Hybrid turbomachine for an aircraft with active sound control system

Abstract

Hybrid turbine (1) comprising an electric generator (2), a gas generator (3) equipped with an intake portion (31) and an exhaust portion (32), and an acoustic monitoring system (4) comprising a control unit (41) and a plurality of loudspeakers. At least one first loudspeaker (43) is arranged on the electric generator (2), and / or at least one second loudspeaker (45) is arranged on the intake portion (31) of the gas generator (31), and / or at least one third loudspeaker (47) is arranged on the exhaust portion (32) of the gas generator (3), the control unit (41) of the acoustic monitoring system (4) being installed on the electric generator (2) and being configured to convert the electromotive force of the electric generator (2) from alternating current to direct current so as to make it an adjustable direct voltage intended to be distributed to a load or to an energy storage device.

Description

TECHNICAL FIELD

[0001] The present invention relates to the field of aircraft propulsion system noise, and more particularly, to an active acoustic monitor for a hybrid turbogenerator of an aircraft, such as a vertical take-off aircraft. BACKGROUND

[0002] The emergence of a new market for flying city taxis requires an electric distributed propulsion architecture called series hybrid architecture, i.e. the combination of two different propulsion sources: a turbogenerator comprising a turbine and a generator, and a battery pack.

[0003] The democratization of this type of aircraft in large urban centers cannot be achieved without demonstrating optimized acoustic features on the turbogenerator.

[0004] The noise sources of a turbogenerator include: rolling noise, tonal noise, and combustion noise and turbine noise. Rolling noise is the noise emitted by the generator driven at high speed by the turbine. It is generated on the one hand by the vibrations of the rotating assembly and on the other hand by the internal contacts during rolling. The tonal noise associated with the compressor corresponds to the noise emitted by the intake of the turbogenerator. Combustion noise and turbine noise correspond to the noise emitted by the exhaust of the turbogenerator (broadband noise).

[0005] The principle of active acoustic monitoring is well known. However, its application on a turbine faces two fundamental problems: the complexity of the sound field to be attenuated, and the on-board mass necessary for effective operation.

[0006] For a turbine configured as a turbogenerator, the proximity of the different elements, in particular the power supply, allows to place the monitoring system as close as possible to the generator at a lower cost and to solve the mass loss problem.

[0007] As explained by Ulf Tapken et al. in the article entitled "Identification of broadband noise sources of a turbo-shaft engine" (AIAA-2014-3321), it is possible to monitor the injected broadband noise with a simple system comprising for example a loudspeaker, a microphone and an integrated single-channel controller with feedback monitoring. This system allows to monitor the noise with good attenuation up to about 1500 Hz, i.e. more than 15 dB, because its spatial structure is very simple.

[0008] The monitoring of the compressor tone requires the use of several loudspeakers and therefore the use of a multichannel system, as described in the article by R. Maier et al. entitled "Active Control of Fan Tone Noise from Aircraft Engines", 7th AIAA / CEAS Aeroacoustics Conference, 28-30 May 2001.

[0009] For several years, boxes have been installed on board aircraft equipped with turboprop engines to actively reduce the noise perceived in the nacelle. These systems are heavy. SUMMARY

[0010] The present invention aims to propose a solution for monitoring the acoustic noise emitted by a turbogenerator by limiting the mass associated with the acoustic monitoring system.

[0011] In one of the objectives of the present invention, a hybrid turbomachine is proposed, comprising a generator, a gas generator equipped with an air intake and an exhaust, and an acoustic monitoring system comprising a control unit and a plurality of loudspeakers.

[0012] According to a general characteristic of the invention, at least one first loudspeaker is arranged on the generator, and / or at least one second loudspeaker is arranged on the air intake of the gas generator, and / or at least one third loudspeaker is arranged on the exhaust of the gas generator.

[0013] This acoustic monitoring system thus allows the active attenuation of the noise generated by the hybrid turbomachine, perceived on the ground and in the nacelle. The sound waves emitted by the loudspeakers of the system generate acoustic waves intended to generate a compensation or even a cancellation of the waves generated by the turbomachine.

[0014] Preferably, the acoustic monitoring system comprises at least one first loudspeaker, at least one second loudspeaker and at least one third loudspeaker, the first loudspeaker being arranged on the generator, the second loudspeaker being arranged on the air intake of the gas generator, and the third loudspeaker being arranged on the exhaust of the gas generator.

[0015] The configuration of the simultaneous installation of loudspeakers on the generator, on the air intake and on the exhaust allows a maximum reduction of the noise.

[0016] According to a first aspect of the hybrid turbomachine, the acoustic monitoring system can comprise at least one first microphone arranged on the generator and associated with said at least one first microphone, and / or at least one second microphone arranged on the gas generator intake and associated with said at least one second microphone, and / or at least one third microphone arranged on the gas generator exhaust and associated with said at least one third microphone, the acoustic monitoring system further comprising a monitoring module configured to determine, for each loudspeaker, the signal to be emitted to the loudspeaker as a function of the positioning of the loudspeaker and of the signals collected by the at least one microphone associated with the loudspeaker.

[0017] According to a second aspect of the hybrid turbomachine, the turbomachine can comprise at least one intake duct defining the gas generator intake and at least one exhaust duct defining the gas generator exhaust, said at least one second loudspeaker being fixed to the wall of said at least one intake duct and said at least one third loudspeaker being fixed to the wall of said at least one exhaust duct.

[0018] According to a third aspect of the hybrid turbomachine, said at least one second microphone can be fixed to the wall of said at least one intake duct and said at least one third microphone being fixed to the wall of said at least one exhaust duct.

[0019] According to a fourth aspect of the hybrid turbomachine, the control unit of the acoustic monitoring system can comprise an analog amplifier equipped with an analog-to-digital converter for emitting the processed signals to the loudspeakers and collecting the signals from the microphones, and a digital controller of programmable logic array or digital signal processor type for acquiring and processing the digital signals.

[0020] According to a fifth aspect of the hybrid turbomachine, the control unit of the acoustic monitoring system can further comprise a database comprising simple noise models generated as a function of the operating parameters of the turbomachine and a determination module configured to determine the signal to be emitted to the loudspeakers as a function of the operating parameters of the turbomachine and of the positioning of the loudspeakers.

[0021] The database can be used in the configuration of an acoustic monitoring system without any microphones, to reduce the weight of the system and thus of the turbomachine, the system operating a noise prediction system based on pre-recorded models and operating parameters of the turbomachine.

[0022] The database can also be used in the configuration of an acoustic monitoring system equipped with microphones, the database being used in the event of failure of the microphones.

[0023] According to a sixth aspect of the hybrid turbomachine, the hybrid turbomachine can comprise a wired communication between the control unit and the loudspeakers.

[0024] In one variant, the hybrid turbomachine can comprise a wireless communication between the control unit and the loudspeaker.

[0025] According to a seventh aspect of the hybrid turbomachine, the control unit of the acoustic monitoring system can be installed on the electric generator.

[0026] The installation of the control unit of the acoustic monitoring system on the electric generator thus allows to reduce the length of the connection, thereby reducing the overall mass of the system.

[0027] According to an eighth aspect of the hybrid turbomachine, the control unit can be further configured to convert the electromotive force of the electric generator into an adjustable direct current voltage by alternating current-direct current conversion, the adjustable direct current voltage being intended to be distributed to the load or to the energy storage device.

[0028] Thanks to its configuration for converting the electromotive force of the electric generator into an adjustable direct current voltage by alternating current-direct current conversion to be distributed to the load or to the energy storage device, the control unit can simultaneously comprise the functions of an active rectifier control unit or ARCU and the control functions of the acoustic processing unit.

[0029] In addition, the control unit can also be configured to perform at least one additional function of at least one conversion of the power supply, one acquisition of data related to the electric generator and one management of the low-voltage power supply for powering the control stage.

[0030] According to a ninth aspect of the hybrid turbomachine, the acoustic monitoring system can be integrated into the control system of the electric generator.

[0031] According to a tenth aspect of the hybrid turbomachine, the electric generator can be a reversible electric machine.

[0032] The electric generator thus allows a bidirectional conversion of mechanical energy-electrical energy, i.e. mechanical-electrical conversion and electrical-mechanical conversion. The electric generator can generate a multiphase current, for example a three-phase current. The electric generator can thus be a motor-generator configured to operate in generator mode in a first condition and in motor mode in a second condition. The electric generator can be a synchronous or asynchronous electric machine.

[0033] In another object of the application, an aircraft is proposed, comprising an electronic engine control unit of the aircraft and at least one turbomachine as defined above, the turbomachine being associated with or integrated into said electronic engine control unit of the aircraft, the acronym also being called EECU.

[0034] Said electronic engine control unit can be integrated into a full authority digital engine control, the acronym also being called FADEC, of the turbomachine of the aircraft.

[0035] The hybrid turbomachine can also comprise an aircraft control system mainly comprising a fuel system configured to pump fuel into a tank of the aircraft and to inject fuel into a combustion chamber of the aircraft and said aircraft electronic engine control unit (EECU).

[0036] According to an aspect of the aircraft, the turbomachine control unit can be configured to ensure the management of the measurements provided by the sensors and the launching of commands from the modules for managing the on-board network of the aircraft.

[0037] The control unit can also be configured to monitor parameters of the engine such as the fuel flow rate based on the rotational speed of the gas generator or of the electric generator and other parameters such as the frequency of the electric generator or the load expectation of each electric propulsion chain. The control unit can be configured to monitor the fuel flow rate supplied to the turbomachine based on the rotational speed of the gas generator or of the electric generator, the frequency of the electric generator or the load expectation of each electric propulsion chain. BRIEF DESCRIPTION OF DRAWINGS

[0038] [ Figure 1 ] Figure 1 is a schematic cross-sectional view of a hybrid turbomachine according to an embodiment of the application. DETAILED DESCRIPTION

[0039] Figure 1 is a schematic cross-sectional view of a hybrid turbomachine according to an embodiment of the application.

[0040] The hybrid turbomachine 1 comprises an electric generator 2, a gas generator 3 and an acoustic monitoring system 4. The electric generator 2 is mechanically connected to the gas generator 3 via a mechanical shaft 5.

[0041] The electric generator is a reversible electric machine. It thus allows a bidirectional conversion of mechanical energy into electrical energy, i.e. a mechanical-electrical conversion and an electrical-mechanical conversion. The electric generator can generate a three-phase electric current.

[0042] The gas generator 3 comprises an air intake 31, an exhaust section 32, at least one compression stage 33, a combustion stage 34 and at least one turbine stage 35 injecting hot air via the exhaust section 32.

[0043] The air intake 31 comprises at least one air intake duct 310 defining the air intake 31 of the gas generator 3 and an exhaust duct 320 defining the exhaust section 32 of the gas generator 3.

[0044] In Figure 1In the example embodiment illustrated, the acoustic monitoring system 4 comprises a control unit 41 mounted on the generator 2, two first microphones 42 and four first loudspeakers 43 arranged around the generator 2, two second microphones 44 and four second loudspeakers 45 arranged on the gas inlet 31 of the gas generator 3, and two third microphones 46 and five third loudspeakers 47 arranged on the gas exhaust 32 of the gas generator 3. The control unit 41 is electrically coupled to the microphones 42, 44 and 46 and to the loudspeakers 43, 45 and 47 by means of cables, so as to enable wired connections for the transmission of signals.

[0045] The loudspeakers and microphones can be piezoelectric, electrodynamic or plasmonic.

[0046] More specifically, the first loudspeakers 43 and the first microphones 42 are fixed to the generator 2 or to the casing containing the generator 2, the second microphones 44 and the second loudspeakers 45 are fixed to the gas inlet duct 310, and the third microphones 46 and the third loudspeakers 47 are fixed to the gas exhaust duct 320.

[0047] The control unit 41 of the acoustic monitoring system 4 comprises an analog amplifier equipped with an analog-to-digital converter for transmitting processed signals to the loudspeakers 43, 45 and 47 and collecting signals from the microphones 42, 44 and 46, and a digital controller of the programmable logic array or digital signal processor type for acquiring and processing digital signals.

[0048] The control unit 41 of the acoustic monitoring system comprises a monitoring module configured to determine, for each loudspeaker 43, 45 and 47, the signal to be emitted to the loudspeaker as a function of the positioning of the loudspeaker and of the signals collected by the microphone 42, 44 and 46 associated with the loudspeaker.

[0049] In order to deal with the possibility of failure of one of the microphones 42, 44, 46, the control unit 41 of the acoustic monitoring system 4 also comprises a database comprising simple noise models generated as a function of the operating parameters of the turbomachine 1 and a determination module configured to determine, for each loudspeaker 43, 45 and 47, the signal to be emitted to the loudspeaker as a function of the operating parameters of the turbomachine 1 and as a function of the positioning of the loudspeaker.

[0050] The acoustic monitoring system 4 thus allows active attenuation of the noise generated by the hybrid turbomachine 1 to be perceived on the ground and in the cabin. The sound waves emitted by the loudspeakers 43, 45 and 47 of the system 4 generate sound waves that are out of phase with the waves collected by the microphones 42, 44 and 46, so as to create destructive interference with the waves generated by the turbomachine 1.

[0051] The turbomachine 1 is intended to be installed on an aircraft comprising an electronic engine control unit of the aircraft, acronym also called EECU. The turbomachine 1 is associated with or integrated into the electronic engine control unit of the aircraft. The electronic engine control unit is preferably integrated into the full authority digital engine control of the turbomachine of the aircraft, acronym also called FADEC.

[0052] Furthermore, the control unit 41 of the turbomachine 1 is configured to ensure the management of the measurements provided by the sensors and the commands of the start-up system from the modules for managing the on-board network of the aircraft.

[0053] The control unit 41 is configured to monitor the fuel flow rate supplied to the turbomachine 1 on the basis of the rotational speed of the gas generator 3 or of the electric generator 2, of the frequency of the electric generator 2 or of the load expectation of each electric propulsion chain.

Claims

1. A hybrid turbine (1) comprising a generator (2), a gas generator (3) equipped with an air inlet (31) and an exhaust (32), and an acoustic monitoring system (4) comprising a control unit (41), a plurality of microphones and a plurality of loudspeakers configured to emit noise-attenuating sound waves. in, At least the first microphone of the plurality of microphones is directly connected to the generator. The features are as follows: at least a first speaker (43) of the plurality of speakers is disposed on the generator (2), and / or at least a second speaker (45) of the plurality of speakers is disposed on the air inlet of the gas generator (31), and / or at least a third speaker (47) of the plurality of speakers is disposed on the exhaust section (32) of the gas generator (3); the control unit (41) of the acoustic monitoring system (4) is mounted on the generator (2) and configured to convert the electromotive force of the generator (2) from AC to DC to make it an adjustable DC voltage, the adjustable DC voltage intended to be distributed to a load or energy storage device; wherein the control unit of the acoustic monitoring system further includes a database and a determination module, the database including a noise model generated based on the operating parameters of the hybrid turbine; the determination module is configured to: for each of the plurality of speakers, in response to a failure of one of the plurality of microphones, determine, based on i) the operating parameters of the hybrid turbine and ii) the location of the corresponding speaker, a corresponding first signal to be emitted to the corresponding speaker based on the noise model, and The acoustic monitoring system attenuates noise generated by the hybrid turbine by emitting sound waves from the plurality of speakers, wherein the sound waves emitted from the plurality of speakers are out of phase with the sound waves received by the plurality of microphones.

2. The hybrid turbine (1) according to claim 1, characterized in that, The acoustic monitoring system (4) includes at least one first microphone (42) and / or at least one second microphone (44) and / or at least one third microphone (46), the first microphone being disposed on the generator (2) and associated with the at least one first loudspeaker (43), the second microphone being disposed on the air inlet (31) of the gas generator (3) and associated with the at least one second loudspeaker (45), and the third microphone being disposed on the exhaust section (32) of the gas generator (3) and associated with the at least one third loudspeaker (47). The control unit (41) of the acoustic monitoring system (4) further includes a monitoring module configured to determine, for each loudspeaker (43, 45, 47), the signal to be transmitted to the loudspeaker (43, 45, 47) based on the location of the loudspeaker (43, 45, 47) and the signals collected by the at least one microphone (42, 44, 46).

3. The hybrid turbine (1) according to claim 1, characterized in that, The device includes at least one inlet pipe (310) defining the inlet (31) of the gas generator (3) and at least one exhaust pipe (320) defining the exhaust section (32) of the gas generator (3), the at least one second speaker (45) being fixed to the wall of the at least one inlet pipe (31) and the at least one third speaker (47) being fixed to the wall of the at least one exhaust pipe (320).

4. The hybrid turbine (1) according to claim 2, characterized in that, The device includes at least one inlet pipe (310) defining the inlet (31) of the gas generator (3) and at least one exhaust pipe (320) defining the exhaust section (32) of the gas generator (3), the at least one second speaker (45) being fixed to the wall of the at least one inlet pipe (31) and the at least one third speaker (47) being fixed to the wall of the at least one exhaust pipe (320).

5. The hybrid turbine (1) according to claim 2 in conjunction with claim 4, characterized in that, The at least one second microphone (44) is fixed to the wall of the at least one air inlet pipe (310), while the at least one third microphone (46) is fixed to the wall of the at least one exhaust pipe (320).

6. The hybrid turbine (1) according to claim 4 in combination with any one of claims 3 or 4, characterized in that, The control unit (41) of the acoustic monitoring system (4) includes an analog amplifier equipped with: an analog-to-digital converter for transmitting processed signals to the loudspeakers (43, 45, 47) and collecting signals from the microphones (42, 44, 46); and a digital controller of the type of programmable logic array or digital signal processor for acquiring and processing digital signals.

7. The hybrid turbine (1) according to any one of claims 1 to 5, characterized in that, The control unit (41) of the acoustic monitoring system (4) further includes a database and a determination module. The database includes a simple noise model generated based on the operating parameters of the turbine (1). The determination module is configured to determine the signal to be transmitted to each loudspeaker (43, 45, 47) based on the operating parameters of the turbine (1) and the location of the loudspeakers (43, 45, 47).

8. The hybrid turbine (1) according to any one of claims 1 to 5, characterized in that, This includes wired communication between the control unit (41) and the speakers (43, 45, 47).

9. The hybrid turbine (1) according to any one of claims 1 to 5, characterized in that, This includes wireless communication between the control unit (41) and the speakers (43, 45, 47).

10. The hybrid turbine (1) according to any one of claims 1 to 5, characterized in that, The acoustic monitoring system (4) is integrated into the control system of the generator (2).

11. The hybrid turbine (1) according to any one of claims 1 to 5, characterized in that, The generator (2) is a reversible motor.

12. An aircraft comprising an electronic engine control unit and at least one hybrid turbine (1) according to any one of claims 1 to 10, the hybrid turbine being associated with or integrated therein with the electronic engine control unit of the aircraft.

13. The aircraft according to claim 12, characterized in that, The electronic engine control unit is integrated into the full authority digital engine control of the aircraft turbine.

14. The aircraft according to claim 12 or 13, characterized in that, The control unit (41) is configured to ensure management of measurements provided by the sensors and system commands for starting the turbine (1) from the module used to manage the onboard network of the aircraft.

15. The aircraft according to claim 12 or 13, characterized in that, The control unit (41) is configured to monitor the fuel flow rate supplied to the turbine (41) based on the rotational speed of the gas generator (3) or the generator (2), the frequency of the generator (2), or the expected load of each electric propulsion chain.

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