HYDROGEN SUPPLY SYSTEM FOR A TURBOMACHINE AND TEMPERATURE CONTROL DEVICE FOR SUCH A HYDROGEN SUPPLY SYSTEM

Abstract

Temperature control device for a turbomachine hydrogen supply system, comprising a heat transfer fluid circuit (3) including: - a heat exchanger (31) on a turbomachine hydrogen supply line to control the hydrogen temperature, - a heat exchanger (32) on a turbomachine nozzle to extract heat from the air in the nozzle's primary intake, in parallel with a bypass valve (36), - a heat transfer fluid flow generator (34) and an electric heat transfer fluid heater (35) between the heat exchangers, - a control system to: - control the flow generator (34) according to a flow setpoint and a flow measurement in the heat transfer fluid circuit (3), - detect a transient acceleration regime of the turbomachine, and if detected, control the electric heater (35) and the bypass valve (36). Figure for the abbreviated version: Figure 6

Description

Title of the invention: HYDROGEN SUPPLY SYSTEM FOR A TURBOMACHINE AND TEMPERATURE CONTROL DEVICE FOR SUCH A HYDROGEN SUPPLY SYSTEM technical field

[0001] The present invention relates, in general, to a hydrogen supply system for a turbomachine, such as an aircraft engine, using hydrogen as fuel. More particularly, it relates to a temperature control device for a hydrogen supply system of such a turbomachine. Prior state of the art

[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 currently in operation, 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 impacts, with the aim of improving the energy efficiency of aircraft. Consequently, the Applicant is constantly working to reduce its climate impact by employing 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.

[0004] This sustained research and development work focuses on both new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, and the development of the use of new technologies as alternatives to fossil fuels to provide propulsion.

[0005] In this context, a hydrogen supply system for a turbomachine, more particularly for an aircraft engine, has the function of providing a controlled flow of hydrogen to the injectors located in a combustion chamber of the turbomachine.

[0006] The turbomachine's hydrogen supply system comprises a hydrogen supply line including the following elements in series, according to a direction of hydrogen flow, from upstream to downstream:

[0007] - a liquid hydrogen reservoir,

[0008] - a liquid hydrogen pressurization device,

[0009] - a heating element intended to raise the temperature of the liquid hydrogen in order to allow its evaporation into hydrogen gas,

[0010] - a dosing device intended to dose the mass flow rate of gaseous hydrogen in combustion chamber inlet, and

[0011] - a shut-off valve.

[0012] The shut-off valve is connected to a supply line which is connected to the injectors of the turbomachine.

[0013] The heating intended to raise the temperature of the liquid hydrogen so as to allow its evaporation into gaseous hydrogen is a critical point in the hydrogen supply line.

[0014] In the case of a transient turbomachine acceleration regime, there is a delay between a change in the thermal power required to vaporize hydrogen and the change in available thermal power. This delay is explained in particular by the time required for the change in hydrogen flow rate at the injectors to affect the temperature of the air inlet to a heat exchanger at a turbomachine nozzle, as well as by the inertia of this exchanger.

[0015] To solve this problem, it is possible to oversize components such as heat exchangers, particularly the turbomachine's nozzle heat exchanger. Oversizing the turbomachine's nozzle heat exchanger can "counter" the cold flow demand while the exchanger is able to supply the necessary thermal power. However, such oversizing leads to other problems, such as increased cost and weight. Description of the invention

[0016] The invention aims to solve the problems of the prior art by providing a temperature control device for a hydrogen supply system of a turbomachine, the hydrogen supply system comprising a component of pressurization and a metering device arranged in series on a hydrogen supply line to the turbomachine,

[0017] characterized in that the control device comprises a heat transfer fluid circuit including:

[0018] - a first heat exchanger configured to be located between the pressurization unit and The dosing unit on the hydrogen supply line is configured to control the hydrogen temperature.

[0019] - a second heat exchanger configured to be located on a nozzle of the turbomachine and configured to extract calories from the air in the primary nozzle vein,

[0020] - a heat transfer fluid flow generator and an electric fluid heater heat transfer fluids, arranged in series between the first and second heat exchangers,

[0021] - a bypass valve located in parallel with the second exchanger located in the nozzle of the turbomachine,

[0022] - a control system configured for

[0023] - control the flow generator according to a fluid flow setpoint heat transfer fluid and a measurement of the heat transfer fluid flow rate in the heat transfer fluid circuit,

[0024] - detect a transient acceleration regime of the turbomachine, and in the event of detection of transient acceleration regime of the turbomachine, control of the electric heater and bypass valve during said transient acceleration regime.

[0025] Thanks to the invention, the electric heater can be used as an additional source of thermal power during transient regimes of the turbomachine, such as a transient acceleration regime. Thus, the additional thermal power requirements for vaporizing hydrogen during the turbomachine's transient regime are met.

[0026] According to a preferred feature, the control system includes an engine control module connected to an electric heater setpoint determination module, the electric heater setpoint determination module being connected to the electric heater, the engine control module being configured to detect a transient acceleration regime of the turbomachine and in the event of detection of a transient acceleration regime, configured to command the electric heater setpoint determination module to transmit an operating setpoint to the electric heater.

[0027] According to a preferred feature, the electric heater setpoint control module is configured to control the electric heater, during a transient regime of the turbomachine, according to a modulating electrical power determined in such a way as to be able to compensate for a thermal power deficit of the second exchanger.

[0028] According to a preferred feature, the control system includes a regulator connected to the bypass valve and configured to control said valve based on a measurement of hydrogen temperature in the turbomachine's hydrogen supply line and a temperature setpoint provided by the engine control module.

[0029] According to a preferred feature, the control system includes an engine control module connected to a bypass valve setpoint determination module, the bypass valve setpoint determination module being connected to the bypass valve, the engine control module being configured to detect a transient acceleration regime of the turbomachine and in the event of detection of a transient acceleration regime, configured to command the bypass valve setpoint determination module to transmit to the bypass valve of the second nozzle exchanger of the turbomachine a fully closed setpoint so as to maximize the thermal power supplied by the second nozzle exchanger of the turbomachine.

[0030] According to a preferred feature, the control system includes a controller connected to the electric heater and configured to control said heater based on a temperature measurement of hydrogen in the turbomachine's hydrogen supply line and a temperature setpoint provided by the engine control module.

[0031] The invention also relates to a hydrogen supply system for a turbomachine, characterized in that it comprises a control device as previously described.

[0032] The invention also relates to a turbomachine comprising injectors, characterized in that it comprises a hydrogen supply system as previously described, connected to said injectors.

[0033] The invention also relates to an aircraft comprising a turbomachine as previously described.

[0034] The hydrogen supply system of a turbomachine, the turbomachine, and the aircraft offer advantages similar to those previously described. Brief description of the drawings

[0035] Other features and advantages will become apparent from the following description of a preferred embodiment, given by way of non-limiting example, described with reference to the figures in which:

[0036] [Fig.l] schematically illustrates a hydrogen supply system for a turbomachine;

[0037] [Fig.2] schematically illustrates an embodiment according to the invention of a heating circuit included in the hydrogen supply system of a turbomachine;

[0038] [Fig.3] schematically illustrates different control modes of a heat transfer fluid circuit included in the heating circuit of [Fig.2] and the possible transitions between the modes, according to one embodiment of the invention;

[0039] [Fig.4] illustrates a first method of controlling the heat transfer fluid circuit, according to an embodiment of the invention;

[0040] [Fig.5] illustrates a second control method for the heat transfer fluid circuit, according to an embodiment of the invention;

[0041] [Fig.6] illustrates a third method of controlling the heat transfer fluid circuit, according to an embodiment of the invention;

[0042] [Fig.7] illustrates a variant of the third control mode of the heat transfer fluid circuit;

[0043] [Fig.8] illustrates an alternative embodiment of the heating circuit.

[0044] Identical, similar or equivalent parts of the different figures bear the same numerical references so as to facilitate the transition from one figure to another.

[0045] The different parts represented in the figures are not necessarily shown on a uniform scale in order to make the figures more legible.

[0046] The different possibilities (variants and embodiments) should be understood as not being mutually exclusive and can be combined. Detailed description of the embodiments

[0047] To simplify the presentation, we first describe, with reference to [Fig. 1], a hydrogen supply system for a turbomachine, and then, with reference to [Fig. 2], a heating circuit according to the invention, which can be included in the hydrogen supply system of [Fig. 1].

[0048] Fig. 1 schematically presents a hydrogen supply system for a turbomachine capable of providing a controlled flow of hydrogen to injectors 100 located in a combustion chamber of the turbomachine.

[0049] More specifically, [Fig.1] represents the hydrogen supply line of the turbomachine. The hydrogen supply line comprises, according to a direction of hydrogen flow from upstream to downstream, a hydrogen reservoir 1, in particular in which the hydrogen is in a cryogenic liquid state, in particular at low pressure, for example of an order of magnitude between 2 bars and 3 bars, and at low temperature, for example of an order of magnitude between 10K and 30K, for example 20K.

[0050] The hydrogen tank 1 is connected to a pressurization device 2 designed to increase the pressure of the hydrogen, in particular liquid hydrogen. The hydrogen pressure increase is carried out in such a way as to maintain a hydrogen injection pressure higher than the combustion chamber pressure of the turbomachine.

[0051] At a given injected hydrogen flow rate, the difference between the pressure at the outlet of the pressurization device 2 and the pressure in the combustion chamber must therefore be equal to or greater than the sum of the pressure losses of the various equipment of the hydrogen supply system.

[0052] The pressurization device 2 can, for example, be a pump, in particular a centrifugal pump, or several pumps, in particular several centrifugal pumps, in series.

[0053] The pressurization member 2 is connected to a heating circuit 3. An embodiment according to the invention of heating circuit 3 is described in detail with reference to [Fig.2].

[0054] The heating circuit 3 is connected to a dosing device 5 intended to dose a mass flow rate of hydrogen, in particular gaseous hydrogen, into the combustion chamber.

[0055] The metering element 5 can, for example, be a variable area metering valve or a pressure regulator coupled to a sonic neck.

[0056] The metering device 5 is connected to a shut-off device 6 intended to isolate the hydrogen supply system from the combustion chamber of the turbomachine.

[0057] The shut-off element 6 can, for example, be an "on or off" type shut-off valve.

[0058] The shut-off device 6 is connected to a supply line connected to the injectors 100 located in the combustion chamber of the turbomachine. The injectors 100 and the combustion chamber are conventional and are not detailed here.

[0059] It should be noted that the hydrogen supply system includes several temperature sensors, one of which is shown. Temperature sensor 7 is located between the heating circuit 3 and the metering unit 5. The temperature sensors are intended, in particular, to measure the temperature of the gaseous hydrogen at the injection point.

[0060] Alternatively, the sensor 7 is located between the metering unit 5 and the shut-off valve 6, or between the shut-off valve 6 and the injectors 100. Indeed, at the orders of magnitude of the temperature seen by the temperature sensor at the injection point, for example between 200 K and 350 K, the gaseous hydrogen undergoes little temperature variation during isenthalpic compression / expansion, that is, compression / expansion caused by a pressure drop. For example, the pressure drop across the metering unit 5, which is on the order of several tens of bar, causes the temperature to vary by only about 0.1 K.

[0061] Figure 2 illustrates an embodiment of the heating circuit according to the invention. 3. The heating circuit 3 comprises the following elements.

[0062] The heating circuit 3 is a circuit, or loop, with a heat transfer fluid. It includes a first heat exchanger 31 located on the hydrogen supply line, between the pressurization unit 2 and the dosing unit 5.

[0063] The first heat exchanger 31 is designed to raise the temperature of the hydrogen, particularly liquid hydrogen. Such a temperature increase ensures the evaporation of the hydrogen entering the heating circuit 3 into gaseous hydrogen, while controlling a range of temperatures permissible for hydrogen combustion.

[0064] The first heat exchanger 31 can be a single heat exchanger or several heat exchangers in series to, for example, manage intermediate temperature levels of a fluid, each of the several heat exchangers being able to reach a given temperature level. It can, for example, be a tube or plate heat exchanger.

[0065] The heating circuit 3 also includes a second heat exchanger 32 located in a nozzle of the turbomachine and designed to extract heat from the air in the primary intake of the nozzle. The temperature and air flow rate in the nozzle are determined by the operation of the turbomachine. The purpose of the second heat exchanger 32 is to provide thermal power to achieve a range of hydrogen injection temperatures suitable for hydrogen combustion. This thermal power is transferred from the second heat exchanger 32 in the turbomachine nozzle to the first heat exchanger 31 by the heat transfer fluid.

[0066] The second exchanger 32 can, for example, be a tube or plate exchanger using part or all of the primary flow from the turbomachine.

[0067] The heat transfer fluid can, for example, be supercritical nitrogen, supercritical carbon dioxide or helium.

[0068] The heat transfer fluid circuit 3 includes, from the first heat exchanger 31, a flow generator 34, or circulator, intended to ensure the circulation of the heat transfer fluid.

[0069] The flow generator 34 can, for example, be a positive displacement or centrifugal pump.

[0070] The heat transfer fluid circuit 3 also includes an electric heater 35 intended to supply heat to the heat transfer fluid in the event that the second heat exchanger 32 in the turbomachine nozzle does not supply enough. This point is detailed below.

[0071] The electric heater 35 can, for example, be an exchanger with continuously regulated or on-off regulated electrical power.

[0072] The heat transfer fluid circuit 3 also includes a bypass valve 36, connected in parallel with the second heat exchanger 32, allowing a portion to be diverted adjustable flow rate of heat transfer fluid passing through the second exchanger 32 in the nozzle of the turbomachine.

[0073] The heat transfer fluid circuit 3 includes several temperature sensors, two of which are shown. Temperature sensors 37 and 38 are respectively intended to measure the temperature of the heat transfer fluid upstream of the first heat exchanger 31 and the temperature of the heat transfer fluid upstream of the second heat exchanger 32.

[0074] The temperature control of the hydrogen supply system of a turbomachine with the heat transfer fluid circuit is a three-control system: the heat transfer fluid flow generated by the circulator 34, the electrical power of the electric heater 35 and the section of the bypass valve 36.

[0075] The objective of this system is to regulate the hydrogen temperature at the injection point. To achieve this, three control modes are distinguished, which correspond respectively to three operating phases of the turbomachine.

[0076] The following operating phases of the turbomachine are considered:

[0077] - Before starting the turbomachine: preparation and initialization of the start-up of the turbomachine;

[0078] - During turbomachine start-up: introduction and ignition of hydrogen in the combustion chamber of the turbomachine;

[0079] - At the end of start-up and / or above the idle speed of the turbomachine. The idle speed of a turbomachine corresponds to the operating state where the machine rotates at its minimum stable speed with no load or with minimal load. The end of the start-up phase is the point at which the turbomachine reaches this operating state.

[0080] The corresponding control modes are: - Initialization, or preheating, of the heat transfer fluid circuit 3; - The closed-loop regulation of the heat transfer fluid circuit 3 by the thermal power supplied by the electric heater 35 during a start-up phase of the turbomachine; - The closed-loop regulation of the heat transfer fluid circuit 3 by the thermal power supplied by the second exchanger 32, for example during operating phases at the end of the turbomachine start-up and / or above the turbomachine idle speed.

[0081] This control system takes into account multiple internal constraints of the heat transfer fluid circuit 3, including the minimum and maximum temperatures in the heat transfer fluid circuit 3.

[0082] The present invention relates more particularly to the third mode.

[0083] With reference to [Fig.3], the different control modes of the heat transfer fluid circuit and the possible transitions between the modes are described by a state diagram.

[0084] From a stopped state of the MO motor, when starting the motor, it is possible to switch to a first mode Ml which is the initialization, or preheating, mode of the heat transfer fluid circuit 3.

[0085] From the first mode M1, it is possible to switch to a second mode M2 ​​which is the closed loop regulation of the heat transfer fluid circuit 3 by the thermal power supplied by the electric heater 35.

[0086] From the second mode M2, it is possible to switch to a third mode M3 which is the closed loop regulation of the heat transfer fluid circuit 3 by the thermal power supplied by the second exchanger 32.

[0087] From the third mode M3, it is possible to return to the engine stop state.

[0088] The transitions from the first mode M1 to the second mode M2 ​​and from the second mode M2 ​​to the third mode M3 are detailed below.

[0089] Fig. 4 illustrates the first mode Ml of initialization, or preheating, of the heat transfer fluid circuit 3.

[0090] In this mode, since there is no hydrogen flow in the hydrogen supply line yet, it is not possible to directly regulate the hydrogen temperature at the injection.

[0091] Furthermore, the heat transfer fluid circuit 3 must be preheated before initiating a hydrogen flow to avoid: - A possible freezing of the heat transfer fluid if the latter has a solidification temperature that is too high compared to the use of cryogenic hydrogen at the inlet of the first exchanger 31 of the hydrogen supply line; - A temperature that is too low at the outlet of the first exchanger 31 of the hydrogen supply line compared to the temperature sizing of the equipment of the hydrogen supply line downstream of the latter.

[0092] The following two regulations are therefore put in place in the first ML mode. These are closed loop regulations of the flow generator 34 on the one hand and of the electric heater 35 on the other.

[0093] First, a calculation module 40 determines a temperature setpoint for the heat transfer fluid. Preferably, the temperature setpoint for the heat transfer fluid is calculated "offline" so as to obtain approximately the desired temperature at the injection point at the initialization of the hydrogen flow.

[0094] The temperature sensor 37 provides a temperature measurement value of the heat transfer fluid upstream of the first heat exchanger 31. The calculation module 40 and the Temperature sensors 37 are connected to the inputs of a subtractor 41, to provide it respectively with the temperature setpoint and the temperature measurement value.

[0095] The subtractor 41 calculates the difference between the input values ​​and provides a temperature error as output to a controller 42. The controller 42 determines an electric heater command based on the temperature error. The controller 42 is connected at its output to the electric heater 35 and transmits the electric heater command to it to modulate its power, thereby regulating the temperature of the heat transfer fluid.

[0096] Secondly, a calculation module 43 determines a heat transfer fluid flow setpoint. The heat transfer fluid flow setpoint is calculated "offline" so as to obtain internal temperatures in the heat transfer fluid circuit within the acceptable limits of the system.

[0097] A flow sensor 44 provides a flow measurement value for the heat transfer fluid downstream of the flow generator 34. The flow sensor 44 is, for example, a Coriolis flow meter. Alternatively, it is a pressure / temperature / pressure delta sensor at a calibrated orifice. In yet another embodiment, the sensor is replaced by a modeling module for the characteristics of the heat transfer fluid circuit, for example, via the flow rate / pressure drop relationship.

[0098] The calculation module 43 and the flow sensor 44 are connected to the inputs of a subtractor 45, to provide it respectively with the flow setpoint and the flow measurement value.

[0099] The subtractor 45 calculates the difference of the quantities it receives at input and provides at output a flow error to a regulator 46. The regulator 46 determines a flow generator command from the flow error.

[0100] The regulator 46 is connected at the output to the flow generator 34 and transmits to it the flow generator command to modulate its power, which allows the mass flow rate of the heat transfer fluid to be regulated.

[0101] It should be noted that the loop formed by elements 43, 44, 45 and 46 is identical in the three modes M1, M2 and M3. Only the mass flow setpoint of the heat transfer fluid changes depending on the mode.

[0102] The two control methods described above can be implemented simultaneously and independently because the dynamics of the physical phenomena, i.e., the flow rate evolution and the temperature evolution, are sufficiently distinct from each other. These controllers can be of the "PID" type or of the "state feedback" type. These two control methods can also be implemented simultaneously in the form of multivariable control.

[0103] It should be noted that in this mode, the bypass valve 36 of the second heat exchanger 32 located in the nozzle of the turbomachine is controlled in open loop in full opening, that is to say according to a maximum bypass of the second exchanger 32, in order to limit the heat losses in this exchanger.

[0104] Fig. 5 illustrates the second mode M2 ​​corresponding to the start-up phase of the turbomachine.

[0105] In this mode, the second turbomachine nozzle heat exchanger 32 produces little or no thermal power. The thermal power required for hydrogen vaporization is therefore supplied by the electric heater 35.

[0106] The following two regulations are therefore put in place in the second mode M2: on the one hand a closed loop regulation of the electric heater 35 and on the other hand a closed loop regulation of the flow generator 34.

[0107] First, an engine control module 50 determines a hydrogen temperature setpoint.

[0108] The temperature sensor 7 determines a measured temperature value of hydrogen at the injection point. The engine control module 50 and the temperature sensor 7 are connected to the inputs of a subtractor 51, to provide it respectively with the temperature setpoint and the measured temperature value.

[0109] The subtractor 51 calculates the difference between the input values ​​to produce a temperature error. The subtractor 51 is connected to the input of a controller 52. The subtractor 51 transmits the temperature error to the controller 52.

[0110] The controller 52 determines an electric heater command based on the temperature error. The controller 52 is connected at the output to the electric heater 35 and transmits the electric heater command to it to modulate its power, which allows the temperature of the heat transfer fluid and consequently the temperature of the hydrogen at the injection point to be regulated.

[0111] A gain determination module 53 determines the gains of the controller 52. The gain determination module 53 is connected to the controller 52 and transmits to it the gains it has determined. The gains of the controller 52 can be partially or totally predetermined, depending on the sensitivities of the system, based on the characteristics of the electric heater 35, in particular its efficiency, and the characteristics of the hydrogen, in particular its mass flow rate and its heat capacity at the first heat exchanger 31 of the hydrogen supply line.

[0112] Secondly, similarly to the first mode Ml, the calculation module 43 determines a heat transfer fluid flow setpoint. The heat transfer fluid flow setpoint is calculated "offline" so as to obtain internal temperatures of the heat transfer fluid circuit 3 within the acceptable limits of the system.

[0113] The flow sensor 44 provides a flow measurement value of the heat transfer fluid downstream of the flow generator 34. The flow sensor 44 is, for example, a A Coriolis flow meter. Alternatively, it is a pressure / temperature / pressure delta sensor at a calibrated orifice. In yet another variant, the sensor is replaced by a module for modeling the characteristics of the heat transfer fluid circuit, for example, via the flow rate / pressure drop relationship.

[0114] The calculation module 43 and the flow sensor 44 are connected to the inputs of the subtractor 45, to provide it respectively with the flow setpoint and the flow measurement value.

[0115] The subtractor 45 calculates the difference of the quantities it receives at input and provides at output a flow error to a controller 46. The controller 46 determines a flow generator command from the flow error.

[0116] The regulator 46 is connected at the output to the flow generator 34 and transmits to it the flow generator command to modulate its power, which allows the mass flow rate of the heat transfer fluid to be regulated.

[0117] The two control methods described above can be implemented simultaneously and independently because the dynamics of the physical phenomena, i.e., the flow rate evolution and the temperature evolution, are sufficiently distinct from each other. These controllers can be of the "PID" type or of the "state feedback" type. These two control methods can also be implemented simultaneously in the form of multivariable control.

[0118] It should be noted that in this mode, the bypass valve 36 of the second exchanger 32 located in the nozzle of the turbomachine is controlled in open loop at full opening, that is to say according to a maximum bypass of the second exchanger 32, in order to limit the heat losses in this exchanger.

[0119] Fig. 6 illustrates the third mode M3 corresponding to operating phases at the end of the turbomachine start-up and / or above the turbomachine idle speed, for example in transient acceleration regime.

[0120] In this mode, the second nozzle exchanger 32 of the turbomachine provides the thermal power necessary to heat the hydrogen to the target temperature.

[0121] Conventionally, temperature control involving a heat exchanger is achieved by modulating the flow rate of one of the passes (hot or cold) of this exchanger to vary its efficiency and therefore the outlet temperatures. However, the inventors have observed that, in the context of the invention, modulating the air flow rate in the hot pass (i.e., the primary flow of the turbomachine) is very complex to implement. Furthermore, modulating the flow rate of the heat transfer fluid in the cold pass results in few variations in the efficiency of the second heat exchanger 32 in the turbomachine nozzle, given the significant differences in mass flow rates between the passes (at most a few kg / s for the heat transfer fluid vs. several tens of kg / s for the air).

[0122] In the present invention, the inventors therefore propose to modulate the power of the second exchanger 32 in the nozzle of the turbomachine by diverting part of the total mass flow of the heat transfer fluid circuit 3 that can pass through the second exchanger 32 and then mixing the diverted flow and the flow actually passed through the second exchanger, the mixture then being reinjected into the heat transfer fluid circuit 3.

[0123] Furthermore, in the case of a transient turbomachine acceleration regime, there is a delay between a change in the thermal power required in the first heat exchanger 31 of the hydrogen supply line to vaporize the hydrogen and the change in the thermal power available in the second heat exchanger 32 located in the turbomachine nozzle. The inventors therefore propose to use the electric heater 35 to cover the additional thermal power requirements during the transient turbomachine acceleration regime.

[0124] The following two control systems are implemented in this third mode M3. These are closed-loop controls of the flow generator 34 and the bypass valve 36. The hydrogen injection temperature is regulated according to a temperature setpoint provided by the engine control unit by modulating the power supplied by the second heat exchanger 32 in the turbomachine nozzle via the bypass valve 36. The mass flow rate of the heat transfer fluid is regulated according to a heat transfer fluid flow setpoint by modulating the speed of the flow generator 34.

[0125] Furthermore, in the event of detection of a transient regime of the turbomachine, such as a transient acceleration regime, the electric heater 35 is controlled with a modulating electrical power. This electrical power is determined so as to be able to at least compensate for a thermal power deficit of the second heat exchanger 32 in the turbomachine nozzle during a transient regime of the turbomachine.

[0126] First, an engine control module 60 provides a hydrogen temperature setpoint.

[0127] The temperature sensor 7 provides a measured temperature value of hydrogen at the injection point. The engine control module 60 and the temperature sensor 7 are connected to the inputs of a subtractor 61, to provide it respectively with the temperature setpoint and the measured temperature value.

[0128] The subtractor 61 calculates the difference of the quantities it receives as input and provides as output a temperature error to a controller 62. The controller 62 determines a bypass valve control 36 from the temperature error.

[0129] The regulator 62 is connected at its output to the bypass valve 36 and transmits to it the bypass valve command to divert a portion of the total mass flow rate of the heat transfer fluid circuit 3 can pass through the second exchanger 32 and thus modulate the power of the second exchanger 32 in the nozzle of the turbomachine.

[0130] A gain determination module 63 determines the gains of the controller 62. The gain determination module 63 is connected to the controller 62 and transmits the gains it has determined to it. The gains of the controller 62 can be partially or totally predetermined, depending on the system sensitivities, including: - characteristics of the second exchanger 32 in the nozzle of the turbomachine, in particular its efficiency e; - characteristics of hydrogen, in particular its mass flow rate and its heat capacity at the level of the first exchanger of the hydrogen supply line; - characteristics of the heat transfer fluid, in particular its mass flow rate and its heat capacity at the level of the second exchanger 32 in the nozzle of the turbomachine; - the temperature difference at the inlet of the two passes of the second heat exchanger 32 in the turbomachine nozzle, i.e., between the air and the heat transfer fluid. The air temperature can be either measured in the turbomachine nozzle or determined by modeling based on other turbomachine measurements. The heat transfer fluid temperature is measured by the temperature sensor 38 located on the heat transfer fluid circuit upstream of the second heat exchanger 32 in the turbomachine nozzle.

[0131] Secondly, similarly to the two previous modes, the calculation module 43 determines a heat transfer fluid flow setpoint for closed-loop control of the heat transfer fluid flow rate. The heat transfer fluid flow setpoint is calculated "offline" so as to obtain internal temperatures of the heat transfer fluid circuit 3 within the acceptable limits of the system.

[0132] The flow sensor 44 provides a flow measurement value for the heat transfer fluid downstream of the flow generator 34. The flow sensor 44 is, for example, a Coriolis flow meter. Alternatively, it is a pressure / temperature / pressure delta sensor at a calibrated orifice. In yet another variant, the sensor is replaced by a modeling module for the characteristics of the heat transfer fluid circuit, for example, via the flow rate / pressure drop relationship.

[0133] The calculation module 43 and the flow sensor 44 are connected to the inputs of the subtractor 45, to provide it respectively with the flow setpoint and the flow measurement value.

[0134] The subtractor 45 calculates the difference of the quantities it receives at input and provides at output a flow error to a controller 46. The controller 46 determines a flow generator command from the flow error.

[0135] The regulator 46 is connected at the output to the flow generator 34 and transmits to it the flow generator command to modulate its power, which allows the mass flow rate of the heat transfer fluid to be regulated.

[0136] The two control methods described above can be implemented simultaneously and independently because the dynamics of the physical phenomena, i.e., the flow rate evolution and the temperature evolution, are sufficiently distinct from each other. These controllers can be of the "PID" type or of the "state feedback" type. These two control methods can also be implemented simultaneously in the form of multivariable control.

[0137] The motor control module 60 is also preferably connected to an electric heater setpoint determination module 47 35. The electric heater setpoint determination module 47 is connected to the electric heater 35.

[0138] When the engine control module 60 detects a transient acceleration of the turbomachine, it transmits a command to the electric heater setpoint control module 47. Module 47 then determines an electrical power setpoint and transmits it to the electric heater 35. This electrical power is adjustable and non-zero when a transient acceleration of the turbomachine is detected. The value of this electrical power is determined so as to at least compensate for the thermal power deficit of the second heat exchanger 32 in the turbomachine nozzle during a transient acceleration of the turbomachine. The effect of the thermal power input on the heat transfer fluid by the electric heater 35 is then measured by the heat transfer fluid temperature sensor 38 upstream of the second heat exchanger 32 in the turbomachine nozzle.This allows module 63 to adapt the gains of regulator 62 accordingly, and thus modulate the bypass valve 36 control signal that regulator 62 transmits to it.

[0139] Figure 7 illustrates a variant of the third mode M3 corresponding to phases of operation at the end of turbomachine start-up and / or above the turbomachine idle speed, for example during acceleration transients.

[0140] In this variant, the modifications compared to the embodiment of [Fig.6] are as follows.

[0141] The motor control module 60 is preferably connected to a diverter valve setpoint determination module 48. The module 48 is connected to the diverter valve 36.

[0142] The motor control module 60 and the temperature sensor 7 are connected to the inputs of the subtractor 61, to provide it respectively with the temperature setpoint and the temperature measurement value.

[0143] The subtractor 61 calculates the difference of the quantities it receives as input and provides as output a temperature error to a controller 64. The controller 64 determines an electric heater control 35 from the temperature error. The regulator 64 is connected at the output to the electric heater 35 and transmits the electric heater command to it to modulate its electrical power.

[0144] The regulator 64 can be of the "PID" type or of the "state feedback" type.

[0145] A gain determination module 63 determines the gains of the regulator 64. The The gain determination module 63 is connected to the regulator 64 and transmits the gains it has determined. The gains of the regulator 64 can be partially or totally predetermined, depending on the system sensitivities, including: - characteristics of the second exchanger 32 in the nozzle of the turbomachine, in particular its efficiency e; - characteristics of the electric heater 35; - characteristics of hydrogen, in particular its mass flow rate and its thermal capacity at the level of the first exchanger of the hydrogen supply line.

[0146] Furthermore, the flow regulation is identical to that previously described and is carried out by the regulator 46.

[0147] The two regulation methods described above are implemented simultaneously in a decoupled manner because the dynamics of the physical phenomena (flow rate evolution vs. temperature evolution) are sufficiently distinct from each other. These two regulation methods can also be implemented simultaneously in the form of multivariable regulation.

[0148] In this variant, when a transient acceleration regime of the turbomachine is detected by the engine control module 60, it commands the bypass valve setpoint determination module 48 to transmit to the bypass valve 36 of the second in-nozzle exchanger 32 of the turbomachine a full-close setpoint in order to maximize the thermal power supplied by the second in-nozzle exchanger 32 of the turbomachine.

[0149] The hydrogen temperature at the injection is then finely regulated via the modulation of the electrical power of the electric heater 35 via the regulator 64.

[0150] Figure 8 illustrates a variant of the heating circuit embodiment 3 shown in Figure 2. More specifically, Figure 8 represents the part of the heat transfer fluid circuit that is modified according to this variant.

[0151] In this variant, the heating circuit 3 comprises the elements described above. It also comprises a bypass valve 350 in parallel with the electric heater 35. The bypass valve 350 is, for example, a three-way valve or a two-way valve of the "On-Or-None" type.

[0152] Thus, the use of the electric heater 35 is selected according to the state of the bypass valve 350.

[0153] In the first mode M1 and the second mode M2, the bypass valve 350 is controlled so that all the heat transfer fluid flow passes through the electric heater 35. In the third mode M3, outside of transient conditions, particularly outside of acceleration transient conditions, the bypass valve 350 is preferably controlled so that all the heat transfer fluid flow is diverted from the electric heater 35.

[0154] This variant thus makes it possible to minimize the electrical consumption of the flow generator 34 by reducing pressure losses when the electric heater 35 is not in use.

[0155] Regardless of the embodiment, the transitions from one mode to another are conditioned in the following way.

[0156] A transition from the first mode M1 to the second mode M2 ​​can only be achieved when the hydrogen temperature sensor at the injection point 7 can detect the effect of the heat transfer fluid circuit 3 on the hydrogen temperature. This requires that a sufficient flow of hydrogen has circulated in the hydrogen supply line in the first mode M1 before transitioning to the second mode M2.

[0157] The transition from the first mode M1 to the second mode M2 ​​can be carried out according to one of the following two indicators: - From the initialization of the hydrogen flow in the hydrogen supply line, a timer is started. The transition occurs when the timer reaches a predetermined duration. This threshold duration takes into account the propagation time of a volume of heated hydrogen gas at the first heat exchanger 31 of the hydrogen supply line to the injection temperature sensor 7. It also takes into account the sensor's response time. - A temperature gradient at the injection point, measured by sensor 7, is determined. The transition occurs when this gradient exceeds a predetermined threshold for a predetermined duration; that is, the effect of heating or cooling at the hydrogen supply line heat exchanger is visible to temperature sensor 7.

[0158] The transition from the second mode M2 ​​to the third mode M3 can only occur when the thermal power that can be supplied by the second heat exchanger 32 in the turbomachine nozzle is sufficient. The thermal power d» supplied by the second heat exchanger 32 is estimated in real time from the following equation:

[0159] (|) = mf luide calo ' ^Fluide ca}o ' £ ' ( ^Airin " Tpiuide cato^)

[0160] Where: - ^Coolant flow rate is the mass flow rate of the heat transfer fluid in the heat transfer fluid circuit; - Cn is the heat capacity of the heat transfer fluid; calo fluid 1 1 F - e is the efficiency of the second exchanger 32 in the nozzle of the turbomachine; - TAirin is the temperature of the air at the inlet of the second exchanger 32 in the nozzle of the turbomachine. This temperature is estimated or measured and provided by the engine control module; - Tpiuide caloin is the temperature of the heat transfer fluid measured by the temperature sensor 38 located on the heat transfer fluid circuit upstream of the second exchanger 32 in the nozzle of the turbomachine.

[0161] When the thermal power supplied by the second exchanger 32 in the nozzle of the turbomachine is greater than that supplied by the electric heater 35, the transition indicator allows the transition from the second mode M2 ​​to the third mode M3.

[0162] It should be noted that during the transition from the second mode M2 ​​to the third mode M3, the electrical power supplied to the electric heater 35 is preferably gradually reduced, for example, according to a "ramp" or "first-order low-pass filter" profile. The residual effect of the electric heater 35 on the gains of the controller 62 is then measured and compensated via the cafo temperature measurement used in determining the gains by the module 63.

Claims

1.

2. Demands Temperature control device for a turbomachine hydrogen supply system, the hydrogen supply system comprising a pressurization unit (2) and a metering unit (5) arranged in series on a turbomachine hydrogen supply line, characterized in that the control device comprises a heat transfer fluid circuit (3) comprising: - a first heat exchanger (31) configured to be located between the pressurization unit (2) and the dosing unit (5) on the hydrogen supply line and configured to control the hydrogen temperature, - a second heat exchanger (32) configured to be located on a turbomachine nozzle and configured to extract heat from the air in the nozzle's primary intake, - a heat transfer fluid flow generator (34) and an electric heat transfer fluid heater (35), arranged in series between the first and second heat exchangers, - a bypass valve (36) located in parallel with the second heat exchanger (32) located in the nozzle of the turbomachine, - a control system configured for • control the flow generator (34) according to a heat transfer fluid flow setpoint and a heat transfer fluid flow measurement in the heat transfer fluid circuit (3), • detect a transient acceleration regime of the turbomachine, and in the event of detection of a transient acceleration regime of the turbomachine, control the electric heater (35) and the bypass valve (36) during said transient acceleration regime. A control device according to claim 1, wherein the control system comprises a motor control module (60) connected to an electric heater setpoint determination module (47), the electric heater setpoint determination module (47) being connected to the electric heater (35), the motor control module (60) being configured to detect a transient acceleration regime of the turbomachine and in case of detection of transient acceleration regime, configured to control the electric heater setpoint determination module (47) so that it transmits an operating setpoint to the electric heater (35).

3. Control device according to claim 2, wherein the electric heater setpoint determination module (47) is configured to control the electric heater (35), during a transient regime of the turbomachine, according to a modulating electrical power determined so as to be able to compensate for a thermal power deficit of the second exchanger (32).

4. Control device according to claim 2 or 3, wherein the control system includes a controller (62) connected to the bypass valve (36) and configured to control said valve as a function of a hydrogen temperature measurement in the turbomachine hydrogen supply line and a temperature setpoint provided by the engine control module (60).

5. Control device according to claim 1, wherein the control system comprises an engine control module (60) connected to a bypass valve setpoint determination module (48), the bypass valve setpoint determination module (48) being connected to the bypass valve (36), the engine control module (60) being configured to detect a transient acceleration regime of the turbomachine and, in the event of detection of a transient acceleration regime, configured to command the bypass valve setpoint determination module (48) to transmit to the bypass valve (36) of the second turbomachine nozzle exchanger (32) a fully closed setpoint so as to maximize the thermal power supplied by the second turbomachine nozzle exchanger (32).

6. Control device according to claim 5, wherein the control system includes a controller (64) connected to the electric heater (35) and configured to control said heater based on a temperature measurement of hydrogen in the turbomachine's hydrogen supply line and a temperature setpoint provided by the engine control module (60).

7. Hydrogen supply system for a turbomachine, characterized in that it comprises a control device according to any one of claims 1 to 6.

8. Turbomachine comprising injectors, characterized in that it comprises a hydrogen supply system according to claim 7 connected to said injectors.

9. Aircraft comprising a turbomachine according to claim 8.

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