external air supply module 12 and from said plurality of fins of the external air supply module 12 to the air from the external environment 12 which circulates in the external air supply modules 12. Advantageously, a fan allows circulation of the air from the external environment 12 through said first heat exchanger 10.

[0066] In this first embodiment, the device 19 also includes a second cooling circuit 24 for cooling the power source 2. The second cooling circuit 24 is closed and intended to contain a second heat transfer fluid 14.

[0067] The second cooling circuit 24 further includes a second heat exchanger 26 for exchanging heat and cooling between the first heat transfer fluid 6 and the second heat transfer fluid 14. In particular, the second heat exchanger 26 is for example of the OCOC type, for Oil Cooling Oil Cooler in Anglo-Saxon terms, said second heat exchanger 26 being able to be a tube, plate, fin, pico type exchanger, or being able to result from an additive manufacturing process.

[0068] The second heat transfer fluid 14 is set in motion, for example by means of a second pump (not shown) of the second cooling circuit 24, in order to force its circulation on the second cooling circuit 24 from the second heat exchanger 26 to the power source 2 and from the power source 2 to the second heat exchanger 26. The second heat transfer fluid 14 exiting the second heat exchanger 26 thus allows the temperature of the power source 2 to be regulated.

[0069] The first heat transfer fluid 6 is, for example, the oil from the main transmission of the aircraft and serves as an intermediate cold source for the cooling of the second heat transfer fluid 14, which is, for example, the oil from the power source 2.

[0070] The first and second heat transfer fluids 6 and 14 may be of different natures.

[0071] In this first embodiment, the second heat exchanger 26 is carried by a part of the aircraft installation; it is equipment external to the power source 2 and the power transmission means 4.

[0072] Optionally, the device 19 includes a dry or wet housing, for example made of aluminum or steel, formed around the power source 2.

[0073] Figure 3 shows a second embodiment of an aircraft propulsion system designed to house a temperature control device 19 for a power source 2. The propulsion system comprises a power transmission means 4 cooled by an ACOC as described in the first embodiment, a power source 2, and a temperature control device 19 for a power source 2 substantially similar to the device 19 of the first embodiment. In this second embodiment, the power source 2 directly drives the power transmission means 4, for example, by means of a drive shaft directly connecting the power source 2 and the power transmission means 4. This proximity between the power source 2 and the power transmission means 4 is particularly advantageous in highly integrated engine system architectures.

[0074] Advantageously, the device 19 includes a housing (not shown), formed around the power source 2, which serves to recover the second heat transfer fluid 14 used to cool and / or lubricate the power source 2. Furthermore, the housing provides the interface between the power source 2 and the power transmission means 4, thus allowing the second heat exchanger 26 to be integrated into the housing. In particular, the housing is intended to provide the interface between the first cooling circuit 22 and the second cooling circuit 24. The second heat exchanger 26 allows the second heat transfer fluid 14 to be cooled using the first heat transfer fluid 6.

[0075] Figure 4 shows a propulsion system of an aircraft intended to house a temperature control device 19 for a power source 2 according to a third embodiment. The propulsion system includes a power transmission means 4 cooled by an ACOC in the manner described in the first embodiment, a power source 2 and a temperature control device 19 of a power source 2 substantially similar to the device 19 of the first embodiment.

[0076] Advantageously, the device 19 includes a housing (not shown), formed around the power source 2 allowing the second heat exchanger 26 to be integrated into said housing so that the heat transfer between the first heat transfer fluid 6 and the second heat transfer fluid 14 takes place inside the housing.

[0077] In the third embodiment, the second heat transfer fluid 14 circulates from the power source 2 to the second heat exchanger 26 and from the second heat exchanger 26 to the power source 2 so that the second heat transfer fluid 14 regulates the temperature of the power source 2. In addition, the second heat exchanger 26 allows the second heat transfer fluid 14 to be cooled by the first heat transfer fluid 6.

[0078] Figure 5 shows a propulsion assembly of an aircraft intended to house a temperature control device 19 for a power source 2 according to a fourth embodiment. The propulsion assembly comprises a power transmission means 4 cooled by an ACOC in the manner described in the first embodiment, a power source 2, and a temperature control device 19 for a power source 2 substantially similar to the device 19 of the first embodiment.

[0079] In the fourth embodiment, the second heat exchanger 26 is supported by the power source 2. Furthermore, a section of the second cooling circuit 24, allowing the flow and return of the second heat transfer fluid 14 between the power source 2 and the second heat exchanger 26, is shorter compared to the first embodiment due to the proximity between the second heat exchanger 26 and the power source 2. Optionally, the first cooling circuit 22 can also be shorter compared to the first embodiment due to the proximity between the second heat exchanger 26 and the power transmission means 4. The second heat exchanger 26 allows the second heat transfer fluid 14 to be cooled using the first heat transfer fluid 6.

[0080] Figure 6 shows a propulsion assembly of an aircraft intended to house a temperature control device 19 for a power source 2 according to a fifth embodiment. The propulsion assembly comprises a power transmission means 4 cooled by an ACOC in the manner described in the first embodiment, a power source 2, and a temperature control device 19 for a power source 2 substantially similar to the device 19 of the first embodiment.

[0081] In this fifth embodiment, the power transmission means 4 includes an electric motor. Advantageously, the electric motor drives a thruster 28 which provides lift and / or propulsion to the aircraft.

[0082] The propulsion assembly includes an electric generator 30 and a power transmission shaft 32 connecting the power source 2 to the electric generator 30. In addition, the power source 2 transmits motion to the power transmission shaft 32 and the power transmission shaft 32 transmits this motion to the electric generator 30. Advantageously, the electric generator 30 supplies the electric motor of the power transmission means 4.

[0083] Optionally, the first cooling circuit 22 is a lubrication and / or bearing cooling oil circuit for the electric motor. Advantageously, the first cooling circuit 22 is configured such that the first heat transfer fluid 6 flows from the electric motor to the first heat exchanger 10, then from the first heat exchanger 10 to the second heat exchanger 26, then from the second heat exchanger 26 back to the first heat exchanger 10, and finally from the first heat exchanger 10 back to the electric motor. Furthermore, the second heat exchanger 26 allows the first heat transfer fluid 6 to be used to cool the second heat transfer fluid 14.

[0084] Furthermore, in this embodiment, there is no mechanical link between the power source 2 and the power transmission means 4.

[0085] In an alternative embodiment of the fifth embodiment, the propulsion assembly includes a common wall separating the first heat exchanger 10 and the second heat exchanger 26. Said wall is provided with passages allowing the circulation of the first heat transfer fluid 6 from the first heat exchanger 10 to the second heat exchanger 26 and from the second heat exchanger 26 to the first heat exchanger 10. Optionally, said wall is provided with passages allowing the circulation of the second heat transfer fluid 14 from the second heat exchanger 26 to the first heat exchanger 10 and from the first heat exchanger 10 to the second heat exchanger 26.This variant embodiment of the fifth embodiment eliminates the need for pipes connecting the first heat exchanger 10 to the second heat exchanger 26, thereby reducing the mass of the propulsion assembly and minimizing the risk of heat transfer fluid leaks at the cooling circuit pipe connections.

[0086] In general, the present invention relates to any propulsion assembly of an aircraft comprising a power source 2 and a power transmission means 4 using a first heat transfer fluid in thermal contact with the power transmission means 4 as an intermediate cold source to cool a second heat transfer fluid in thermal contact with the power source 2.

[0087] Figure 7 also shows the steps of a regulation process of temperature of a power source 3 of an aircraft using the control device 19.

[0088] Firstly, a step 34 is carried out of putting the first heat transfer fluid 6 into circulation in the first cooling circuit 22.

[0089] Then, a heat transfer step 36 from the first heat transfer fluid 6 to the external environment 12 is carried out so as to cool the first heat transfer fluid 6. The heat transfer steps 36 and following occur naturally when a fluid is brought into proximity with an organ to be cooled or heated.

[0090] In the next step 38, heat is transferred from the power transmission means 4 to the first heat transfer fluid 6 so as to cool the power transmission means 4.

[0091] In a second step, or preferably at the same time as step 34, a step 40 is implemented of putting the second heat transfer fluid 14 into circulation in the second cooling circuit 24 and then a step 42 of heat transfer from the second heat transfer fluid 14 to the first heat transfer fluid 6 in order to cool the second heat transfer fluid 14.

[0092] The heat is finally transferred from the power source 2 to the second heat transfer fluid 14 so as to cool the power source 2 (step 44).

Claims

Demands

1. A device (19) for regulating the temperature of a power source (2) of an aircraft, comprising a first cooling circuit (22) of a power transmission means (4) of the aircraft, the first cooling circuit (22) being intended to contain a first heat transfer fluid (6) and comprising a first heat exchanger (10) between said first heat transfer fluid (6) and an external medium (12) to the first cooling circuit (22), characterized in that it further comprises a second cooling circuit (24) of the power source (2) intended to contain a second heat transfer fluid (14) and comprising a second heat exchanger (26) between the first heat transfer fluid (6) and the second heat transfer fluid (14), the first heat transfer fluid (6) serving as a cold source for the second heat transfer fluid (14), the device (19) comprising a housing intended to be formed around the power source (2),the casing comprising an interface with the first cooling circuit (22) and allowing the integration of the second heat exchanger (26) into said casing so as to allow heat exchange between the first heat transfer fluid (6) and the second heat transfer fluid (14). .,

2. Device (19) according to claim 1, wherein the first cooling circuit (22) comprises a closed circuit so as to circulate the first heat transfer fluid (6) from the first heat exchanger (10) to the power transmission means (4), and from the power transmission means (4) to the first heat exchanger (10).

3. Device (19) according to any one of claims 1 and 2, wherein the second cooling circuit (24) comprises a closed circuit so as to circulate the second heat transfer fluid (14) from the second heat exchanger (26) to the power source (2), and from the power source (2) to the second heat exchanger (26).

4. Device (19) according to any one of claims 1 to 3, wherein the second heat exchanger (26) allows heat exchange between the first heat transfer fluid (6) flowing from the power transmission means (4) and the second heat transfer fluid (14) flowing towards the power source (2).

5. Device (19) according to any one of claims 1 to 4, wherein the first cooling circuit (22) passes through the second heat exchanger (26) in which the second heat transfer fluid (14) circulates, so that the first heat transfer fluid (6) cools the second heat transfer fluid (14).

6. Aircraft propulsion assembly characterized in that it comprises a power source (2), a power transmission means (4) and a control device (19) according to any one of claims 1 to 5.

7. Propulsion assembly according to claim 6, wherein the power source (2) comprises a heat engine and / or an electric motor and wherein the power transmission means (4) comprises a transmission box.

8. Aircraft, characterized in that it comprises a power source (2), a power transmission means (4) and a device (19) according to any one of claims 1 to 5 and / or a propulsion assembly according to any one of claims 6 and 7.

9. A method for regulating the temperature of a power source (2) of an aircraft by means of a device (19) according to any one of claims 1 to 5, characterized in that it comprises the following steps: - Circulating the first heat transfer fluid (6) in the first cooling circuit (22); - Transferring heat from the first heat transfer fluid (6) to the external environment (12) so as to cool the first heat transfer fluid (6); - Transferring heat from the power transmission means (4) to the first heat transfer fluid (6) so as to cool the power transmission means (4); - Circulating the second heat transfer fluid (14) in the second cooling circuit (24); - Transferring heat from the second heat transfer fluid (14) to the first heat transfer fluid (6) so as to cool the second heat transfer fluid (14);

10. - Heat transfer from the power source (2) to the second heat transfer fluid (14) so ​​as to cool the power source (2).

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