Non-propulsive turbomachine for a fuel conditioning system to supply an aircraft propulsion turboshaft engine and associated method

Abstract

A non-propulsive turbomachine (2) for an aircraft (M) fuel conditioning system (Q) comprising: a first compressor (21), a combustion chamber (23) supplied by a first airflow (A1) flowing in a general supply channel (30) connected to the first compressor (21), a second compressor (22) connected to the general supply channel (30) by a first sampling channel (31), so as to be supplied with a second airflow (A2) from the first compressor (21), and to a cabin air conditioning device (6), a single gas turbine (24) connected to both the first compressor (21) and the second compressor (22) by a single turbomachine shaft (25), a second sampling channel (33) connecting the general supply channel (30) and the cabin air conditioning device (6), and at least one sampling valve (4),mounted on the first sampling channel (31) and configured to allow or prevent the circulation of the second airflow (A2) in the sampling channel (31). Abstract figure: Figure 3,

Description

Title of the invention: Non-propulsive turbomachine for a fuel conditioning system to supply an aircraft propulsion turboshaft engine and associated method. Technical field

[0001] The present invention relates to the field of aircraft comprising propulsion systems powered by fuel stored in a cryogenic tank.

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

[0003] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

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

[0005] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0006] To this end, the invention is the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft. For this purpose, The invention relates to propulsion systems powered by fuel stored in a cryogenic tank.

[0007] It is known to store fuel, particularly hydrogen, in liquid form to limit the size and mass of aircraft tanks. For example, fuel is stored at a temperature of approximately -253 to -251°C (20 to 22 Kelvins) in a cryogenic tank on the aircraft.

[0008] In order to be injected into the combustion chamber of a turbomachine for example, the fuel must be conditioned, i.e. pressurized and heated, in order to allow optimal combustion.

[0009] In practice, the heating stage is energy-intensive and requires extracting heat from hot sources. Among the various technologies for heating liquid fuel, with reference to [Fig. 1], it is known to generate a flow of heating gas AC by means of a non-propulsive turbomachine 102 supplied, on the one hand, by fuel Q from a cryogenic tank R and, on the other hand, by an airflow A. A non-propulsive turbomachine is a turbomachine that does not contribute to the thrust of the aircraft. To this end, the non-propulsive turbomachine 102 comprises, successively, along a direction of airflow A, a compressor 121 comprising one or more stages, a combustion chamber 122, and a turbine 123 comprising one or more stages.During operation of the non-propulsive turbomachine 102, the compressor 121 compresses an incoming air stream A, which mixes with the fuel stream Q in the combustion chamber 122 to generate the heating gas stream AC. This generates mechanical energy via the turbine 123, which can drive the compressor 121 via a mechanical shaft 124. A heat exchanger 101 transfers heat from the heating gas stream AC to the liquid fuel stream Q, thus converting it to a gaseous state. The fuel stream Q is then ready for use in a combustion chamber CC of the aircraft engine M.

[0010] The non-propulsive turbomachine 102 is also connected to an electrical generator 103 configured to supply an electrical network of the aircraft. The non-propulsive turbomachine 102 thus generates electrical energy to power equipment of the aircraft.

[0011] In a known architecture, in order to optimize the aircraft's mass and limit the number of components, the non-propulsive turbomachine 102 is also connected to a cabin air conditioning system 104 (known to those skilled in the art by its English acronym "ECS" for "Environment Control System") to supply it with pressurized air. In practice, a pressurized airflow Ap is taken from the outlet of the compressor 121 of the non-propulsive turbomachine 102 and supplies the air conditioning system 104. The non-propulsive turbomachine 102 thus advantageously generates a flow of heating gas AC to heat the fuel Q, to generate electrical power to power various equipment and to provide a pressurized airflow Ap to the cabin air conditioning device 104.

[0012] However, to fulfill these three functions, such a non-propulsive turbomachine 102, generally with two shafts, is complex and significantly increases the mass and size of the conditioning system in which it is mounted.

[0013] In particular, to supply the air conditioning unit 104, the compressed air flow Ap must have a predefined pressure. Therefore, in this design, the compressor 121 is sized to generate a compressed air flow Ap at the expected pressure. In practice, the incoming air pressure varies depending on the aircraft's altitude, being higher at low altitudes than at high altitudes. Since the compressor 121 is sized to ensure that the expected pressure value is achieved regardless of the aircraft's altitude, it is designed at high altitudes, resulting in over-compression of the airflow at low altitudes. Such over-compression can lead to compressor surge, which can damage the non-propulsive turbomachine.

[0014] An immediate solution to reduce the risk of pumping would be to reduce the rotational speed of the mechanical shaft. However, to heat the fuel flow and / or power the electrical equipment, the non-propulsive turbomachine must generate a calibrated flow of heating gas, which requires a predetermined rotational speed. In other words, prior art non-propulsive turbomachines do not allow for an acceptable compromise to optimally fulfill all the aforementioned functions.

[0015] The invention thus aims to eliminate at least some of these drawbacks by providing a non-propulsive turbomachine that can simultaneously supply a fuel heating gas flow, electrical power to supply various aircraft equipment, and a pressurized air flow to supply a cabin air conditioning system, while having an optimized architecture. The invention particularly relates to a non-propulsive turbomachine whose operation is optimal and simplified, regardless of the air pressure entering the compression stage. PRESENTATION OF THE INVENTION

[0016] The invention relates to a non-propulsive turbomachine for a fuel conditioning system configured to supply an aircraft turboshaft engine with fuel from a cryogenic tank, the non-propulsive turbomachine comprising: • a first compressor configured to be powered by an ambient airflow and to generate a pressurized airflow, • a combustion chamber configured to be supplied, on the one hand, by a fuel flow from the cryogenic tank, and, on the other hand, by a first air flow circulating in a general supply duct connected to the first compressor, the combustion chamber being configured to exhaust a heat-laden exhaust gas flow, • a second compressor, on the one hand connected to the general supply channel by a first intake channel so as to be supplied with a second airflow from the first compressor, and on the other hand, configured to be connected to a cabin air conditioning device by a circulation channel, so as to supply it with a third airflow, • a single gas turbine connected to both the first and second compressors by a single turbomachine shaft, the gas turbine being configured to be driven in rotation by the exhaust gas flow from the combustion chamber and to simultaneously drive the first and second compressors, • a second sampling channel connected to the main supply channel and configured to be connected to the cabin air conditioning unit, so as to supply it with a fourth airflow from the first compressor, and • at least one sampling valve, mounted on the first sampling channel between the main supply channel and the second compressor, the sampling valve being configured to allow or prohibit the circulation of the second airflow in the sampling channel so as to supply the cabin air conditioning device with the third airflow and / or the fourth airflow.

[0017] The non-propulsive turbomachine according to the invention supplies the aircraft's cabin air conditioning system regardless of the pressure of the pressurized airflow exiting the first compressor, without risk of damage. The bypass valve prevents airflow from entering the second compressor when the incoming airflow pressure is too high, thus avoiding any risk of over-compression and therefore over-pumping. The long-term reliability of the non-propulsive turbomachine is advantageously ensured.

[0018] Thus, the airflow supplying the cabin air conditioning system is at the expected pressure both at low altitude, being supplied by the first compressor, and at high altitude, being supplied by the second compressor, itself supplied by the first compressor. The airflow supplying the second The compressor being derived from the first compressor, the latter is compressed twice successively, which also allows limiting the sizing of the second compressor, limiting the mass and size of the non-propulsive turbomachine.

[0019] According to a preferred aspect, the non-propulsive turbomachine comprises: • a first regulating valve mounted on the circulation channel and configured to at least allow or prohibit the circulation of the third airflow from the second compressor to the cabin air conditioning unit, and • a second control valve mounted on the second sampling channel and configured to at least allow or prohibit the circulation of the fourth airflow from the first compressor to the cabin air conditioning device.

[0020] The control valves allow the air supply to the cabin air conditioning system to be controlled by permitting or preventing the flow of one of the third or fourth air streams and allowing the other of the third or fourth air streams. Such valves ensure that the cabin air conditioning system is supplied with an airflow at the expected pressure.

[0021] In one embodiment, the non-propulsive turbomachine includes a relief valve mounted on the second intake channel. The relief valve allows the pressure of the fourth air stream to be lowered before it is introduced into the cabin air conditioning system, for example, when the pressure of the fourth air stream is too high.

[0022] According to one aspect, the non-propulsive turbomachine comprises a single external air inlet, this single air inlet being connected to the first compressor. The second compressor is thus supplied solely by air from the first compressor, which allows for simpler sizing.

[0023] Preferably, the non-propulsive turbomachine includes a control system for the scavenging valve. The control system comprises a device for measuring the pressure at the outlet of the first compressor and / or the aircraft altitude, and a computer connected to the measuring device and the scavenging valve and configured to control the scavenging valve based on the measured pressure and / or the determined altitude. Thus, when the pressure at the outlet of the first compressor is too high, the scavenging valve is advantageously controlled to shut off the circulation of the second airflow and prevent any risk of the second compressor over-surge.

[0024] In one embodiment, the measuring device is a pressure sensor mounted directly at the outlet of the first compressor, the computer being configured to receive a measurement from the measuring device and to control the sampling valve: • in the closed position when the pressure measured by the measuring device is greater than or equal to a predetermined pressure threshold, and • in the open position when the pressure measured by the measuring device is below the predetermined pressure threshold.

[0025] This allows, by adding a simple sensor, for the sampling valve to be controlled directly based on the pressure of the airflow exiting the first compressor, thus preventing any risk of over-compression that could lead to a risk of surging. Similarly, when the aircraft is at a higher latitude, the pressure of the incoming airflow being lower, the computer automatically opens the sampling valve to switch to the second compressor, so as to continue supplying the cabin air conditioning system with airflow at the expected pressure.

[0026] In an alternative embodiment, the measuring device is an altimeter, the computer being configured to receive a measurement from the measuring device and to control the sampling valve: • in the closed position when the altitude determined by the measuring device is below a predetermined altitude threshold, so as to supply the cabin air conditioning system with the fourth airflow from the first compressor, and • in the open position when the altitude determined by the measuring device is greater than or equal to the predetermined altitude threshold, so as to supply the cabin air conditioning device with the third airflow from the second compressor.

[0027] This allows the bleed valve to be controlled directly according to the aircraft's altitude, which affects the pressure of the air entering the first compressor and therefore the pressure of the airflow entering the second compressor. Thus, the non-propulsive turbomachine supplies the cabin air conditioning system with either the third or fourth airflow, depending on the aircraft's altitude. Preferably, the measuring device is directly integrated with the altimeter mounted in the aircraft's cockpit and used by the pilots, thereby eliminating the need for additional equipment.

[0028] According to a preferred aspect, the non-propulsive turbomachine includes a heat exchanger configured to heat the fuel stream using calories transferred from the exhaust gas stream of the gas turbine. The heat exchanger allows the fuel stream to be converted into a gaseous state so that it can be injected. in the combustion chamber of the propulsion turbomachine. The non-propulsive turbomachine then makes it possible both to generate a flow of exhaust gas charged with calories to heat the fuel flow from the cryogenic tank and to supply the cabin air conditioning system, which limits the size of the air conditioning system in which the non-propulsive turbomachine is mounted.

[0029] Preferably, the non-propulsive turbomachine includes an electric generator connected to the turbomachine shaft and configured to generate electrical power to supply the aircraft's electrical system. The non-propulsive turbomachine thus fulfills a triple function: supplying compressed air to the cabin air conditioning system, generating an exhaust gas flow to preheat the fuel flow, and generating electrical power, which contributes to the aircraft's decarbonization.

[0030] In one embodiment, the non-propulsive turbomachine includes a clutch device mounted on the turbomachine shaft and configured to disengage the second compressor, so as to drive only the first compressor in rotation by the gas turbine. Thus, when the bleed valve is closed and the second compressor is not supplied, the clutch device prevents the mechanical energy generated by the gas turbine from being used unnecessarily and wastefully to drive the second compressor. The energy not used to drive the second compressor can advantageously be used for the operation of other aircraft equipment, for example, in the electric generator.

[0031] The invention also relates to a fuel conditioning system configured to supply at least one aircraft propulsion turboshaft engine, the conditioning system comprising: • a cryogenic reservoir, • a fuel circuit connected to the cryogenic tank and configured to be connected to the propulsion turboshaft engine, a fuel flow circulating in the fuel circuit, and • a non-propulsive turbomachine as described above, • the cryogenic tank being configured to supply both the propulsive turbomachine and the combustion chamber of the non-propulsive turbomachine.

[0032] According to one aspect, the heat exchanger is mounted on the fuel circuit so as to heat the fuel stream from the cryogenic tank. The fuel stream is thus heated by the heat transferred from the exhaust gas stream of the non-propulsive turbomachine.

[0033] In one embodiment, the heat exchanger is configured to heat the fuel stream directly from the exhaust gas stream.

[0034] Alternatively, the heat exchanger is configured to heat the fuel stream indirectly from the exhaust gas stream, via a heat transfer fluid.

[0035] The invention also relates to an aircraft comprising at least one propulsion turboshaft engine and a conditioning system as described above, the fuel circulating in the fuel circuit supplying the propulsion turboshaft engine.

[0036] The invention further relates to a method of operating the non-propulsive turbomachine as described above, the sampling valve being initially in a closed position, the circulation of the second airflow in the first sampling channel being prohibited, the method comprising the steps of: • circulate an ambient airflow through the first compressor, with the cabin air conditioning system being supplied by the fourth airflow from the first compressor, and • when the ambient airflow pressure is below a predetermined pressure threshold, control the sampling valve so as to allow the circulation of the second airflow in the first sampling channel and supply the second compressor, so as to supply the cabin air conditioning device with the third airflow.

[0037] Finally, the invention relates to a method of operating the non-propulsive turbomachine as described above, the sampling valve being initially in an open position, the second airflow circulating in the first sampling channel, the method comprising the steps of: • circulate an ambient airflow through the first compressor and then the second compressor, with the cabin air conditioning system being supplied by the third airflow from the second compressor, and • when the ambient airflow pressure is above a predetermined pressure threshold, control the sampling valve so as to prohibit the circulation of the second airflow in the first sampling channel and stop the supply to the second compressor.

[0038] This avoids any risk of over-compression of the airflow in the second compressor, thus avoiding any risk of pumping. PRESENTATION OF THE FIGURES

[0039] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of example. non-exhaustive, in which identical references are given to similar objects.

[0040] Fig. 1 is a schematic representation of a conditioning system comprising a prior art non-propulsive turbomachine.

[0041] The [Fig.2] is a schematic representation of a non-propulsive turbomachine according to a first embodiment of the invention.

[0042] Fig. 3 is a schematic representation of a conditioning system comprising the non-propulsive turbomachine of Fig. 2.

[0043] Fig. 4 is a schematic representation of a conditioning system comprising a non-propulsive turbomachine according to a second embodiment of the invention in a first configuration of use.

[0044] The [Fig.5] is a schematic representation of the conditioning system of the [Fig.4] in a second usage configuration.

[0045] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0046] The invention relates to a non-propulsive turbomachine for an aircraft fuel SC conditioning system.

[0047] With reference to [Fig.2], a fuel conditioning system SC is shown configured to supply one or more aircraft engine(s), in particular, a turboprop engine M, with fuel Q from a cryogenic tank R. It is understood that the aircraft could include more than one cryogenic tank R, the conditioning system SC then being connected to each cryogenic tank R.

[0048] The propulsion turboshaft engine M is configured to provide propulsion for the aircraft (i.e. thrust), in particular, by driving at least one propulsion unit (not shown).

[0049] In this example, the fuel Q is dihydrogen, but the invention applies to other types of fuel, in particular fuels such as methane or liquefied natural gas.

[0050] In practice, the fuel Q is stored in the cryogenic tank R at cryogenic temperatures. For example, the fuel Q is stored in the cryogenic tank R at a temperature of approximately -253 to -251°C (20 to 22 Kelvin). At this temperature, the fuel Q is liquid. In order to be introduced into a combustion chamber of the propulsion turboshaft engine M, the fuel Q must be heated.

[0051] For this purpose, the aircraft includes an SC conditioning system configured to heat and pressurize the Q fuel.

[0052] Still with reference to [Fig.2], the conditioning system SC includes a fuel circuit 1 (represented by closely spaced dashed lines) connected at the inlet to the cryogenic tank R and at the outlet to the combustion chamber of the propulsion turboshaft engine M. In this example, the conditioning system SC also includes a mechanical pump P, preferably high pressure, configured to circulate a fuel flow Q from upstream to downstream in the fuel circuit 1.

[0053] According to one aspect, the SC conditioning system comprises a non-propulsive turbomachine 2 configured to supply a cabin air conditioning system 6 of the aircraft. The non-propulsive turbomachine 2 does not provide thrust for the aircraft and does not have a propulsion component. In practice, the non-propulsive turbomachine 2 is preferably also configured to both supply the energy requirements of the various aircraft equipment (e.g., air conditioning, power supply for flight control or entertainment systems, etc.) and generate a heat-laden gas stream configured to warm the fuel stream Q, as will be described in more detail later.

[0054] With reference to figures 2 and 3, the non-propulsive turbomachine 2 comprises a first compressor 21, a second compressor 22 and a single gas turbine 24 connected together by a single turbomachine shaft 25.

[0055] The first compressor 21 is configured to be supplied by an ambient airflow A, from an external air inlet EA to the aircraft, and to generate a pressurized airflow Ap. Preferably, the non-propulsive turbomachine 2 comprises a single external air inlet EA connected to the first compressor 21. The pressurized airflow Ap is configured at least in part to supply a combustion chamber 23 of the non-propulsive turbomachine 2 via a general supply channel 30, shown in [Fig. 3].

[0056] According to one aspect, the first compressor 21 is sized to supply the combustion chamber 23 with an airflow having a pressure between 0.75 and 4 bar (7.5 x 0.4 and 4 x 0.4 Pa). Preferably, the first compressor 21 has a compression ratio of approximately 3 to 4. In this example, the first compressor 21 comprises a single centrifugal compression stage to enable it to achieve the compression ratio defined above. It is understood that the first compressor 21 could alternatively comprise an assembly of axial compressors / rectifiers.

[0057] According to one aspect of the invention, again with reference to [Fig. 3], the non-propulsive turbomachine 2 comprises a first sampling channel 31 connected to the channel general power supply 30 and configured to power the second compressor 22, as will be described in more detail later.

[0058] The non-propulsive turbomachine 2 also includes a second sampling channel 32 connected to the general supply channel 30 and configured to be connected to the cabin air conditioning device 6 to supply it with an airflow, hereafter fourth airflow A4, compressed in the first compressor 21.

[0059] With further reference to [Fig. 3], the combustion chamber 23 is configured to be supplied, on the one hand, by a fuel flow Q from the cryogenic tank R, and, on the other hand, by a first air flow Al circulating in the general supply channel 30 connecting the first compressor 21 to the combustion chamber 23. As described previously, the first air flow Al corresponds to at least a portion of the pressurized air flow Ap. In practice, the cryogenic tank R supplies the propulsion turbomachine M in parallel with a first fuel flow Q1, and the combustion chamber 23 of the non-propulsive turbomachine 2 with a second fuel flow Q2, as shown in [Fig. 2].

[0060] The combustion chamber 23 is configured to evacuate an exhaust gas flow FE resulting from the combustion of the second fuel flow Q2 with the first air flow Al and charged with calories.

[0061] With reference to [Fig.3], the second compressor 22 is configured to be supplied by a second airflow A2 circulating in the first sampling channel 31 connected to the general supply channel 30. In other words, the second compressor 22 is supplied by an airflow corresponding to a portion of the airflow taken from the pressurized airflow Ap from the first compressor 21.

[0062] The second compressor 22 is also configured to generate a third airflow A3 to supply the aircraft cabin air conditioning unit 6 via a circulation channel 32. In other words, the cabin air conditioning unit 6 can be supplied by an airflow from the first compressor 21 and / or an airflow from the second compressor 22, as will be described in more detail later.

[0063] According to one aspect, the second compressor 22 is sized so that the third airflow A3 has a predetermined pressure to supply the cabin air conditioning unit 6. In this example, the predetermined pressure is between 2 and 4 bar (between 2 x 10⁵ and 4 x 10⁵ Pa). In particular, the second compressor 22 is sized to reach the predetermined pressure value of the third airflow A3 when the pressure of the second airflow A2 at the inlet of the second compressor 22 is on the order of 0.5 x 10⁵ Pa to 10⁵ Pa. Such a pressure corresponds to the pressure of the pressurized airflow Ap at the outlet of the first compressor 21, when it is supplied by an ambient airflow entering through the outside air inlet EA at a pressure of around 0.2 bar (2x04 Pa), corresponding to the atmospheric air pressure when the aircraft is at high altitude, i.e. about 12000 m altitude (40000 feet), corresponding to the average cruising altitude of an aircraft.

[0064] Also, in this example, the second compressor 22 has a compression ratio of approximately 2 to 4, corresponding to the compression ratio required to achieve 2 to 4 bar (2x05 to 4x05 Pa) from an airflow at a pressure of approximately 1 bar (105 Pa). Preferably, the second compressor 22 comprises a single centrifugal compression stage to achieve such a compression ratio. It is understood that the number of stages could be different. Furthermore, the second compressor 22 could alternatively comprise an assembly of axial compressors / straighteners and / or centrifugal compressors.

[0065] In practice, the airflow from the ambient is compressed successively in the first compressor 21 and the second compressor 22 to reach the predetermined pressure in the cabin air conditioning device 6. The second compressor 22 is thus simpler and less bulky.

[0066] As described previously, the non-propulsive turbomachine 2 comprises a single gas turbine 24 connected to both the first compressor 21 and the second compressor 22 by a single turbomachine shaft 25. The gas turbine 24 is configured to be driven in rotation by the exhaust gas flow FE from the combustion chamber 23, and to simultaneously drive in rotation the first compressor 21 and the second compressor 22. Such a non-propulsive turbomachine 2, having a single turbomachine shaft 25 to connect the first compressor 21, the second compressor 22 and the single gas turbine 24, is advantageously simpler, lighter and more compact.

[0067] In a preferred embodiment, with reference to [Fig. 2], the non-propulsive turbomachine 2 includes a heat exchanger 7 configured to preheat the first fuel stream Q1 flowing in the fuel circuit 1 using heat transferred by the exhaust gas stream FE flowing in the gas turbine 24. The exhaust gas stream FE thus vaporizes the first fuel stream Q1 before its injection into the combustion chamber of the propulsion turbomachine M. In one embodiment, the heat exchanger 7 is mounted on the fuel circuit 1. Alternatively (not shown), the conditioning system SC includes a heat transfer fluid circuit mounted between the exhaust gas stream FE and the fuel circuit 1, so as to preheat the fuel stream Q indirectly. This allows the use of a non-propulsive heat transfer fluid reactive and to avoid the risk of contact between an oxidizing fluid and the fuel flow Q in the event of failure of the heat exchanger 7 for example.

[0068] In practice, with reference to [Fig.4], the heat exchanger 7 is preferably configured to heat both the first fuel stream Q1 supplying the combustion chamber of the propulsion turbomachine M and the second fuel stream Q2 supplying the combustion chamber 23 of the non-propulsive turbomachine 2. A single heat exchanger 7 thus allows the fuel stream Q to be brought to a gaseous state before it separates to supply in parallel the propulsion turbomachine M and the non-propulsive turbomachine 2.

[0069] In a preferred embodiment, the non-propulsive turbomachine 2 includes an electric generator G connected to the turbomachine shaft 25 and configured to generate electrical power to supply an aircraft electrical system. The electric generator G can, for example, power the aircraft's equipment when it is on the ground.

[0070] The non-propulsive turbomachine 2 is thus configured both to generate an exhaust gas flow FE to heat the fuel flow Q from the cryogenic tank R, electrical energy via the electric generator G to power an electrical network of the aircraft, and a pressurized air flow to power the cabin air conditioning device 6 of the aircraft.

[0071] In practice, as described above, the cabin air conditioning device 6 can be supplied alternatively or in a complementary manner by the third air flow A3 from the second compressor 22 or by the fourth air flow A4 from the first compressor 21.

[0072] To this end, and again with reference to Figures 2 to 5, the non-propulsive turbomachine 2 includes a sampling valve 4 mounted on the first sampling channel 31, which is mounted between the main supply channel 30 and the second compressor 22, and configured to allow or prevent the flow of the second air stream A2 to the second compressor 22. In other words, the sampling valve 4 is configured to operate between: • a closed position PO (shown in [Fig. 5]) in which the circulation of the second airflow A2 is prohibited in the first sampling channel 31, the cabin air conditioning device 6 is then supplied only by the fourth airflow A4 which corresponds to a part of the pressurized airflow Ap circulating in the general supply channel 30, and • an open position PI (shown in [Fig.4]) in which the second airflow A2 circulates in the first sampling channel 31 and supplies the second compressor 22, which generates the third airflow A3 to supply the cabin air conditioning device 6.

[0073] According to a preferred aspect, the non-propulsive turbomachine 2 includes a first control valve 41, shown in Figures 3 to 5, mounted on the circulation channel 32 and configured to allow or prohibit the circulation of the third airflow A3 from the second compressor 22 to the cabin air conditioning device 6.

[0074] Similarly, the non-propulsive turbomachine 2 preferably includes a second control valve 42, shown in Figures 3 to 5, mounted on the second sampling channel 33 and configured to allow or prohibit the circulation of the fourth airflow A4 from the first compressor 21 to the cabin air conditioning device 6.

[0075] In one embodiment, with reference to [Fig.3], the non-propulsive turbomachine 2 includes a relief valve 43 mounted on the second sampling channel 33. The relief valve 43 is configured to lower, when necessary, the pressure of the fourth air stream A4 before its introduction into the cabin air conditioning device 6.

[0076] In order to control the opening and closing of the sampling valve 4, with reference to [Fig.3], the non-propulsive turbomachine 2 includes a control system 5 connected to the sampling valve 4. Preferably, the control system 5 is also connected to the first control valve 41 and the second control valve 42, as will be described in more detail later.

[0077] In practice, the control system 5 comprises a measuring device 50 for the pressure at the outlet of the first compressor 21 and / or the aircraft altitude, and a computer 9. The computer 9 is configured to receive a measurement from the measuring device 50 and to control the sampling valve 4 according to the measured pressure or altitude. For this purpose, the computer 9 is connected, in this example, by a data network, on the one hand, to the measuring device 50, and, on the other hand, to the sampling valve 4.

[0078] In a first embodiment, shown in [Fig. 3], the measuring device 50 is a pressure sensor mounted directly at the outlet of the first compressor 21. The computer 9 is then configured to receive a pressure measurement from the measuring device 50 and to control the sampling valve 4: • in the closed position PO, when the pressure measured by the measuring device 50 is greater than or equal to a predetermined pressure threshold, and • in the open position PI, when the pressure measured by the measuring device 50 is below the predetermined pressure threshold.

[0079] In other words, when the pressure of the pressurized airflow Ap at the outlet of the first compressor 21 is greater than or equal to the predetermined pressure threshold, the cabin air conditioning device 6 is supplied by the fourth airflow A4 taken from the general supply channel 30 and coming from the first compressor 21. Indeed, when the pressure of the pressurized airflow Ap is too high (due to the pressure of the ambient air entering through the outside air inlet EA), the circulation of the second airflow A2 is advantageously cut off, which makes it possible to avoid over-compression of the second airflow A2 in the second compressor 22, thus limiting the risk of damage to the latter.

[0080] When the pressure of the pressurized airflow Ap at the outlet of the first compressor 21 drops (due to the drop in pressure of the airflow A entering through the external air inlet EA), the circulation of the second airflow A2 is enabled and the second compressor 22 is powered. The latter is thus able to generate the third airflow A3 to supply the cabin air conditioning unit 6.

[0081] In this example, the predetermined pressure threshold is in the order of 2.5 to 4 bar (2.5x05 Pa to 4x05 Pa).

[0082] In a second embodiment (not shown), the measuring device 50 is an altimeter mounted on the aircraft in the vicinity or not of the non-propulsive turbomachine 2. The altimeter could alternatively correspond to an altimeter already mounted in the cockpit of the aircraft to enable piloting the aircraft.

[0083] The calculator 9 is then configured to receive an altitude measurement from the measuring device 50 and to control the sampling valve 4: • in the closed position PO when the altitude determined by the measuring device 50 is less than or equal to a predetermined altitude threshold, and • in the open position PI when the altitude determined by the measuring device 50 is greater than the predetermined altitude threshold.

[0084] In this example, the predetermined altitude threshold is in the range of 1000 to 4000 m.

[0085] In other words, at low altitude (for example, when the aircraft is on the ground and the outside pressure is higher than the pressure required to reach the expected pressure in the cabin air conditioning unit 6 with the predetermined compression ratio of the second compressor 22), closing the bleed valve 4 prevents the second compressor 22 from being supplied, and therefore does not generate the third airflow A3. The cabin air conditioning unit 6 is supplied by the fourth airflow A4 from the first compressor 21.

[0086] Conversely, at high altitude, the pressure of the airflow A entering the first compressor 21 corresponds to the pressure required to reach the outlet pressure of the second compressor 22, which is necessary to supply the cabin air conditioning system 6. Thus, opening the sampling valve 4 allows supplying the second compressor 22, which generates the third airflow A3 to supply the cabin air conditioning device 6. The second airflow A2 being taken from the outlet of the first compressor 21, the latter is already pre-compressed, which allows the second compressor 22 to be sized less, while still reaching the expected air pressure in the cabin air conditioning device 6.

[0087] In one embodiment, as described above, the control device 5 is also configured to control the first regulating valve 41, mounted on the circulation channel 32 between the second compressor 22 and the cabin air conditioning device 6, and the second regulating valve 42, mounted on the second sampling channel 33 between the first compressor 21 and the cabin air conditioning device 6.

[0088] Preferably, the control device 5 is configured to control each regulating valve 41, 42 according to the state of the sampling valve 4. In practice, the control device 5 is configured to: • when the sampling valve 4 is in the closed position PO (as shown in [Fig. 5]), control the second regulating valve 42 in the open position PI, so as to allow the cabin air conditioning unit 6 to be supplied with the fourth airflow A4, and • when the sampling valve 4 is in the open position PI (as shown in [Fig.4]), command the first control valve 41 to the open position PI, so as to allow the supply of the cabin air conditioning device 6 with the third airflow A3, and the second control valve 42 to the closed position PO to cut off the circulation of the fourth airflow in the second sampling channel 33.

[0089] In one embodiment, with reference to [Fig. 5], the non-propulsive turbomachine 2 includes a clutch device 8 mounted on the turbomachine shaft 25. The clutch device 8 is configured to disengage the second compressor 22 from the turbomachine shaft 25, so as to drive only the first compressor 21 in rotation by the gas turbine 24. Thus, the mechanical energy generated by the gas turbine 24 that is not useful for the rotation of the first compressor 21 can advantageously be used to generate additional electrical energy in the electric generator G, for example.

[0090] A method for operating the non-propulsive turbomachine 2, as described above, will now be described in an embodiment with reference to Figures 4 and 5. In this example, the non-propulsive turbomachine 2 comprises an electric generator G connected to the turbomachine shaft 25 and a heat exchanger 7 mounted on the fuel circuit 1. The non-propulsive turbomachine 2 includes a pressure sensor type measuring device 50 mounted on the general supply channel 30 at the outlet of the first compressor 21. It is understood that the process works in a similar way for an altimeter type measuring device 50.

[0091] In this embodiment, the aircraft is initially at a low altitude, for example on the ground, before takeoff. The pressure of the ambient airflow A entering the air inlet EA is on the order of 1 bar (1015 hPa). The sampling valve 4 is initially in the closed position PO, and the circulation of the second airflow A2 in the first sampling channel 31 is prohibited, thus preventing any risk of over-compression in the second compressor 22.

[0092] The non-propulsive turbomachine 2 is activated and an ambient airflow A enters the air inlet EA and circulates, in a first stage El, in the first compressor 21, in which it is compressed.

[0093] At the outlet of the first compressor 21, the first pressurized airflow Ap flows into the general supply channel 30 and the first airflow Al supplies the combustion chamber 23. The second control valve 42 is open, so that the fourth airflow A4 taken from the general supply channel 30 flows into the second sampling channel 33 and supplies the cabin air conditioning device 6.

[0094] In a second step E2, the measuring device 50, a pressure sensor, measures a pressure value of the pressurized airflow Ap at the outlet of the first compressor 21. The measuring device 50 then sends this measurement to the computer 9, which compares it with a predetermined pressure threshold. In this example, the predetermined pressure threshold is between 2.5 bar and 4 bar (2.5 x 10⁵ Pa to 4 x 10⁵ Pa), corresponding to the pressure of the pressurized airflow Ap exiting the first compressor 21 for an ambient airflow A entering through the external air inlet EA at a pressure between 0.9 and 1 bar (corresponding to the air pressure between 0 and 1000 m altitude). Due to the aircraft's low altitude, and therefore the low inlet pressure of the ambient airflow A, the computer 9 detects that the measured pressure is higher than the predetermined pressure threshold.The sampling valve 4 remains in the closed position PO and the fourth airflow A4 supplies the cabin air conditioning device 6.

[0095] When the aircraft takes off and the altitude increases, the air pressure at the inlet of the first compressor 21 decreases, as does the pressure at the outlet.

[0096] The measuring device 50, of the pressure sensor type, preferably measures, on a recurring basis, the pressure of the pressurized airflow Ap at the outlet of the first compressor 21 and sends the measurement to the computer 9 which compares it with the predetermined pressure threshold.

[0097] When the pressure of the pressurized airflow Ap at the outlet of the first compressor 21 is below the predetermined pressure threshold, the computer 9 commands the sampling valve 4 to the open position PI, so as to allow the circulation of the second airflow A2 in the first sampling channel 31. The second compressor 22, thus supplied, generates a third airflow A3 which supplies the cabin air conditioning device 6. Since the pressurized airflow Ap at the outlet of the first compressor 21 is at a pressure below the predetermined pressure threshold, the second airflow A2 drawn from the general supply channel 30 is at a pressure which, combined with the predefined compression ratio of the second compressor 22, makes it possible to generate a third airflow A3 at the expected pressure in the cabin air conditioning device 6.The latter is thus supplied with an airflow at the expected pressure, and no risk of over-compression can occur.

[0098] Preferably, the first control valve 41 is open and the second control valve 42 is closed, so as to prohibit the circulation of the fourth airflow A4 in the second sampling channel 33. The cabin air conditioning device 6 is supplied only by the third airflow A3.

[0099] In a second embodiment, the aircraft is initially at high altitude, for example in cruise. The pressure of the ambient airflow A entering the air inlet EA is approximately 0.2 bar (2 x 10⁴ Pa). The sampling valve 4 is initially in the open position PI, and the second airflow A2 flows through the first sampling channel 31 and supplies the second compressor 22. The latter generates the third airflow A3 at the expected pressure and supplies the cabin air conditioning unit 6. In this example, the first control valve 41 is open to supply the cabin air conditioning unit 6 with the third airflow A3 from the second compressor 22, and the second control valve 42 is closed to prevent the fourth airflow A4 from flowing through the second sampling channel 33.

[0100] The measuring device 50, of the pressure sensor type, preferably measures recurrently the pressure of the pressurized airflow Ap at the outlet of the first compressor 21 and sends the measurement to the computer 9 which compares it with the predetermined pressure threshold.

[0101] When the pressure of the pressurized airflow Ap at the outlet of the first compressor 21 is greater than the predetermined pressure threshold, the computer 9 commands the sampling valve 4 to the closed position PO, so as to prohibit the circulation of the second airflow A2 in the first sampling channel 31 and thus avoid any risk of over-compression in the second compressor 22.

[0102] Preferably, the second regulating valve 42 is open, so as to allow the circulation of the fourth airflow A4 in the second sampling channel 33 to supply the cabin air conditioning device 6.

Claims

1. Demands Non-propulsive turbomachine (2) for a fuel conditioning system (SC) (Q) configured to supply an aircraft turboshaft engine (M) with fuel (Q) from a cryogenic tank (R), the non-propulsive turbomachine (2) comprising: • a first compressor (21) configured to be supplied by an ambient air flow (A) and to generate a pressurized air flow, • a combustion chamber (23) configured to be supplied, on the one hand, by a fuel flow (Q2) from the cryogenic tank (R), and, on the other hand, by a first air flow (Al) circulating in a general supply channel (30) connected to the first compressor (21), the combustion chamber (23) being configured to discharge an exhaust gas flow (FE) laden with calories, • a second compressor (22) connected on the one hand to the general supply channel (30) by a first sampling channel (31) so as to be supplied with a second airflow (A2) from the first compressor (21), and on the other hand, configured to be connected to a cabin air conditioning device (6) by a circulation channel (32), so as to supply it with a third airflow (A3), • a single gas turbine (24) connected to both the first compressor (21) and the second compressor (22) by a single turbomachine shaft (25), the gas turbine (24) being configured to be driven in rotation by the exhaust gas flow (FE) from the combustion chamber (23) and to drive simultaneously the first compressor (21) and the second compressor (22), • a second sampling channel (33) connected to the main supply channel (30) and configured to be connected to the cabin air conditioning unit (6), so as to supply it with a fourth airflow (A4) from the first compressor (21), and • at least one sampling valve (4), mounted on the first sampling channel (31) between the general supply channel (30) and the second compressor (22), the sampling valve (4) being configured to allow or prohibit the circulation of the second airflow (A2) in the sampling channel (31) so as to supply the cabin air conditioning device (6) with the third airflow (A3) and / or the fourth airflow (A4).

2. Non-propulsive turbomachine (2) according to claim 1, the non-propulsive turbomachine (2) comprising: • a first control valve (41) mounted on the circulation channel (32) and configured to at least allow or prohibit the circulation of the third air stream (A3) from the second compressor (22) to the cabin air conditioning device (6), and • a second control valve (42) mounted on the second sampling channel (33) and configured to at least allow or prohibit the circulation of the fourth air stream (A4) from the first compressor (21) to the cabin air conditioning device (6).

3. Non-propulsive turbomachine (2) according to any one of claims 1 to 2, the non-propulsive turbomachine (2) comprising a control system (5) for the sampling valve (4), the control system (5) comprising a measuring device (50) for the pressure at the outlet of the first compressor (21) and / or the altitude of the aircraft, and a computer (9) connected to the measuring device (50) and to the sampling valve (4) and configured to control the sampling valve (4) according to the measured pressure and / or the determined altitude.

4. Non-propulsive turbomachine (2) according to claim 3, wherein the measuring device (50) is a pressure sensor mounted directly at the outlet of the first compressor (21), the computer (9) being configured to receive a measurement from the measuring device (50) and to control the sampling valve (4): • in the closed position (PO) when the pressure measured by the measuring device (50) is greater than or equal to a predetermined pressure threshold, • in the open position (PI) when the pressure measured by the measuring device (50) is less than the predetermined pressure threshold.

5. Non-propulsive turbomachine (2) according to claim 3, wherein the measuring device (50) is an altimeter, the computer (9) being configured to receive a measurement from the measuring device (50) and to control the sampling valve (4) at least: • in the closed position (PO) when the altitude determined by the measuring device (50) is less than a predetermined altitude threshold, so as to supply the cabin air conditioning device (6) with the fourth airflow (A4) from the first compressor (21), and • in the open position (PI) when the altitude determined by the measuring device (50) is greater than or equal to the predetermined altitude threshold, so as to supply the cabin air conditioning device (6) with the third airflow (A3) from the second compressor (22).

6. Non-propulsive turbomachine (2) according to any one of claims 1 to 5, the non-propulsive turbomachine (2) comprising a heat exchanger (7) configured to reheat the fuel stream (Q) from calories transferred by the exhaust gas stream (FE) of the gas turbine (24).

7. Non-propulsive turbomachine (2) according to any one of claims 1 to 6, the non-propulsive turbomachine (2) comprising an electric generator (G) connected to the turbomachine shaft (25) and configured to generate electrical power to supply an aircraft electrical network.

8. Non-propulsive turbomachine (2) according to any one of claims 1 to 7, the non-propulsive turbomachine (2) comprising a clutch device (8) mounted on the turbomachine shaft (25) and configured to disengage the second compressor (22), so as to drive only the first compressor (21) in rotation by the gas turbine (24).

9. Fuel conditioning system (S) configured to supply at least one aircraft propulsion turboshaft engine (M), the conditioning system (S) comprising: • a cryogenic tank (R), • a fuel circuit (1) connected to the cryogenic tank (R) and configured to be connected to the propulsion turboshaft engine (M), a fuel flow (Q) circulating in the fuel circuit (1), and • a non-propulsive turbomachine (2) according to any one of claims 1 to 8, • the cryogenic tank (R) being configured to supply both the propulsion turboshaft engine (M) and the combustion chamber (23) of the non-propulsive turbomachine (2).

10. Conditioning system (SC) according to claim 9 combined with claim 6, wherein the heat exchanger (7) is mounted on the fuel circuit (1) so as to warm the fuel stream (Q) from the cryogenic tank (R).

11. Aircraft comprising at least one propulsion turboshaft engine (M) and a conditioning system (SC) according to any one of claims 9 to 10, the fuel (Q) circulating in the fuel circuit (1) supplying the propulsion turboshaft engine (M).

12. A method for operating the non-propulsive turbomachine (2) according to any one of claims 1 to 8, wherein the sampling valve is initially in a closed position, and circulation of the second air stream (A2) in the first sampling channel (31) is prohibited, the method comprising the steps of: • circulating an ambient air stream through the first compressor (21), the cabin air conditioning unit (6) being supplied by the fourth air stream from the first compressor (21), and • when the ambient air stream pressure is below a predetermined pressure threshold, controlling the sampling valve (4) so ​​as to permit circulation of the second air stream (A2) in the first sampling channel (31) and supply the second compressor (22), so as to supply the cabin air conditioning device (6) with the third airflow (A3).

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