Temperature control system for a heat transfer fluid in a circulation loop, temperature control method
Patent Information
- Application Number
- FR2022003890
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-04-26
- Publication Date
- 2025-03-07
- Estimated Expiration
- 2042-04-26
Smart Images
Figure 00000019_0000 
Figure 00000020_0000
Abstract
Description
Title of the invention: System for controlling the temperature of a heat transfer fluid in a circulation loop, temperature control method Technical field
[0001] The present invention relates to the field of aircraft comprising a fluid stored in a cryogenic tank, for example fuel supplying a turbomachine.
[0002] It is known to store a fluid, for example fuel such as hydrogen, in liquid form to limit the size and mass of the aircraft tanks. For example, the fuel is stored at a temperature of the order of -253 to -251°C (20 to 22 Kelvins) in a cryogenic tank of the aircraft.
[0003] In this example, in order to be injected into the combustion chamber of a turbomachine, the fuel must be conditioned, i.e. pressurized and heated, in order to allow optimal combustion. Conditioning is for example necessary to reduce the risk of icing / solidification of the water vapor contained in the air circulating in the turbomachine, in particular, at the fuel injectors of the turbomachine.
[0004] With reference to [Fig. 1], there is shown a conditioning system SC AA comprising a fuel circuit CQ connected at the inlet to a cryogenic tank R and at the outlet to the combustion chamber of a turbomachine M. The conditioning system SCAA comprises a mechanical pump P for driving a flow of fuel Qc from upstream to downstream in the fuel circuit CQ. In a known manner, the aircraft comprises an engine enclosure EN-M (for example a nacelle) and a tank enclosure EN-R, separate and remote from the engine enclosure EN-M. The cryogenic tank R is mounted in the tank enclosure EN-R and the turbomachine M is mounted in the engine enclosure EN-M.
[0005] The SCAA conditioning system also comprises a temperature control system 101 of a heat transfer fluid F which provides calories to the fuel flow Qc in order to heat it so that it can be injected into the turbomachine M with an optimal temperature and pressure.
[0006] In the prior art, for example, patent application FR2005628A1 discloses a temperature control system 101, also shown in [Fig. 1], which comprises a circulation loop 102 for the heat transfer fluid F and a mechanical recirculation pump 103 for driving the heat transfer fluid F in motion in the circulation loop 102. In the control system 101 described in document FR2005628A1, the heat transfer fluid F extracts calories from hot sources Cm available on board the aircraft (for example the heat from the lubricating oil of the turbomachine M, the calories at the turbine outlet, heat from the nozzle), via an engine heat exchanger 104 mounted on the circulation loop 102 in the assembly enclosure EN-M. The temperature control system 101 also comprises a tank heat exchanger 105 for heating the fuel flow Qc of the SCAA conditioning system from the calories transferred by the heat transfer fluid F.
[0007] In practice, the heat sources Cm present in the engine enclosure EN-M make it possible to heat the heat transfer fluid F via the engine exchanger 104 from a first temperature T1 to a second temperature T2. The heat transfer fluid F then circulates at the temperature T2 in the circulation loop 102 to the tank exchanger 105 to heat the fuel flow Qc at the outlet of the mechanical pump P, therefore in the tank enclosure EN-R. In an embodiment not shown, the architecture described in patent FR2005628A1 also comprises a heat exchanger mounted in the tank enclosure EN-R to heat the heat transfer fluid F once again by means of the heat sources present in the tank enclosure EN-R, such as the air at the cabin outlet or the thermal discharges from the electrical / electronic components on board for example.
[0008] However, in a known manner, in such a control system 101, the temperature of the heat transfer fluid F must not exceed a predetermined temperature range. In practice, the temperature T2 of the heat transfer fluid F at the outlet of the engine enclosure EN-M must be lower than a maximum operating temperature Tmax, in order to be able to convey the heat transfer fluid F as close as possible to the tank R without risking damage to the structure of the aircraft through which the circulation loop 102 passes, such as the wings of the aircraft for example. On the other hand, the temperature T1 of the heat transfer fluid F at the inlet of the engine enclosure EN-M must be higher than a minimum operating temperature Tmin, in order to avoid any risk of icing of the heat sources Cm in the engine exchanger 104. In other words, the control of the temperature in the circulation loop 102 is highly constrained.
[0009] To limit the maximum temperature of the heat transfer fluid F at the outlet of the engine exchanger 104, it is known to increase the circulation flow rate of the heat transfer fluid F in the circulation loop 102, which has many drawbacks. Indeed, the mass and size of the piping of the circulation loop 102 are very significant, which is not desirable in an aircraft. In addition, the aerothermal performance of the heat exchangers is limited, which increases the distribution defects in the heat exchangers. The mechanical pump is also forced to operate at a higher flow rate, which increases its electrical consumption.
[0010] The invention thus aims to eliminate at least some of these drawbacks by proposing a new system for controlling the temperature of the heat transfer fluid in the circulation loop allowing heating which is efficient and reliable, without limiting the temperature range of the heat transfer fluid. PRESENTATION OF THE INVENTION
[0011] The invention relates to a system for controlling the temperature of a heat transfer fluid configured to transfer calories to a fluid to be heated, the fluid to be heated coming from a cryogenic tank in which it is stored at an initial temperature and configured to be conveyed to an engine via a fluid circuit, the cryogenic tank being mounted in a tank enclosure, the engine being mounted in a engine enclosure separate from the tank enclosure, the control system comprising: • a heat transfer fluid circulation loop extending both in the tank enclosure and in the engine enclosure, the circulation loop comprising: • a motor branch extending in the motor enclosure between a motor inlet point and a motor outlet point, the heat transfer fluid circulating from upstream to downstream between the motor inlet point and the motor outlet point, the heat transfer fluid having a first temperature at the motor inlet point, • a tank branch extending into the tank enclosure between a tank inlet point and a tank outlet point, the heat transfer fluid circulating from upstream to downstream between the tank inlet point and the tank outlet point, the engine outlet point being fluidically connected to the tank inlet point, the tank outlet point being fluidically connected to the engine inlet point, • at least one mechanical pump configured to circulate the heat transfer fluid in the circulation loop, • at least one first engine exchanger, mounted on the engine branch, configured to heat the heat transfer fluid to a third temperature higher than the first temperature, from calories transferred by at least one hot fluid available in the engine enclosure, the third temperature being higher than a maximum operating temperature, • at least one first tank exchanger, mounted on the tank branch, configured to heat the fluid to be heated from calories transferred by the heat transfer fluid to a primary temperature, • at least one regenerative heat exchanger, mounted on the engine branch, the regenerative heat exchanger being configured to heat the heat transfer fluid to a second temperature higher than the first temperature and lower than the third temperature, the second temperature being higher than a minimum operating temperature, the regenerative heat exchanger being configured to transfer calories from the heat transfer fluid circulating downstream of the first engine exchanger at the third temperature to the heat transfer fluid circulating upstream of the first engine exchanger at the first temperature, so as to allow the heat transfer fluid to be heated in the first engine exchanger to a temperature higher than the maximum operating temperature and to be cooled before leaving the engine enclosure to a temperature lower than the maximum operating temperature.
[0012] The control system according to the invention allows the heat transfer fluid to enter the engine enclosure at a temperature lower than the minimum operating temperature. Greater cooling allows the heat transfer fluid to transfer more calories to the fluid to be heated in the first reservoir exchanger, allowing the fluid to be heated to a greater extent. Since the heat transfer fluid is advantageously heated by the regenerative heat exchanger before entering the first engine exchanger, the circulation loop does not present any risk of icing the heat source(s) in the first engine exchanger.
[0013] Advantageously, the heat transfer fluid can also be heated by the first engine exchanger to a temperature above the maximum operating temperature, which makes it possible not to increase the circulation flow rate of the heat transfer fluid in the first engine exchanger. A limited flow rate advantageously makes it possible to limit the mass and size of the piping in the circulation loop, since the latter does not need to be reinforced to withstand particularly high flow rates. A limited flow rate also makes it possible to optimize the aerothermal performance of the heat exchangers mounted on the circulation loop, which makes it possible to limit the risks of faulty distribution of the fluids in the heat exchangers. In addition, the mechanical pump is not forced to operate at a particularly high flow rate, which makes it possible to limit its wear and its electrical consumption.
[0014] In a preferred embodiment, the minimum operating temperature corresponds to the minimum temperature at the inlet of the heat exchangers in which hot fluids from hot sources external to the control system circulate.
[0015] In one embodiment, the minimum operating temperature is between 2°C (275K) and 90°C (363K). Preferably, the minimum operating temperature operating temperature is equal to 2°C (275K).
[0016] In one embodiment, the maximum operating temperature is between 127°C (400K) and 227°C (500K). Preferably, the maximum operating temperature is 227°C (500K).
[0017] In one embodiment, the first temperature of the heat transfer fluid is between -123°C (150K) and -23°C (250K). The heat transfer fluid can thus be at a low temperature, without risking icing the heat sources in the first engine exchanger. For example, the heat transfer fluid can be at a temperature lower than 2°C (275K) at the outlet of the first tank exchanger. The heat transfer fluid can thus transfer more calories to the fluid to be heated in the first tank exchanger than in the control systems of the prior art, in which the heat transfer fluid had to be at a temperature higher than 2°C (275K) at the outlet of the first tank exchanger.
[0018] Preferably, the second temperature of the heat transfer fluid is between 2°C (275K) and 90°C (363K). The temperature of the heat transfer fluid is thus greater than 2°C (275K) when entering the first engine exchanger, which makes it possible to limit any risk of icing of the heat sources.
[0019] In a preferred embodiment, the third temperature of the heat transfer fluid is between 227°C (500K) and 377°C (650K), which makes it possible to reduce the circulation flow rate of the heat transfer fluid, thus allowing the use of less heavy and less bulky piping.
[0020] Preferably, the fourth temperature of the heat transfer fluid is between 127°C (400K) and 227°C (500K). The temperature of the heat transfer fluid is thus lower than the maximum operating temperature when leaving the engine enclosure. This allows the heat transfer fluid to circulate between the engine enclosure and the tank enclosure, for example in the structure of an aircraft (for example in the wings) without this presenting any risk of damage. In addition, the transport of the fluid does not need to be carried out in special pipes to withstand high temperatures, pipes which would have a significant mass and bulk.
[0021] In one embodiment, the control system comprises at least one second tank exchanger, mounted on the tank branch, the second tank exchanger being configured to heat the heat transfer fluid from calories transferred by at least one hot fluid available in the tank enclosure, the second tank exchanger being configured to heat the heat transfer fluid from a fifth temperature reached at the outlet of the first tank exchanger to the first temperature. Such a second tank exchanger makes it possible to use heat available on board the aircraft and thus to limit the size and the size of an exchanger in the turbomachine. The second tank exchanger mounted between the first tank exchanger and the tank outlet point also makes it possible to locally lower the temperature of the heat transfer fluid in the first tank exchanger to a temperature below the minimum operating temperature Tmin since the latter will then be reheated, making it possible to further lower the heat transfer fluid flow rate.
[0022] In one embodiment, the control system comprises at least one second engine exchanger mounted on the engine branch upstream of the first engine exchanger, the second engine exchanger being configured to heat the fluid to be heated from the heat transfer fluid to a secondary temperature higher than the primary temperature. Such an embodiment allows heating of the fluid to be heated in two stages. In a first stage, the fluid to be heated is heated in the first reservoir exchanger to the primary temperature, ensuring the best compromise between simplicity and safety of implementation of the circuit. In a second stage, the fluid to be heated is heated in the second engine exchanger to the secondary temperature sufficiently high to allow, for example, the injection of fuel into the turbomachine to supply it.
[0023] In such an embodiment, the heat transfer fluid can also be heated in the first engine exchanger to a temperature higher than the third temperature since the latter will transfer a first part of its calories to the heat transfer fluid circulating upstream of the first engine exchanger in the regenerative heat exchanger, and a second part of its calories to the fluid to be heated in the second engine exchanger, before leaving the engine enclosure.
[0024] The invention also relates to a fuel conditioning system configured to supply an aircraft turbomachine with fuel from a cryogenic tank, the conditioning system extending into the tank enclosure and into the engine enclosure, the cryogenic tank being mounted in the tank enclosure and the turbomachine being mounted in the engine enclosure, the conditioning system comprising: • a fuel circuit connected at the inlet to the cryogenic tank and at the outlet to the turbomachine, a flow of fuel circulating from upstream to downstream in the fuel circuit, • at least one mechanical pump configured to circulate the flow of fuel from the cryogenic tank from upstream to downstream in the fuel circuit, and • a temperature control system as described previously transferring calories to the fluid to be heated.
[0025] In a first embodiment, the primary temperature of the fuel flow at the outlet of the first tank exchanger is between -173°C (100K) and -73°C (200K), which makes it possible to ensure that the fuel is in a gaseous state at the outlet of the first tank exchanger, making it possible to limit the use of specific pipes which would have particular thermal insulation and would therefore be heavier, more cumbersome and more expensive.
[0026] In a second embodiment, the primary temperature of the fuel flow leaving the first engine exchanger is between -73°C (200K) and 27°C (300K), corresponding to the injection temperature of the fuel into the combustion chamber of the turbomachine, which makes it possible to limit the risk of icing of the injectors mounted in the combustion chamber.
[0027] The invention also relates to an aircraft comprising a cryogenic tank, a turbomachine and a conditioning system as described previously for supplying the turbomachine.
[0028] Finally, the invention relates to a method for controlling the temperature of a heat transfer fluid by means of the control system as described above, the heat transfer fluid being initially at the engine entry point at a first temperature, the method comprising the steps of: • preheat the heat transfer fluid upstream of the first engine exchanger, in the regenerative heat exchanger, to a second temperature higher than the first temperature and the minimum operating temperature, • heat the heat transfer fluid in the first engine exchanger to a third temperature higher than the second temperature and higher than the maximum operating temperature, • cool the heat transfer fluid downstream of the first engine exchanger, in the regenerative heat exchanger, to a fourth temperature lower than the third temperature and lower than the maximum operating temperature.
[0029] In one embodiment, the first temperature is below the minimum operating temperature. PRESENTATION OF FIGURES
[0030] The invention will be better understood on reading the description which follows, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.
[0031] [Fig.l] is a schematic representation of a conditioning system comprising a control system according to the prior art.
[0032] [Fig.2] is a schematic representation of a packaging system comprising a control system according to one embodiment of the invention.
[0033] [Fig. 3] is a schematic representation of a control system according to a second embodiment of the invention.
[0034] [Fig.4] is a schematic representation of a control system according to a third embodiment of the invention.
[0035] It should be noted that the figures set out the invention in detail to implement the invention, said figures can of course be used to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION
[0036] With reference to [Fig.2], a conditioning system SC for a fluid to be heated Q from a cryogenic tank R is shown. In this example, the fluid to be heated Q is stored in the cryogenic tank R at an initial temperature Ti of the order of -253 to -251°C (20 to 22 Kelvins). At this temperature, the fluid to be heated Q is liquid.
[0037] In this example, the fluid to be heated Q is fuel to power an engine, in particular in this example an aircraft turbomachine M. It goes without saying that the fluid to be heated Q could be different, in particular the oxidant (oxygen) or the inert service gases (nitrogen, CO2). In this example, the turbomachine M is configured to provide propulsion for the aircraft, in particular, by driving at least one propulsion member. Finally, in this example, the fuel is liquid hydrogen, but it goes without saying that the invention applies to other types of fuel, for example, liquid methane or liquefied natural gas.
[0038] As shown in [Fig.2], the cryogenic tank R is mounted in a tank enclosure EN-R and the engine M is mounted in a motor enclosure EN-M, separate and remote from the tank enclosure EN-R. The conditioning system SC extends both in the motor enclosure EN-M and in the tank enclosure EN-R.
[0039] In this example, the conditioning system SC comprises a fuel circuit CQ connected at the inlet to the cryogenic tank R and at the outlet to the turbomachine M, and a mechanical pump P configured to circulate a flow of fuel Q to be heated from the cryogenic tank R from upstream to downstream in the fuel circuit CQ. It goes without saying that the conditioning system SC could comprise a different number of mechanical pumps P, in particular a number greater than one mechanical pump P.
[0040] The conditioning system SC also comprises a system 1 for controlling the temperature of a heat transfer fluid F according to the invention, configured to transfer calories to the fuel flow Q so as to heat it so that it can power the turbomachine M.
[0041] According to the invention, still with reference to [Fig. 2], the control system 1 comprises a circulation loop 2 of the heat transfer fluid F extending both in the reservoir enclosure EN-R and in the engine enclosure EN-M. The circulation loop 2 is configured to operate at a temperature higher than the minimum operating temperature Tmin at the inlet of the hot source heat exchangers, to avoid icing the external hot sources in the heat exchangers, as will be described in more detail later. By the expression "configured to operate at a temperature", it is meant that the fluids (fluid to be heated Q, heat transfer fluid F, hot fluids, etc.) circulate at a temperature higher than the minimum operating temperature Tmin.Similarly, circulation loop 2 is configured to operate at a temperature lower than a maximum operating temperature Tmax at the outlet of the engine enclosure EN-M, to avoid any risk of damage to the structure of the aircraft during the circulation of the heat transfer fluid F between the engine enclosure EN-M and the tank enclosure EN-R.
[0042] In this example, the minimum operating temperature Tmin is of the order of 2°C (275K). Similarly, in this example, the maximum operating temperature Tmax is of the order of 227°C (500K).
[0043] According to the invention, the circulation loop 2 comprises a motor branch 21, extending in the motor enclosure EN-M between a motor inlet point Pim and a motor outlet point P2m, and a reservoir branch 22, extending in the reservoir enclosure EN-R between a reservoir inlet point Plr and a reservoir outlet point P2r. The motor outlet point P2m is fluidically connected to the reservoir inlet point Plr and the reservoir outlet point P2r is fluidically connected to the motor inlet point Pim, so as to allow the continuous circulation of the heat transfer fluid F in the circulation loop 2.
[0044] The heat transfer fluid F circulates in the engine branch 21 from upstream to downstream between the engine inlet point Pim and the engine outlet point P2m, and in the reservoir branch 22 from upstream to downstream between the reservoir inlet point Plr and the reservoir outlet point P2r.
[0045] The heat transfer fluid F has a first temperature TL at the engine inlet point Pim. According to the invention, the first temperature Tl may be either lower or higher than the minimum operating temperature Tmin at the inlet of the engine enclosure EN-M, as will be described in more detail below. In this example, the first temperature Tl is between -123 and -23°C (150 and 250 K).
[0046] Still with reference to [Fig.2], the control system 1 comprises a pump mechanical pump 3 configured to circulate the heat transfer fluid F in the circulation loop 2. It goes without saying that the circulation loop 2 could comprise a different number of mechanical pumps 3.
[0047] Preferably, the mechanical pump 3 is positioned in the circulation loop 2 so as to receive the heat transfer fluid F having the minimum temperature, so as to take advantage of the maximum density of the heat transfer fluid F, which makes it possible to pump the same mass flow rate at a lower energy cost. In this example, the mechanical pump 3 is mounted in the engine enclosure EN-M, as shown in [Fig.2]. It goes without saying that the mechanical pump 3 could just as easily be mounted in the tank enclosure EN-R, as shown in [Fig.3].
[0048] According to the invention, the control system 1 comprises a first engine exchanger 41 and a first tank exchanger 51, mounted on the circulation loop 2.
[0049] The first engine exchanger 41 is mounted in the engine enclosure EN-M on the engine branch 21. The first engine exchanger 41 is configured to heat the heat transfer fluid F from calories transferred by one or more hot fluid(s) Cm available in the engine enclosure EN-M, for example the heat from the lubricating oil of the turbomachine M, the calories at the turbine outlet, the heat from the nozzle, etc.
[0050] The first engine exchanger 41 is configured to heat the heat transfer fluid F to a third temperature T3 higher than the first temperature TL. More precisely, according to the invention, the third temperature T3 is higher than the maximum operating temperature Tmax, in this example of the order of 227°C (500K). In particular, in this example, the third temperature T3 of the heat transfer fluid F at the outlet of the first engine exchanger 41 is between 227°C (500K) and 377°C (650K), which advantageously makes it possible to limit the circulation flow rate of the heat transfer fluid F in the circulation loop 2.
[0051] The first tank exchanger 51 is mounted in the tank enclosure EN-R on the tank branch 22. The first tank exchanger 51 is configured to heat the fluid to be heated Q, in this example the fuel flow, from calories transferred by the heat transfer fluid F.
[0052] The first tank exchanger 51 is configured to heat the fuel flow to a primary temperature Tp higher than the initial temperature Ti. In this example, the primary temperature Tp at the outlet of the first tank exchanger 51 is between -73°C (200K) and 27°C (300K). Such a temperature makes it possible, for example, to limit any risk of icing of the water vapor contained in the air in contact with the fuel injectors in the combustion chamber of the turbomachine M.
[0053] EXrAccording to the invention, the control system 1 comprises a heat exchanger re EX generator mounted on the engine branch 21. For the sake of brevity, such an exchanger will hereinafter be referred to as an “EXr regenerative exchanger”. The EXr regenerative exchanger is configured to heat the heat transfer fluid F directly upstream of the first engine exchanger 41 by the heat transfer fluid F directly downstream of the first engine exchanger 41.
[0054] More precisely, the regenerative exchanger EXr is configured to heat the heat transfer fluid F circulating upstream of the first engine exchanger 41, initially at the first temperature T1, up to a second temperature T2, from calories transferred by the heat transfer fluid F which circulates downstream of the first engine exchanger 41, initially at the third temperature T3. According to the invention, the second temperature T2 is higher than the minimum operating temperature Tmin, the second temperature T2 being higher than the first temperature T1 and lower than the third temperature T3.
[0055] Incidentally, downstream of the first engine exchanger 41, the regenerative exchanger EXr is configured to lower the temperature of the heat transfer fluid F initially at the third temperature T3, down to a fourth temperature T4 lower than the maximum operating temperature Tmax.
[0056] In other words, the regenerative exchanger EXr allows the heat transfer fluid F to be heated in the first engine exchanger 41 to a temperature higher than the maximum operating temperature Tmax and to be cooled before leaving the engine enclosure EN-M to a temperature lower than the maximum operating temperature Tmax. The temperature of the heat transfer fluid F is thus not limited in the engine enclosure EN-M, which makes it possible to limit its flow rate, making it possible to limit the diameter, mass and size of the piping in the circulation loop 2.
[0057] Thus the temperature T1 can be lower than the minimum operating temperature Tmin at the engine entry point Pim since the temperature of the heat transfer fluid F will be heated to the second temperature T2 before its entry into the first engine exchanger 41, the hot sources Cm thus do not risk icing in the first engine exchanger 4L.
[0058] In one embodiment, the second temperature T2 of the heat transfer fluid F is between 2°C (275K) and 90°C (363K).
[0059] Similarly, preferably, the fourth temperature T4 of the heat transfer fluid F is between 127°C (400K) and 227°C (500K).
[0060] In one embodiment, with reference to [Fig. 3], the control system 1 comprises a second engine exchanger 42 mounted in the engine enclosure EN-M on the engine branch 21. The second engine exchanger 42 is configured to heat the fluid to be heated Q, here the fuel flow, from the heat transfer fluid F to a secondary temperature Ts, higher than the primary temperature Tp.
[0061] In this second embodiment, the primary temperature Tp of the fuel flow leaving the first tank exchanger 51 is between -173°C (100K) and -73°C (200K), so as to ensure that the fuel flow is in a gaseous state leaving the first tank exchanger 51. In this example, the secondary temperature Ts of the fuel flow leaving the second engine exchanger 42 is between -73°C (200K) and 27°C (300K), corresponding to a fuel injection temperature in the combustion chamber of the turbomachine M.
[0062] In a first embodiment (shown in [Fig.3]), the regenerative heat exchanger Exr is configured to be mounted on the circulation loop 2 upstream of the second engine exchanger 42. In a second embodiment (not shown), the regenerative heat exchanger Exr is configured to be mounted on the circulation loop 2 downstream of the second engine exchanger 42.
[0063] Still with reference to [Fig. 3], in an exemplary embodiment, the control system 1 comprises a second tank exchanger 52 mounted in the tank enclosure EN-R on the tank branch 22. The second tank exchanger 52 is configured to heat the heat transfer fluid F from calories transferred by one or more hot fluid(s) Cr available in the tank enclosure EN-R. The second tank exchanger 52 is configured to heat the heat transfer fluid F from the fifth temperature T5 to the first temperature TL. Such a second tank exchanger 52 makes it possible to use heat available on board the aircraft and thus to limit the size and bulk of an exchanger in the turbomachine.The second tank exchanger 52 also makes it possible to locally lower the temperature of the heat transfer fluid F in the first tank exchanger 51 below the minimum operating temperature Tmin and then to reheat it. This makes it possible to further lower the heat transfer fluid flow rate. In this embodiment, the fifth temperature T5 of the heat transfer fluid F at the outlet of the first tank exchanger 51 is between -123°C (150K) and 2°C (275K).
[0064] In a first embodiment (shown in [Fig.3]), the regenerative heat exchanger EXr is configured to be mounted on the circulation loop 2 upstream of the second engine exchanger 42. In a second embodiment (not shown), the regenerative heat exchanger EXr is configured to be mounted on the circulation loop 2 downstream of the second engine exchanger 42.
[0065] This document presents an example in which the control system 1 comprises one or two engine exchangers 41, 42 and one or two tank exchangers 51, 52, it goes without saying that the control system 1 could comprise a different number of engine exchangers 41, 42 and / or tank exchangers 51, 52, in particular a number greater than two tank exchangers and / or a number greater than or equal to two engine exchangers.
[0066] In one embodiment, with reference to [Fig. 4], the control system 1 comprises a controllable valve 6 mounted on the circulation loop 2 between the engine enclosure EN-M and the first reservoir exchanger 51. The controllable valve 6 makes it possible to direct a first portion of the heat transfer fluid F1 towards the first reservoir exchanger 51 and towards the engine enclosure EN-M and a second portion of the heat transfer fluid F2 towards the first engine exchanger 41. A lower flow rate of heat transfer fluid F is thus routed towards the reservoir enclosure EN-R, which makes it possible to regulate the circulation loop 2 while maintaining optimal extraction of calories in the engine sources.
[0067] In this example, the controllable valve 6 is mounted in the engine enclosure EN-M, as shown in [Fig.4]. It goes without saying that the controllable valve 6 could just as easily be mounted in the tank enclosure EN-R.
[0068] A method for controlling the temperature of the heat transfer fluid F will now be described, with reference to [Fig. 2]. The heat transfer fluid F is at the engine inlet point Pim of the engine enclosure EN-M at a first temperature Tl, in this example, lower than the minimum operating temperature Tmin. In this example, the first temperature Tl is lower than 2°C (275K).
[0069] The method comprises a first step E1 of preheating the heat transfer fluid F, at the inlet of the engine branch 21, upstream of the first engine exchanger 41, in the regenerative heat exchanger EXr, up to the second temperature T2 higher than the first temperature TL. The heat transfer fluid F is heated in the regenerative exchanger EXr by the heat transfer fluid F which circulates downstream of the first engine exchanger 41 and which has been heated by the latter. The second temperature T2 is higher than the minimum operating temperature Tmin. In this example, the heat transfer fluid F is heated, in step E1, up to a temperature between 2°C (275K) and 90°C (363K).
[0070] The heat transfer fluid F then passes through the first engine exchanger 41, in which it is heated in a step E2 to the third temperature T3, higher than the second temperature T2 and higher than the maximum operating temperature Tmax. In this example, the heat transfer fluid F is heated, in step E2, to a temperature between 227°C (500K) and 377°C (650K).
[0071] In a third step E3, the heat transfer fluid F then circulates again in the regenerative exchanger EXr where it transfers calories to the heat transfer fluid F which circulates upstream of the first engine exchanger 4L. The heat transfer fluid F is thus cooled in the regenerative exchanger EXr to a fourth temperature T4. In this example, the heat transfer fluid F is cooled, in step E3, to a temperature between 127°C (400K) and 227°C (500K).
[0072] The heat transfer fluid F is then conveyed, in a step E4, to the tank enclosure EN-R. In a fifth step E5, the heat transfer fluid F passes through the first tank exchanger 51 in the tank enclosure EN-R in which it transfers its calories to the fuel flow. The heat transfer fluid F is thus cooled to the fifth temperature T5, in this example equal to the first temperature TL
[0073] The heat transfer fluid F then circulates in the circulation loop 2 in the reservoir enclosure EN-R, that is to say in the reservoir branch 22, to be conveyed to the engine enclosure EN-M where it will be reheated in the regenerative exchanger EXr.
Claims
Claims
1. Fuel conditioning system (SC) configured to supply an aircraft turbomachine (M) with fuel (Qc) from a cryogenic tank (R) in which it is stored at an initial temperature (Ti), the conditioning system (SC) extending in a tank enclosure (EN-R) and in an engine enclosure (EN-M) separate from the tank enclosure (EN-R), the cryogenic tank (R) being mounted in the tank enclosure (EN-M) and the turbomachine (M) being mounted in the engine enclosure (EN-M), the conditioning system (SC) comprising: a fuel circuit (CQ) connected at the inlet to the cryogenic tank (R) and at the outlet to the turbomachine (M), a fuel flow (Qc) circulating from upstream to downstream in the fuel circuit (CQ), at least one mechanical pump (P) configured to circulate the fuel flow (Qc) from the cryogenic tank (R) from upstream to downstream in the fuel circuit (CQ), and a control system (1) for the temperature of a heat transfer fluid (F) configured to transfer calories to the fuel flow (Qc), the control system (1) comprising: a circulation loop (2) of the heat transfer fluid (F) extending both in the tank enclosure (EN-R) and in the engine enclosure (EN-M), the circulation loop (2) comprising: • a motor branch (21) extending in the motor enclosure (EN-M) between a motor inlet point (Pim) and a motor outlet point (P2m), the heat transfer fluid (F) circulating from upstream to downstream between the motor inlet point (Pim) and the motor outlet point (P2m), the heat transfer fluid (F) having a first temperature (Tl) at the motor inlet point (Pim), • a reservoir branch (22) extending into the reservoir enclosure (EN-R) between a reservoir inlet point (Plr) and a reservoir outlet point (P2r), the heat transfer fluid (F) circulating from upstream to downstream between the reservoir inlet point (Plr) and the reservoir outlet point (P2r), the engine output point (P2m) being fluidly connected to the tank input point (Plr), the tank output point (P2r) being fluidly connected to the engine input point (Pim), at least one mechanical pump (3) configured to circulate the heat transfer fluid (F) in the circulation loop (2), at least one first engine exchanger (41), mounted on the engine branch (21), configured to heat the heat transfer fluid (F) to a third temperature (T3) higher than the first temperature (Tl), from calories transferred by at least one hot fluid (Cm) available in the engine enclosure (EN-M), the third temperature (T3) being higher than a maximum operating temperature (Tmax), at least one first tank exchanger (51), mounted on the tank branch (22), configured to heat the fuel flow (Qc) from calories transferred by the heat transfer fluid (F) to a primary temperature (Tp), at least one regenerative heat exchanger (EXr), mounted on the engine branch (21), the regenerative heat exchanger (EXr) being configured to heat the heat transfer fluid (F) to a second temperature (T2) higher than the first temperature (Tl) and lower than the third temperature (T3), the second temperature (T2) being higher than a minimum operating temperature (Tmin), the regenerative heat exchanger (EXr) being configured to transfer calories from the heat transfer fluid (F) circulating downstream of the first engine exchanger (41) at the third temperature (T3) to the heat transfer fluid (F) circulating upstream of the first engine exchanger (41) at the first temperature (Tl),so as to allow the heat transfer fluid (F) to be heated in the first engine exchanger (41) to a temperature above the maximum operating temperature (Tmax) and to be cooled before leaving the engine enclosure (EN-M) to a temperature below the maximum operating temperature (Tmax).,
2. Conditioning system (SC) according to claim 1, wherein the first temperature (Tl) of the heat transfer fluid (F) is between -123°C (150K) and -23°C (250K).
3. Conditioning system (SC) according to one of claims 1 and 2, in which the second temperature (T2) of the heat transfer fluid (F) is between 2°C (275K) and 90°C (363K).
4. Conditioning system (SC) according to one of claims 1 to 3, in which the third temperature (T3) of the heat transfer fluid (F) is between 227°C (500K) and 377°C (650K).
5. Conditioning system (SC) according to one of claims 1 to 4, in which the fourth temperature (T4) of the heat transfer fluid (F) is between 127°C (400K) and 227°C (500K).
6. Conditioning system (SC) according to one of claims 1 to 5, in which the control system (1) comprises at least one second reservoir exchanger (52), mounted on the reservoir branch (22), the second reservoir exchanger (52) being configured to heat the heat transfer fluid (F) from calories transferred by at least one hot fluid (Cr) available in the reservoir enclosure (EN-R), the second reservoir exchanger (52) being configured to heat the heat transfer fluid (F) from a fifth temperature (T5) reached at the outlet of the first reservoir exchanger (51) to the first temperature (T1).
7. Conditioning system (SC) according to one of claims 1 to 6, in which the control system (1) comprises at least one second engine exchanger (42) mounted on the engine branch (21) upstream of the first engine exchanger (41), the second engine exchanger (42) being configured to heat the fuel flow (Qc) from the heat transfer fluid (F) to a secondary temperature (Ts) higher than the primary temperature (Tp).
8. Conditioning system (SC) according to one of claims 1 to 7, in which the primary temperature (Tp) of the fuel flow (Qc) at the outlet of the first tank exchanger (51) is between -173°C (100K) and -73°C (200K).
9. Conditioning system (SC) according to one of claims 1 to 7, in which the primary temperature (Tp) of the fuel flow (Qc) at the outlet of the first tank exchanger (51) is between -73°C (200K) and 27°C (300K).
10. Aircraft comprising a cryogenic tank (R), a turbomachine (M) and conditioning system (1) according to one of claims 1 to 9 for supplying the turbomachine (M).
11. Method for controlling the temperature of a heat transfer fluid (F) by means of the control system (1) of a conditioning system (SC) according to one of claims 1 to 9, the heat transfer fluid (F) being initially at the engine inlet point (Pim) at a first temperature (Tl), the method comprising the steps of: • preheating the heat transfer fluid (F) upstream of the first engine exchanger (41), in the regenerative heat exchanger (EXr), to a second temperature (T2) higher than the first temperature (Tl) and the minimum operating temperature (Tmin), • heating the heat transfer fluid (F) in the first engine exchanger (41) to a third temperature (T3) higher than the second temperature (T2) and higher than the maximum operating temperature (Tmax), • cooling the heat transfer fluid (F) downstream of the first engine exchanger (41), in the heat exchanger regenerator (EXr),up to a fourth temperature (T4) lower than the third temperature (T3) and lower than the maximum operating temperature (Tmax).,
12. Control method according to claim 11 wherein the first temperature (Tl) is lower than the minimum operating temperature (Tmin).