AIR COMPRESSION DEVICE FOR AN AIRCRAFT

Abstract

The invention relates to an air compression device (401) for an aircraft. The described device comprises an electric compressor (403) configured to generate, at a first air outlet (405), via a first compression wheel (407) mounted on a first shaft (409) driven by an electric motor (411), a first flow of compressed air (413), and a turbocharger (415) comprising a second compression wheel (417) and a turbine (419) mounted on a second shaft (421), and configured to generate, at a second air outlet, via the second compression wheel (417), a second flow of compressed air (423). Furthermore, the turbocharger (415) is independent and separate from the electric compressor (403), and the second compressor wheel (417) is supplied by the first compressed air stream (413) from the first air outlet (405) of the electric compressor (403). (See Figure 4 for abbreviations.)

Description

Title of the invention: AIR COMPRESSION DEVICE FOR AN AIRCRAFT Technical field of the invention

[0001] The invention relates to the field of systems used to compress air in a vehicle and relates, in particular, to an air compression device for an aircraft. Technical background

[0002] Some current aircraft are said to be "bleedless", that is to say that they do not use an air bleed, and more particularly a bleed of compressed and heated air produced by a gas turbine, to supply aircraft systems such as the cabin pressurization system for example. This type of operation for an aircraft makes it possible in particular to save fuel by reducing the mass of the aircraft.

[0003] In this context, it is known to use an electric compressor to produce the compressed air which is used in the aircraft systems and which no longer comes from an engine air bleed.

[0004] By way of example, [Fig.l] schematically illustrates the operation of an air compression device 101 which is an electric compressor. In this electric compressor, the air flow 103, admitted at the air inlet 105, is compressed by the compression wheel 107. We speak of an electric compressor insofar as the compression wheel 107 is mounted on a shaft 109 which is integral with a rotor 119 of an electric motor 111.

[0005] In the example shown, the compressed air flow 113, emitted at the air outlet 115, supplies a system 117 of an aircraft (not shown) which requires compressed air for its operation.

[0006] As an example, a more detailed description of such an electric compressor can be found in patent FR-B1-3 045 111 in particular.

[0007] Typically, for an electric compressor such as this, the compression ratio (i.e. the ratio of the air pressure at the outlet of the device to the air pressure at the inlet of the device) achievable is, for example, 3.5 at most.

[0008] However, to achieve such a value, the electric compressor must consume, for example, a power of approximately 8 kilowatts and the temperature of the air circulating through the electric compressor which achieves such a compression ratio, goes from ambient temperature (approximately 20°C) at the air inlet to a temperature high (for example around 300°C) at the air outlet of the electric compressor due to the compression ratio.

[0009] As a result, such an electric compressor may require the use of a dedicated cooling system, i.e. an active cooling system additional to the electric compressor, which supplies a gas or a liquid to the electric compressor suitable for cooling its components and in particular the motor and the power electronics to prevent its degradation.

[0010] In addition, some air compression devices also use a turbine to recover energy from the air leaving the aircraft system powered by the compressed air flow and thus improve the efficiency of the device.

[0011] [Fig.2] illustrates an example of such an air compression device 201 in which the air flow 203, admitted at the air inlet 205, is compressed by the compression wheel 207. The compression wheel 207 is driven by an electric motor 219 and it is configured to generate a compressed air flow 209a at the air outlet 211 of the air compression device 201.

[0012] Furthermore, after having supplied a system 213 of the aircraft, the compressed air flow 209b, at the outlet of the system, is recovered by a turbine 215 which is integrated into the air compression device 201. The compression wheel 207 and the turbine 215 are mounted on the same shaft 217 of the air compression device 201. And the turbine makes it possible to recover part of the energy used to supply a system of an aircraft.

[0013] Due to the improvement in efficiency obtained through the use of the turbine, such a device makes it possible to obtain a higher compression ratio for the same power consumed.

[0014] However, in this configuration also, the temperature of the compressed air flow generated at the outlet is very high, for example around 250°C, and may therefore require the use of a dedicated cooling system to cool certain components of the air compression device.

[0015] Figures 3A and 3B show air compression devices called com two-stage compressors with air cooling and water cooling respectively. Such a device is also called a motor-turbocharger. Some elements are only visible in one of the two figures and elements having the same function have the same reference in the figures.

[0016] For the air compression devices 301 and 303, the air flow admitted at the air inlet 305 is compressed by the compression wheel 307. The compressed air flow 309a exits through the air outlet 311 and supplies compressed air to a system 313 of an aircraft (not shown).

[0017] Furthermore, the compressed air flow 309b at the outlet of the system 313 is recovered at level of an air inlet 311 of a turbine 313.

[0018] The compression wheel 307 and the turbine 313 are mounted on the same shaft secured to a permanent magnet rotor 315 which is driven in rotation by the magnetic field generated by a stator 317. The stator 317 and the permanent magnet rotor 315 form an electric motor 321.

[0019] Finally, the air compression devices 301 and 303 both integrate at least one inlet / outlet 319 intended to allow the admission / ejection of air or cooling water, for example at ambient temperature, into the device.

[0020] Indeed, the air compression devices described require the use of a dedicated cooling system to avoid the deterioration of certain components due to temperatures that are too high to be supported by said components.

[0021] A possible variant of such an air compression device, making it possible both to maintain high efficiency and to achieve high compression ratios as well, consists of integrating a turbine into a so-called multi-stage electric compressor, i.e. an electric compressor integrating several compression wheels in series. In particular, the addition of a turbine leads to significant technical integration difficulties since the production of a shaft with three stages is particularly complex.

[0022] In all the solutions described above, the known air compression devices involve the use of dedicated cooling systems since they aim for high compression ratios (for example ratios greater than or equal to 3.5) and limited power consumption (less than or equal to 3 kilowatts). Summary of the invention

[0023] The present invention provides a solution to these drawbacks.

[0024] To this end, according to a first aspect, the invention relates to an air compression device for an aircraft, comprising:

[0025] - an electric compressor configured to generate, at a first output of air, by means of a first compression wheel mounted on a first shaft driven by an electric motor, a first flow of compressed air, and

[0026] - a turbocharger comprising a second compression wheel and a turbine mounted on a second shaft, and being configured to generate, at a second air outlet, via the second compression wheel, a second flow of compressed air,

[0027] said air compression device being characterized in that the turbocharger is independent and separate from the electric compressor and in that the second compression wheel is supplied by the first flow of compressed air coming from the first air outlet of the electric compressor,

[0028] and in that the second flow of compressed air is intended to supply at least one system of the aircraft included among a cabin pressurization system and a tank inerting system.

[0029] The air compression device according to the invention may comprise one or more of the following features, taken in isolation from one another or in combination with one another:

[0030] - the electric compressor is single-stage.

[0031] - the electric compressor does not have a dedicated cooling system.

[0032] - the turbocharger is mechanical.

[0033] - the turbocharger is adapted to withstand high temperatures, preferably up to 600°C.

[0034] - the electric compressor is configured to achieve a first compression rate determined pressure.

[0035] - the turbocharger is configured to achieve a second compression ratio determined.

[0036] The invention also relates, according to a second aspect, to an aircraft comprising an air compression device according to the first aspect.

[0037] Optionally, the aircraft may include elements cooled by an air flow from the turbocharger turbine. Brief description of the figures

[0038] The present invention will be better understood and other details, characteristics and advantages of the present invention will appear more clearly on reading the description of a non-limiting example which follows, with reference to the appended drawings in which:

[0039] [Fig-1] [Fig.l] is a schematic representation of an embodiment of a air compression device for an aircraft according to the prior art;

[0040] [Fig.2] [Fig.2] is a schematic representation of an embodiment of a air compression device for an aircraft according to the prior art;

[0041] [Fig.3A] [Fig.3A] is a partially sectioned perspective view of an embodiment of an air compression device for an aircraft according to the prior art;

[0042] [Fig.3B] [Fig.3B] is a perspective view of an embodiment of an air compression device for an aircraft according to the prior art; and,

[0043] [Fig.4] [Fig.4] is a schematic representation of an embodiment of a air compression device for an aircraft according to the invention.

[0044] Elements having the same functions in the different embodiments have the same references in the figures. Detailed description of the invention

[0045] With reference to [Fig.4], we will now describe an embodiment of an air compression device according to the invention. The air compression device described is an air compression device for an aircraft, however the architecture of this air compression device can be used for other types of vehicles such as for example an automobile.

[0046] The air compression device 401 comprises an electric compressor 403. An air flow 427 is admitted into the electric compressor, at an air inlet 435, then is compressed by a compression wheel 407 of the electric compressor 403. The compressor is said to be electric insofar as the compression wheel 407 is mounted on a shaft 409 which is integral with a rotor of an electric motor 411.

[0047] A flow of compressed air 413 is therefore generated by the electric compressor 403 at the air outlet 405, via the compression wheel 407.

[0048] The air compression device 401 also comprises a turbocharger 415 which comprises a compression wheel 417 and a turbine 419 which are both mounted on a same shaft 421.

[0049] In the example shown, the turbocharger 415 is only represented schematically by the compression wheel 417, the shaft 421 and the turbine 419. Those skilled in the art will appreciate that the invention applies to any type of turbocharger.

[0050] Furthermore, in the example shown, the turbocharger 415 is said to be mechanical, that is to say that the compression wheel 417 and the turbine 419 are only driven in rotation by mechanical energy without using electrical energy or another type of energy.

[0051] The turbocharger 415 is configured to generate, at an air outlet (not shown), via the compression wheel 417, a flow of compressed air 423a.

[0052] In the example shown, it is this compressed air flow 423a which is used to supply a system of an aircraft with compressed air. The value of the air pressure of the compressed air flow 423a may be, in a non-limiting example, approximately 2850 hectopascals while the value of the pressure of the compressed air flow 413 is approximately 1400 hectopascals and that of the air flow 427 at the inlet is approximately 800 hectopascals.

[0053] Furthermore, an aircraft system powered by this flow may be, for example, a cabin pressurization system, a tank inerting system or even a combustion cell.

[0054] In the air compression device 401 the turbocharger 415 is independent and separate from the electric compressor 403, that is to say that no element of the turbocharger 415 is integrated into the electric compressor 403. The shaft 409 is distinct from the shaft 421 and the turbocharger is located outside an external casing 425 of the electric compressor 403.

[0055] Furthermore, the compression wheel 417 is powered by the compressed air flow 413 which comes from the air outlet 405 of the electric compressor 403.

[0056] In addition, the use of the turbocharger makes it possible to recover part of the energy used to power the system(s) of the aircraft. Thus, in the example shown, the compressed air flow 423b at the outlet of the system 429 is used to power the turbine 419 of the turbocharger 415.

[0057] The fact that, on the one hand, the electric compressor 403 and the turbocharger 415 are separate and, on the other hand, the turbocharger 415 uses as input the compressed air flow 423a coming from the electric compressor 403 makes it possible to achieve a high compression ratio (for example greater than 3.5) for the air compression device 401 by decomposing this compression ratio between the electric compressor 403 and the turbocharger 415.

[0058] The electric compressor 403 can be used as a “pre-compressor” configured to achieve a moderate compression ratio, such as, for example, but not limited to, a compression ratio between 1.4 and 2.1.

[0059] Whereas the turbocharger 415 may "supplement" the compression ratio by being configured to also achieve a moderate compression ratio as well, such as, for example, but not limited to, a compression ratio of between 1.4 and 2.1.

[0060] Thus, the air compression device 401 makes it possible to achieve a high compression ratio, such as, for example, but not limited to, a compression ratio equal to 3.3 or a compression ratio greater than 3.5.

[0061] Furthermore, such a compression ratio can be achieved by using a single-stage electric compressor, i.e. an electric compressor comprising only one compression wheel.

[0062] Similarly, the electric compressor used, particularly since its use is limited to moderate compression ratios, does not necessarily require a dedicated cooling system to avoid deterioration of its components. In other words, the electric compressor can be self-cooled, i.e., no additional active system is required to provide a gas or liquid used for cooling its components.

[0063] In the non-limiting example shown, the temperature of the air flow at the inlet of the air compression device 401 is equal to 20°C while the temperature of the compressed air flow 413 is equal to 115°C and that of the compressed air flow 423 is equal to 240°C.

[0064] Generally speaking, the turbocharger included in the air compression device according to the invention can be adapted to withstand high temperatures incompatible with an electric motor (i.e. which would be likely to damage it) such as temperatures up to 600°C.

[0065] Thus, the electric compressor is only exposed to temperatures that are not likely to damage these components and the turbocharger, which is more robust at high temperatures, is also not subjected to temperatures that are likely to damage it.

[0066] Finally, the cold air flow 433 (at ambient temperature or lower) generated by the turbine 419 of the turbocharger 415 can be used to cool elements of the aircraft in which the air compression device is integrated.

[0067] In conclusion, the air compression device according to the invention makes it possible to obtain high efficiency and a high compression ratio without necessarily having to resort to the use of a dedicated cooling system.

[0068] This therefore represents both a gain in weight and fuel consumption for the aircraft into which the device is integrated and a gain in performance of the device as well as a simplification of its architecture.

Claims

Claims

1. Air compression device (401) for an aircraft, comprising: - an electric compressor (403) configured to generate, at a first air outlet (405), via a first compression wheel (407) mounted on a first shaft (409) driven by an electric motor (411), a first compressed air flow (413), and - a turbocharger (415) comprising a second compression wheel (417) and a turbine (419) mounted on a second shaft (421), and being configured to generate, at a second air outlet, via the second compression wheel (417), a second compressed air flow (423), said air compression device (401) being characterized in that the turbocharger (415) is independent and separate from the electric compressor (403) and in that the second compression wheel (417) is powered by the first flow of compressed air (413) from the first air outlet (405) of the electric compressor (403),and in that the second compressed air flow (423) is intended to supply at least one system (429) of the aircraft included among a cabin pressurization system and a tank inerting system.,

2. An air compression device (401) according to any preceding claim, wherein the electric compressor (403) is single-stage.

3. An air compression device (401) according to any preceding claim, wherein the electric compressor (403) lacks a dedicated cooling system.

4. An air compression device (401) according to any preceding claim, wherein the turbocharger (415) is mechanical.

5. An air compression device (401) according to any preceding claim, wherein the turbocharger (415) is adapted to withstand high temperatures, preferably up to 600°C.

6. An air compression device (401) according to any preceding claim, wherein the electric compressor (403) is configured to achieve a first determined compression ratio.

7. An air compression device (401) according to any preceding claim, wherein the turbocharger (415) is configured to achieve a second determined compression ratio.

8. An aircraft comprising an air compression device (401) according to any one of the preceding claims.

9. Aircraft according to claim 9, said aircraft comprising elements cooled by an air flow from the turbine (419) of the turbocharger (415).

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