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

Abstract

A temperature control device for the hydrogen supply of a turbomachine, comprising a heat transfer fluid circuit (3) including: a heat exchanger (31) on a hydrogen supply line of the turbomachine, a heat exchanger (32) in the nozzle of the turbomachine, in parallel with a first bypass valve (36), a flow generator (34) of heat transfer fluid and an electric heater (35) of heat transfer fluid, a third heat exchanger (80) connected to a hydraulic fluid circuit (8) connected to a hot source, to control its temperature, in parallel with a second bypass valve (81), a control system to control the flow generator, the electric heater, the first bypass valve, and the second bypass valve (81) according to a hydraulic fluid temperature setpoint in the hydraulic fluid circuit (8) and a hydraulic fluid temperature measurement in the hydraulic fluid circuit.Figure for the abridged version: figure 8.

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 contributing to the fight against climate change for several years now.

[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] This operation meets a precise objective of hydrogen temperature supplying the injectors while taking into account multiple system constraints, such as minimum and maximum temperature limits of the heating system.

[0015] Furthermore, on a turbomachine, a hot source is an element that requires cooling, such as the oil in the cooling system or the power electronic circuits for electrical machines. In a kerosene-powered turbomachine, it is known to use kerosene for this purpose, which then acts as a cold source in a hot source temperature control system.

[0016] However, for a turbomachine operating on hydrogen, the temperature of liquid hydrogen, on the order of 20K to 30K, is too low for use as a cold source.

[0017] There is therefore a need for hot source temperature regulation for a hydrogen-powered turbomachine. Description of the invention

[0018] 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 pressurization unit and a metering unit arranged in series on a hydrogen supply line to the turbomachine,

[0019] characterized in that the control device comprises a heat transfer fluid circuit including: - a first heat exchanger configured to be located between the pressurization unit and the dosing unit on the hydrogen supply line and configured to control the hydrogen temperature, - a second heat exchanger configured to be located in the turbomachine nozzle and configured to extract heat from the air in a primary jet of the nozzle, - a heat transfer fluid flow generator and an electric heat transfer fluid heater, arranged in series between the first and second heat exchangers, - a first bypass valve connected in parallel to the second exchanger, - a third heat exchanger located between the electric heater and the second heat exchanger, the third heat exchanger being configured to be connected to a hydraulic fluid circuit linked to a hot source, and configured to control the hot source temperature via the hydraulic fluid circuit, - a second bypass valve located between the electric heater and the second heat exchanger and connected in parallel to the third heat exchanger, - a control system configured for - to control the flow generator based on a setpoint for the heat transfer fluid flow rate and a measured flow rate of the heat transfer fluid in the heat transfer fluid circuit, - to control the electric heater based on a heat transfer fluid temperature setpoint and a heat transfer fluid temperature measurement in the heat transfer fluid circuit, or based on a hydrogen temperature setpoint and a hydrogen temperature measurement in the turbomachine's hydrogen supply line, - control the first bypass valve based on the hydrogen temperature setpoint and the hydrogen temperature measurement in the turbomachine's hydrogen supply line, and - control the second bypass valve based on a hydraulic fluid temperature setpoint in the hydraulic fluid circuit and a hydraulic fluid temperature measurement in the hydraulic fluid circuit downstream of the third exchanger.

[0020] Thanks to the invention, it is possible both to control the temperature of the hydrogen used to supply the turbomachine injectors and to control the temperature of at least one hot source. In other words, the heat transfer fluid has a dual purpose: on the one hand, to control the temperature of the hydrogen, and on the other hand, as a cold source for controlling the temperature of at least one hot source.

[0021] According to a preferred feature, the third exchanger, the second bypass valve and the hydraulic fluid circuit are duplicated for each hot source whose temperature is to be controlled.

[0022] According to a preferred feature, the control system includes a controller connected to the second bypass valve and configured to control said second valve as a function of the hydraulic fluid temperature measurement in the hydraulic circuit downstream of the third exchanger and the hydraulic fluid temperature setpoint in the hydraulic circuit provided by an engine control module.

[0023] According to a preferred feature, the regulator is duplicated for each hot source whose temperature is to be controlled.

[0024] According to a preferred feature, the control system includes a gain determination module connected to the controller and configured to determine the controller's gains based on a hydraulic fluid temperature measurement in the hydraulic circuit upstream of the third exchanger and a heat transfer fluid temperature measurement upstream of the second bypass valve and to transmit the determined gains to the controller.

[0025] The invention also relates to a hydrogen supply system for a turbomachine, characterized in that it comprises a control device as previously described.

[0026] The invention also relates to a turbomachine comprising injectors, characterized in that it comprises a hydrogen supply system as previously described and connected to said injectors.

[0027] The invention also relates to an aircraft comprising a turbomachine as previously described.

[0028] The hydrogen supply system of a turbomachine, the turbomachine, and the aircraft offer advantages similar to those previously described. Brief description of the drawings

[0029] 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:

[0030] [Fig.l] schematically illustrates a hydrogen supply system for a turbomachine;

[0031] [Fig.2] schematically illustrates one embodiment of a heating circuit included in the hydrogen supply system of a turbomachine;

[0032] [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;

[0033] [Fig.4] illustrates a first method of controlling the heat transfer fluid circuit, according to one embodiment;

[0034] [Fig.5] illustrates a second control method for the heat transfer fluid circuit, according to one embodiment;

[0035] [Fig.6] illustrates a third control method for the heat transfer fluid circuit, according to one embodiment;

[0036] [Fig.7] illustrates a variant embodiment of the heating circuit of [Fig.2];

[0037] [Fig.8] schematically illustrates an embodiment according to the invention of a circuit hot source temperature regulation included in the heating circuit of the [Fig.2];

[0038] [Fig.9] illustrates an embodiment according to the invention of a control method for the hot source temperature regulation circuit of [Fig.8].

[0039] 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.

[0040] The different parts represented in the figures are not necessarily shown on a uniform scale in order to make the figures more legible.

[0041] The different possibilities (variants and embodiments) should be understood as not being mutually exclusive and can be combined. Detailed description of the embodiments

[0042] 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, which can be included in the hydrogen supply system of [Fig. 1].

[0043] 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.

[0044] More specifically, [Fig. 1] represents the hydrogen supply line of the turbomachine. The hydrogen supply line comprises, in 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, particularly at low pressure, for example on the order of 2 bar to 3 bar, and at low temperatures, for example on an order of magnitude between 10K and 30K, for example 20K.

[0045] 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.

[0046] 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 greater than the sum of the pressure losses of the various equipment of the hydrogen supply system.

[0047] The pressurization device 2 can be a pump, in particular a centrifugal pump, or several pumps, in particular several centrifugal pumps, in series.

[0048] 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].

[0049] 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.

[0050] The metering element 5 can be a variable area metering valve or a pressure regulator coupled to a sonic neck.

[0051] 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.

[0052] The shut-off element 6 is, for example, an "on or off" type shut-off valve.

[0053] 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.

[0054] 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.

[0055] 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 injection, for example between 200 K and 350 K, gaseous hydrogen undergoes little temperature variation during isenthalpic compressions / expansions, that is to say, compressions / expansions caused by a pressure drop. For example, the pressure drop through the dosing unit 5, whose order of magnitude is several tens of bar, varies the temperature by only about 0.1 K.

[0056] Figure 2 illustrates one embodiment of a heating circuit 3. The circuit heating 3 includes the following elements.

[0057] 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.

[0058] The first heat exchanger 31 is designed to raise the temperature of the hydrogen, particularly liquid hydrogen. The first heat exchanger 31 thus controls the temperature of the hydrogen. This temperature increase ensures the evaporation of the hydrogen entering the heating circuit 3 into gaseous hydrogen, while maintaining a range of permissible temperatures for hydrogen combustion.

[0059] 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 be a tube or plate heat exchanger.

[0060] The heating circuit 3 also includes a second heat exchanger 32 located in the nozzle of the turbomachine and designed to extract heat from the air in the primary nozzle duct. 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 nozzle to the first heat exchanger 31 by the heat transfer fluid.

[0061] The second exchanger 32 can be a tube or plate exchanger using part or all of the primary flow from the turbomachine.

[0062] The heat transfer fluid can be supercritical nitrogen, supercritical carbon dioxide or helium.

[0063] 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.

[0064] The flow generator 34 can be a positive displacement or centrifugal pump.

[0065] 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 nozzle-type heat exchanger 32 does not supply enough. This point is detailed below.

[0066] The electric heater 35 can be an exchanger with continuously regulated or on-off regulated electrical power.

[0067] The heat transfer fluid circuit 3 also includes a bypass valve 36, or bypass, connected in parallel with the second exchanger 32 allowing an adjustable part of the heat transfer fluid flow passing through the second exchanger 32 to be diverted into a nozzle.

[0068] 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.

[0069] The temperature control of the hydrogen supply system of a turbomachine with the heat transfer fluid circuit is a three-control system: the flow rate of heat transfer fluid generated by the flow generator 34, the electrical power of the electric heater 35 and the section of the bypass valve 36.

[0070] 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.

[0071] The following operating phases of the turbomachine are considered: - Before starting the turbomachine: preparation and initialization of the turbomachine start-up; - During the start-up of the turbomachine: introduction and ignition of hydrogen in the combustion chamber of the turbomachine; - At the end of the start-up phase and above the turbomachine's idle speed. 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 a minimal load. The end of the start-up phase is the moment when the turbomachine reaches this operating state.

[0072] The corresponding control modes are: - The initialization, or preheating, of the heat transfer fluid circuit 3 during a preparation and initialization phase of the start-up of the turbomachine; - 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, during operating phases at the end of the turbomachine start-up and above the turbomachine idle speed.

[0073] The three operating modes include regulation of the flow of heat transfer fluid generated by the flow generator 34.

[0074] 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.

[0075] With reference to [Fig.3], the different control modes of the heat transfer fluid circuit and the possible transitions between these modes are described by a state diagram.

[0076] From a stopped state of the MO motor, when starting the motor, it is possible to switch to the first mode Ml which is the initialization, or preheating, mode of the heat transfer fluid circuit 3.

[0077] From the first mode M1, it is possible to switch to the 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.

[0078] From the second mode M2, it is possible to switch to the 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.

[0079] From the third mode M3, it is possible to return to the stopped state of the MO motor.

[0080] 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.

[0081] Fig. 4 illustrates the first mode Ml of initialization, or preheating, of the heat transfer fluid circuit 3.

[0082] 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.

[0083] 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.

[0084] The following two regulations are therefore put in place in the first mode Ml: 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.

[0085] First, a calculation module 40 determines a temperature setpoint for the heat transfer fluid. Preferably, the temperature setpoint for the heat transfer fluid is determined in an "offline" way, i.e. calculated in advance, so as to obtain approximately the desired temperature at the injection at the initialization of the hydrogen flow.

[0086] 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 sensor 37 are connected to the inputs of a subtractor 41, to provide it respectively with the temperature setpoint and the temperature measurement value.

[0087] 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.

[0088] 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.

[0089] A flow sensor 44 determines a flow rate measurement value of 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. Calibrated orifices are known to measure fluid flow rates. By knowing the pressure upstream and downstream of the orifice, it is possible to calculate the flow rate accurately using Bernoulli's principle and other fluidic equations. 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.

[0090] 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.

[0091] The subtractor 45 calculates the difference between the quantities it receives at input to determine a flow error. The subtractor 45 is connected to the input of a controller 46. The subtractor 45 provides the flow error to the controller 46. The controller 46 determines a flow generator command based on the flow error.

[0092] 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.

[0093] It should be noted that the loop formed by the elements 43, 44, 45 and 46 is identical in the three modes M1, M2 and M3 and that only the mass flow setpoint of the heat transfer fluid changes depending on the mode.

[0094] 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 one another. 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.

[0095] It should be noted that in this mode, the bypass valve 36 of the second exchanger 32 located in the nozzle 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.

[0096] Fig. 5 illustrates the second mode M2 ​​corresponding to the start-up phase of the turbomachine.

[0097] In this mode, the second nozzle-type heat exchanger 32 produces little or no thermal power. The thermal power required for the vaporization of hydrogen is therefore supplied by the electric heater 35.

[0098] 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.

[0099] First, an engine control module 50 determines a hydrogen temperature setpoint.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] A gain determination module 53 determines the gains of the regulator 52. The gain determination module 53 is connected to the regulator 52 and transmits to it the gains it has determined. The gains of the regulator 52 can be partially or totally predetermined, according to the sensitivities of the system, depending on the characteristics of the electric heater 35, in particular its efficiency, and the characteristics of hydrogen, in particular its mass flow rate and its thermal capacity at the level of the first exchanger 31 of the hydrogen supply line.

[0104] Secondly, similarly to the first mode M1, 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.

[0105] The flow sensor 44 determines a flow measurement value of 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.

[0106] 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.

[0107] The subtractor 45 calculates the difference between the input values ​​to determine a flow error. The subtractor 45 is connected to the input of the controller 46. The subtractor 45 provides the flow error to the controller 46. The controller 46 determines the flow generator control based on the flow error.

[0108] The regulator 46 is connected at the output to the flow generator 34 and applies the flow generator control to modulate its power, which allows the mass flow rate of the heat transfer fluid to be regulated.

[0109] 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.

[0110] It should be noted that in this mode, the bypass valve 36 of the second exchanger 32 located in the nozzle 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.

[0111] 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.

[0112] In this mode, the second turbomachine nozzle exchanger 32 provides the thermal power necessary to heat the hydrogen to the target temperature.

[0113] 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 exchanger 32 in the 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).

[0114] In the present invention, the inventors have succeeded in modulating the power of the second exchanger 32 in the nozzle of a 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.

[0115] The following two control mechanisms are therefore implemented in this third mode M3. These are closed-loop controls of the flow generator 34 and the bypass valve 36. The hydrogen temperature at injection 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 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.

[0116] First, an engine control module 60 determines a hydrogen temperature setpoint.

[0117] The temperature sensor 7 determines 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.

[0118] The subtractor 61 calculates the difference between the input values ​​to determine a temperature error. The subtractor 61 outputs the temperature error to a controller 62. The controller 62 determines a bypass valve command based on the temperature error. The controller 62 is connected at its output to the bypass valve 36 and transmits the bypass valve command to it to divert a portion of the total mass flow rate of the heat transfer fluid circuit 3 that can pass through the second heat exchanger 32, thus modulating the power of the second heat exchanger 32 in a nozzle configuration.

[0119] 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 nozzle, 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; - the temperature difference at the inlet of the two passes of the second nozzle-type heat exchanger 32, i.e., between the air and the heat transfer fluid. The air temperature can either be measured in the nozzle or determined by modeling based on other measurements from the turbomachine. The heat transfer fluid temperature is measured by the temperature sensor 38 located on the heat transfer fluid circuit upstream of the second nozzle-type heat exchanger 32.

[0120] 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.

[0121] The flow sensor 44 determines a flow rate measurement value of 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.

[0122] 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.

[0123] The subtractor 45 calculates the difference between the input values ​​to determine a flow error. The subtractor 45 is connected to the input of the controller 46. The subtractor 45 provides the flow error to the controller 46. The controller 46 determines a flow generator command based on the flow error.

[0124] 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.

[0125] 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.

[0126] In this third mode, the electric heater 35 is not used. It is therefore controlled in open loop at zero electrical power.

[0127] Figure 7 illustrates a variant of the heating circuit embodiment 3 shown in Figure 2. More specifically, Figure 7 represents the part of the heat transfer fluid circuit that is modified according to this variant.

[0128] 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.

[0129] Thus, the use of the electric heater 35 is selected according to the state of the bypass valve 350.

[0130] 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 regime, in particular outside of transient acceleration regime, the bypass valve 350 is preferably controlled so that all the heat transfer fluid flow is diverted from the electric heater 35.

[0131] 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.

[0132] Regardless of the embodiment, the transitions from one mode to another are conditioned in the following way.

[0133] 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.

[0134] 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 in takes into account the propagation time of a volume of heated gaseous hydrogen at the first exchanger 31 of the hydrogen supply line to the temperature sensor at the injection 7. It also takes into account the response time of the sensor. - 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, when the effect of heating or cooling at the hydrogen supply line heat exchanger is visible to temperature sensor 7.

[0135] 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 nozzle heat exchanger 32 is sufficient. The thermal power 0 supplied by the second heat exchanger 32 is estimated in real time from the following equation:

[0136] 0 — thFi ide calo'Cp (TAîr -T Calo fluid;} "He" Fluid cata M

[0137]

[0138]

[0139]

[0140] Or: - ^Fhddecalo is the mass flow rate of the heat transfer fluid in the heat transfer fluid circuit; - C» is the thermal capacity of the heat transfer fluid; PFluide ado 1 1 F - e is the efficiency of the second exchanger 32 in the nozzle; - is the temperature of the air entering the second exchanger 32 in nozzle. This temperature is estimated or measured and provided by the engine control module; - TFluide caloin is the temperature of the heat transfer fluid measured by the sensor temperature 38 located on the heat transfer fluid circuit upstream of the second exchanger 32 in the turbomachine nozzle. When the thermal power supplied by the second exchanger 32 in the nozzle 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. 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 progressively 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 fluid temperature measurement Tddoh, used in determining the gains by module 63. Figure 8 illustrates an embodiment according to the invention of a hot source temperature control circuit, included in the heating circuit 3.

[0141] A hot source is an element that requires cooling, such as the oil in the cooling system or the power electronic circuits for electrical machines.

[0142] The hot source temperature control circuit comprises the elements described below. The heating circuit 3 is modified as follows for a given hot source. It should be noted that the elements described below are duplicated for each hot source whose temperature is to be controlled.

[0143] With respect to the hot source considered, the heat transfer fluid of the heat transfer fluid circuit 3 is a cold source, that is to say an element capable of absorbing or dissipating heat to maintain or adjust the temperature of the hot source.

[0144] The heat transfer fluid in the heat transfer fluid circuit 3 is used in different temperature ranges, which allows its use as a cold source with respect to the given hot source. For example, in the case where the heat transfer fluid is nitrogen, the temperature of the heat transfer fluid between the outlet of the first heat exchanger 31 of the hydrogen supply line and the inlet of the second heat exchanger 32 varies between 150 K and 350 K.

[0145] A hydraulic circuit 8 of the considered hot source forms a loop between the hot source, not shown, and a third heat exchanger 80. Only the inlet and outlet paths of the hydraulic circuit 8 in the third heat exchanger 80 are shown to simplify the figure.

[0146] The third heat exchanger 80 is connected between the electric heater 35 and the assembly comprising the second heat exchanger 32 and the bypass valve 36. The third heat exchanger 80 is a heat exchanger with the hydraulic circuit 8. It allows the hot source temperature to be controlled via the hydraulic circuit 8. The third heat exchanger 80 is, for example, a tube or plate heat exchanger.

[0147] A second bypass valve 81 is connected in parallel with the third heat exchanger 80. The second bypass valve 81 allows modulation of the fraction of the total mass flow of heat transfer fluid passing through the third heat exchanger 80. The second bypass valve 81 is, for example, a two-way valve or a three-way valve.

[0148] A temperature sensor 82 is located on the heat transfer fluid circuit 3, upstream of the third heat exchanger 80 and the second bypass valve 81. Two temperature sensors 83 and 84 are located on the hydraulic circuit 8 of the hot source, respectively upstream and downstream of the third heat exchanger 80. Alternatively, one or more of the temperature sensors 82, 83 and 84 may be replaced by a temperature estimation module per model.

[0149] If the hydraulic fluid of the hot source's hydraulic circuit 8 is the "limiting fluid" of the heat exchange that occurs in the third heat exchanger 80, the The temperature of the hydraulic fluid in the hydraulic circuit of the hot source at the outlet of the third heat exchanger 80 varies according to the equation:

[0150] Hot spring m[ ~ Hot spring jn " ^80 ' ( Hot spring in " Cold spring.* )

[0151] Where:

[0152] T Hot source mtt is the temperature of the hydraulic fluid in the hydraulic circuit of the hot source at the outlet of the third heat exchanger 80,

[0153] T hot source in^ the temperature of the hydraulic fluid of the hydraulic circuit of the hot source at the inlet of the third exchanger 80,

[0154] T Cold source.* is the temperature of the heat transfer fluid in the heat transfer fluid circuit 3 upstream of the third interchange 80,

[0155] ^80 is the efficiency of the third interchange 80 whose mapping varies according to: - of the mass flow rate ^Coolant fluid and of the heat capacity C» of the 'Coolant fluid heat transfer fluid at the inlet of the third exchanger 80; - of the mass flow rate ^Hot source and of the thermal capacity Cp Hot source of the fluid in the hydraulic circuit of the hot source at the inlet of the third exchanger 80.

[0156] By "limiting fluid", we mean here, in the case of a heat exchange between two different fluids having different thermal capacities, the fluid which has the lowest product (mass flow rate x thermal capacity).

[0157] Figure 9 illustrates an embodiment according to the invention of regulating the hydraulic fluid temperature of the hydraulic circuit 8 of the hot source at the outlet of the third exchanger 80. It should be noted that the elements described below are duplicated for each hot source whose temperature is to be controlled.

[0158] A motor control module 90 determines a hydraulic fluid temperature setpoint for the hot source hydraulic circuit.

[0159] The temperature sensor 84 determines a temperature measurement value of the hydraulic fluid in the hydraulic circuit of the hot source at the outlet of the third heat exchanger 80. The motor control module 90 and the temperature sensor 84 are connected to the inputs of a subtractor 91, to provide it respectively with the temperature setpoint and the temperature measurement value.

[0160] The subtractor 91 calculates the difference between the input values ​​to determine a temperature error. The subtractor 91 outputs the temperature error to a controller 92. The controller 92 can be of the "PID" type or of the "state feedback" type. The controller 92 determines a bypass valve 81 command based on the temperature error. The controller 92 is connected at its output to the bypass valve 81 and transmits the bypass valve command to it. to divert part of the total flow of the heat transfer fluid that can pass through the third exchanger 80 and thus modulate the power of the third exchanger 80.

[0161] A gain determination module 93 determines the gains of the regulator 92. The gain determination module 93 is connected to the regulator 92 and transmits the gains it determines to it. The gains of the regulator 92 can be partially or totally predetermined, according to: - the efficiency Sgi of the third exchanger 81; - the temperature T hot source^ of the hydraulic fluid of the hot source in upstream of the third interchange 81; - the temperature T of the cold source of the heat transfer fluid upstream of the third interchange 81.

[0162] As already mentioned, the temperatures can be values ​​measured by sensors 82, 83 and 84 or modeled values.

[0163] The regulator 92 can be grouped with the regulator 62 described above for the third mode M3 of control of the heat transfer fluid circuit.

[0164] Adding a hot source temperature control circuit to the heat transfer fluid circuit 3 reduces the thermal power required from the second turbomachine nozzle heat exchanger 32 to achieve the desired hydrogen injection temperature. Its addition is transparent to the third control mode M3 of the heat transfer fluid circuit because it is taken into account in the gain determination module 63 via the temperature sensor 38 located on the heat transfer fluid circuit upstream of the second nozzle heat exchanger 32.

Claims

1. 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 in the nozzle of the turbomachine and configured to extract heat from the air in a primary jet of the nozzle, - 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 first bypass valve (36) connected in parallel with the second exchanger, - a third heat exchanger (80) located between the electric heater (35) and the second heat exchanger (32), the third heat exchanger being configured to be connected to a hydraulic fluid circuit (8) connected to a hot source, and configured to control the hot source temperature via the hydraulic fluid circuit (8), - a second bypass valve (81) located between the electric heater (35) and the second heat exchanger (32) and connected in parallel to the third heat exchanger (80), - a control system configured for - to 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, - control the electric heater (35) according to a setpoint temperature of the heat transfer fluid and a - temperature measurement of heat transfer fluid in the heat transfer fluid circuit, or as a function of a hydrogen temperature setpoint and a hydrogen temperature measurement in the turbomachine's hydrogen supply line, - control the first bypass valve (36) as a function of the hydrogen temperature setpoint and the hydrogen temperature measurement in the turbomachine's hydrogen supply line, and - control the second bypass valve (81) as a function of a hydraulic fluid temperature setpoint in the hydraulic fluid circuit (8) and a hydraulic fluid temperature measurement in the hydraulic fluid circuit (8) downstream of the third exchanger (80).

2. Control device according to claim 1, wherein the third exchanger (80), the second bypass valve (81) and the hydraulic fluid circuit (8) are duplicated for each hot source whose temperature is to be controlled.

3. Control device according to claim 1 or 2, wherein the control system comprises a controller (92) connected to the second bypass valve (81) and configured to control said second valve as a function of the hydraulic fluid temperature measurement in the hydraulic circuit (8) downstream of the third exchanger (80) and the hydraulic fluid temperature setpoint in the hydraulic circuit (8) provided by a motor control module (60).

4. Control device according to claim 3, wherein the regulator (92) is duplicated for each hot source whose temperature is to be controlled.

5. A control device according to claim 3 or 4, wherein the control system comprises a gain determination module (93) connected to the controller (92) and configured to determine the gains of the controller (91) as a function of a hydraulic fluid temperature measurement in the hydraulic circuit (8) upstream of the third heat exchanger (80) and a heat transfer fluid temperature measurement

6.

7.

8.

9. upstream of the second bypass valve (81) and to transmit the determined gains to the regulator. Control device according to claim 5, wherein the gain determination module (93) is duplicated for each hot source whose temperature is to be controlled. Hydrogen supply system for a turbomachine, characterized in that it comprises a control device according to any one of claims 1 to 6. Turbomachine comprising injectors, characterized in that it comprises a hydrogen supply system according to claim 7 connected to said injectors. Aircraft comprising a turbomachine according to claim 8.