Fuel conditioning system for supplying fuel to an aircraft turbomachine
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- SAFRAN SA
- Filing Date
- 2022-03-11
- Publication Date
- 2026-07-31
AI Technical Summary
Existing fuel conditioning systems for aircraft turbomachines require multiple heat exchangers, leading to a significant bulk that is undesirable for integration into aircraft, and there is a risk of damage due to hot fluids freezing in the heating modules.
A single recirculating heat exchanger with three conduits is used to heat fuel from a cryogenic tank, where the first conduit heats the fuel to a primary temperature above its vaporization point, the second conduit heats it to a secondary temperature suitable for injection, and the third conduit carries a hot fluid to transfer calories without mixing, all within a compact design.
The system efficiently heats the fuel to prevent icing while reducing bulk and risk of damage, ensuring reliable operation and easier integration into aircraft.
Smart Images
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Abstract
Description
Description Title of the invention: Fuel conditioning system for supplying fuel to an aircraft turbomachine technical field
[0001] — The present invention relates to the field of aircraft comprising one or more turbomachinery powered by fuel stored in a cryogenic tank.
[0002] It is known to store fuel, in particular hydrogen, in the form liquid to reduce the size and weight of the aircraft's tanks. As such For example, the fuel is stored at a temperature of around 20 to 22 Kelvin (- 253 to -251°C) in a cryogenic tank of the aircraft.
[0003] — In order to be able to be injected into the combustion chamber of a turbomachine, the Fuel must be conditioned, that is, pressurized and heated, in order to allow a Optimal combustion. Conditioning is necessary, for example, to reduce the risk of icing, that is, the solidification of water vapor contained in the air which circulates in the turbomachine, in particular, at the level of the fuel injectors of the turbomachine. With reference to [Fig. 1], a conditioning system is shown. SCAA operation according to the prior art including a fuel circuit 101 connected in input to a cryogenic tank R and output to the combustion chamber CC of a turbomachine M. A fuel flow Q circulating from upstream to downstream in the circuit of fuel 101 passes successively through a mechanical pump 102 and a module of Heating 103. Pump 102 allows the upstream fuel flow to circulate downstream.
[0004] — In a known manner, a heating module 103 allows the circulation of one or Several hot fluids to provide heat to the fuel flow Q. Each The hot fluid can be either a heat transfer fluid or a fluid from a source hot air available on board the aircraft (such as hot air, gases) hot at the turbomachine outlet, hot engine oil, etc.). Due to the temperature very low temperature of the fuel flow Q at the outlet of the cryogenic tank R, it There is a risk that the hot fluid circulating in the heating module 103 may freeze. in heating module 103, which can damage heating module 103 or affect its performance.
[0005] — With reference to [Fig.2], a SCAA conditioning system is known fuel comprising two separate heat exchangers 131, 132 successively mounted itively in the fuel circuit 101. The first exchanger 131, of type fuel / fuel heat exchanger, allows heating of the fuel flow Q up to a primary temperature T1, higher than the solidification temperature of A hot fluid (i.e., here at the fuel's freezing temperature) is circulated so that the fuel is in a gaseous state. The second heat exchanger 132, through which a hot fluid circulates, heats the fuel stream to a secondary temperature T2, higher than the primary temperature T1. At the outlet of the second heat exchanger 132, the fuel stream Q recirculates into the first heat exchanger 131 to reheat the fuel stream Q from the cryogenic tank R to the primary temperature T1. The fuel stream Q, having reached a sufficiently high temperature at the outlet of the second heat exchanger 132, can then be introduced into the turbomachine M. However, such a conditioning system requires two successive heat exchangers: a first exchanger to prevent any risk of the hot fluid freezing, and a second exchanger to heat the fuel sufficiently for it to be introduced into the turbomachine.The prior art packaging system thus has a significant bulk, which is undesirable for installation in an aircraft. The invention thus aims to eliminate at least some of these disadvantages by proposing a new fuel conditioning system allowing efficient and reliable heating while limiting the size of the conditioning system to facilitate its integration into an aircraft. PRESENTATION OF THE INVENTION The invention relates to a fuel conditioning system configured to supply an aircraft turbomachine with fuel from a cryogenic tank, the conditioning system comprising: a fuel circuit connected at the inlet to the cryogenic tank and at the outlet to the turbomachine, a fuel flow circulating from upstream to downstream in the circuit fuel at least one recirculating heat exchanger, mounted in the circuit of fuel and configured to transfer calories to the fuel flow, The recirculating heat exchanger is remarkable in that it includes an enclosure comprising: at least one initial fuel flow circulation conduit, mounted in the enclosure, the first conduit being configured for heat the fuel flow to a temperature at least equal to one predetermined primary temperature, at least one second fuel flow recirculation duct, mounted in the enclosure, the second conduit being configured for heat the fuel flow to a temperature at least equal to one predetermined secondary temperature, the secondary temperature being greater than the primary temperature, and at least a third hot fluid circulation conduit mounted within the enclosure, the second circulation duct being mounted between the first conduit and the third conduit. Thanks to the conditioning system according to the invention, the third conduit transfers calories from a hot fluid to the fuel flow circulating in the second conduit, which itself transfers calories to the fuel flow circulating in the first conduit. The conditioning system according to the invention allows, within a single enclosure, the heating of the fuel stream from a cryogenic tank using a hot fluid, without the risk of the fluid freezing. Thanks to the invention, the heat exchanger has a longer service life because it is less susceptible to damage. Furthermore, the efficiency of the heat exchanger is not affected, ensuring that the fuel injected into the turbomachine from the heat exchanger outlet is at a sufficiently high temperature to prevent any risk of injector icing in the turbomachine. Preferably, the hot fluid is a heat transfer fluid or a fluid from a heat source available on board the aircraft, such as hot gases exiting a low-pressure turbine of the turbomachine, hot oils, hot air, etc. Preferably, the fuel conditioning system comprises a single recirculating heat exchanger. This significantly reduces the system's footprint compared to prior art designs. It is also advantageously easier to integrate into an aircraft's turbomachine. Furthermore, the conditioning system has a reduced mass, which is beneficial given the weight constraints inherent in the aeronautical field. In a preferred embodiment, the first and second ducts of the recirculating heat exchanger are fluidically connected, allowing the fuel flow to circulate between the first circulation duct and the second recirculation duct. In other words, the fuel flow circulating in the first duct can flow directly into the second duct. Preferably, the third circulation line is not fluidly connected to either the first or second circulation line, so as to eliminate any risk of the hot fluid mixing with the fuel flow. Preferably, the fuel flow in the first conduit follows a first direction of flow, and the fuel flow in the second conduit follows a second direction of flow, opposite to the first direction of flow. In one embodiment, the first conduit and the second conduit being coaxial, the first conduit is mounted inside the second conduit, so as to form A second peripheral conduit surrounds the first conduit. This second peripheral conduit efficiently heats the fuel flow within the first conduit. This embodiment advantageously ensures that the entire fuel flow within the first conduit is heated uniformly, guaranteeing that the fuel exiting the first conduit is entirely in a gaseous state. A fuel flow entirely in a gaseous state thus eliminates the risk of freezing the hot fluid upon entering the second conduit. In an alternative embodiment, the first, second, and third conduits are parallelepiped-shaped plates, with the second conduit adjacent to both the first and third conduits. This embodiment provides a large heat exchange surface area between the conduits, enabling the hot fluid to rapidly heat the fuel flow in the second conduit and the second conduit to rapidly heat the fuel flow in the first conduit. In one embodiment, the recirculating heat exchanger comprises: a plurality of primary conduits configured to heat the flow of fuel up to a temperature at least equal to the primary temperature, a plurality of secondary conduits configured to heat the flow of fuel up to a temperature at least equal to the secondary temperature, And at least a third conduit, each second conduit being mounted respec- tively between one of the plurality of first conduits and the third conduit. This embodiment allows for efficient and rapid heating of the fuel stream by introducing the fuel from the cryogenic tank into a plurality of first conduits, each with a limited volume. This simplifies the process of heating the fuel stream to a gaseous state, as a larger surface area of the first conduits is in contact with the second conduits through which the hot fuel flows. In an alternative embodiment, the recirculating heat exchanger comprises: a plurality of first conduits configured to heat the (flux of fuel up to a temperature at least equal to the primary temperature, a plurality of secondary conduits configured to heat the flow of fuel up to a temperature at least equal to the secondary temperature, each first conduit being mounted inside one of the second ones conduits, and a single third conduit, the plurality of first conduits, and the plurality of second conduits being mounted inside the third conduit, so as to make circulate the hot fluid through a single conduit while being in contact with all the second set of conduits. In this embodiment, the fuel flow circulating in the first conduits is efficiently heated due to the limited volume of each first conduit. The cold, liquid fuel in each first conduit is heated by peripheral contact with one of the second conduits carrying a warmer fuel flow. Since the periphery of the first conduit heats up before its center, a conduit with a smaller volume more easily heats the entire volume. A single third conduit provides a simple heat exchanger in which the hot fluid flows directly, thus heating all the second conduits. In one embodiment, the heat exchanger is a plate exchanger, comprising an alternation of first fuel flow circulation plates, second fuel flow recirculation plates, and third hot fluid circulation plates, each second fuel flow recirculation plate being adjacent to a first fuel flow circulation plate and a third hot fluid plate.Such a plate-like embodiment advantageously maximizes the exchange surface area between each first fuel flow circulation plate and each second fuel flow recirculation plate, and between each second fuel flow recirculation plate and each third hot fluid circulation plate, allowing efficient heating of both the fuel flow in the first conduits (here the first plates) and in the second conduits (here the second plates). Preferably, since the fuel stream has a vaporization temperature, the primary temperature is higher than the vaporization temperature. Besides eliminating the risk of solidification, the first conduit allows the liquid phase of the fuel stream to be removed, leaving only the gaseous phase, which can then be easily and conveniently heated by the second conduit. In cases where the fuel pressure is below its critical pressure (subcritical case), the primary heat exchanger allows the fuel phase change to occur, leaving only the gaseous phase, which can then be easily heated in the secondary heat exchanger. In a preferred embodiment, the hot fluid having a predetermined solidification temperature, the primary temperature is greater than the predetermined solidification temperature of the hot fluid. According to a preferred aspect, the primary temperature is between 100K and 220K. Preferably, the secondary temperature is between 250K and 350K. The invention also relates to a method of supplying fuel to an aircraft turbomachine from fuel from a cryogenic tank by means of a conditioning system as described above, a fuel flow circulating from upstream to downstream in the fuel circuit connecting the cryogenic tank at the inlet and the turbomachine at the outlet, the method comprising steps consisting of: heat the fuel flow, in the first conduit, to at least the primary temperature, heat the fuel flow, in the second conduit, until at least the secondary temperature higher than primary temperature, the first conduit extracting calories from the fuel flow having at least the temp- secondary operating temperature. PRESENTATION OF THE FIGURES The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects. The [Fig.1] is a schematic representation of an early conditioning system according to the prior art. Fig. 2 is a schematic representation of a second conditioning system according to the prior art. Figure 3 is a schematic representation of a conditioning system according to one embodiment of the invention. Fig. 4 is a schematic representation of a heat exchanger of the conditioning system of Fig. 3 according to a first embodiment of the invention. Fig. 5 is a schematic representation of a heat exchanger of the conditioning system of Fig. 3 according to a second embodiment of the invention. Fig. 6 is a schematic representation of a heat exchanger of the conditioning system of Fig. 3 according to a third embodiment of the invention. The [Fig.7] is a schematic representation of an example of fuel and hot fluid flow circulation in the heat exchanger of [Fig.6]. It should be noted that the figures illustrate the invention in detail for implementing the invention; these figures can, of course, be used to better define the invention, if applicable. DETAILED DESCRIPTION OF THE INVENTION With reference to [Fig.3], a fuel conditioning system SC is shown configured to supply an aircraft turbomachine M with fuel Q from a cryogenic tank R. The turbomachine M is configured to provide propulsion for the aircraft, in particular, by driving at least one propulsion unit (not shown in [Fig.3]). In this example, the fuel Q in the cryogenic tank R is hydrogen and is stored at an initial temperature TO of approximately 20 to 22 Kelvin (-253 to -251°C). At this temperature, the fuel Q is liquid. A conditioning system SC is described in which the fuel Q is liquid hydrogen, but the invention is applicable to other types of fuel, for example, liquid methane or liquefied natural gas. According to one embodiment of the invention, with reference to [Fig.3], the conditioning system SC comprises a fuel circuit 1 (solid line on [Fig.3]) connected inlet to the cryogenic tank R and outlet to the turbomachine M. The conditioning system SC also includes a pump 2, preferably high pressure, configured to circulate a fuel flow Q from upstream to downstream in the fuel circuit 1. With further reference to [Fig.3], the SC conditioning system includes a recirculating heat exchanger 3, mounted in the fuel circuit 1 and configured to transfer calories to the fuel flow Q in order to warm it up to allow its optimal injection into the turbomachine M. The SC conditioning system preferably includes a single recirculating heat exchanger 3, which advantageously allows for a significant space saving. The recirculating heat exchanger 3 according to the invention allows, within the same piece of equipment, the heating of a cold fuel stream Q, hereinafter referred to as the "direct fuel stream" Qd, from the cryogenic tank R, with a hot fuel stream Q that has itself been heated by a hot fluid F, hereinafter referred to as the "recirculated fuel stream" Qr, as will be described in more detail later. In this example, the hot fluid F is a heat transfer fluid. It goes without saying that the hot fluid F could just as easily be a fluid from a heat source on board the aircraft, such as hot gases exiting a low-pressure turbine of the turbomachine, hot oils, hot air, etc. The recirculating heat exchanger 3 can be placed either within the aircraft perimeter (near the cryogenic tank R, short piping between pump 2 and recirculating heat exchanger 3), or within the perimeter of the turbomachine M (piping long between pump 2 and heat exchanger 3). According to the invention, with reference to [Fig. 3], the recirculating heat exchanger 3 comprises a housing 30 including a first circulation duct 31 for the fuel flow Q, a second recirculation duct 32 for the fuel flow Q, and a third circulation duct 33 for the hot fluid F. The term "duct" means a circulation volume including an inlet and an outlet for the fuel flow Q or the hot fluid F. As such, each duct 31, 32, 33 can be either a cylindrical tube (as shown in [Fig. 4]), a parallelepiped plate (as shown in [Fig. 6]) or even a cubic volume (as shown in [Fig. 5]), as will be described in more detail later. In this example, with reference to [Fig. 4], the recirculating heat exchanger 3 has a cylindrical shape. The three ducts 31, 32, 33 also have a cylindrical shape. In one embodiment, the first conduit 31 and the second conduit 32 are coaxial, with the first conduit 31 mounted inside the second conduit 32. In this example, the third conduit 33 is also coaxial with the first conduit 31 and the second conduit 32. The first conduit 31 and the second conduit 32 are mounted inside the third conduit 33, as shown in [Fig. 4]. In other words, in this example, the first conduit 31 extends inside the second conduit 32, which itself extends inside the third conduit 33. To form the three conduits 31, 32, 33, still with reference to [Fig.4], the recirculating heat exchanger 3 comprises an inner wall 34, an intermediate wall 35 and an outer wall 36. The inner wall 34 and the intermediate wall 35 are configured to allow heat exchange between the different conduits 31, 32, 33, as will be described in more detail later. In this example, the enclosure 30 has the shape of a solid cylinder. In the enclosure 30, the first conduit 31 is radially delimited externally by the inner wall 34. The second conduit 32 is radially delimited internally by the inner wall 34 and externally by the intermediate wall 35. The third conduit 33 is radially delimited internally by the intermediate wall 35 and externally by the outer wall 36. In one embodiment, the inner wall 34 and the intermediate wall 35 include secondary exchange surfaces (not shown), for example fins, so as to increase the heat exchanges respectively between the first duct 31 and the second duct 32 and between the second duct 32 and the third duct 33. Such secondary exchange surfaces make it possible to improve the aerothermal performance of the recirculating heat exchanger 3. A recirculating heat exchanger 3 is described, having a cy- shape Lindrique, however it goes without saying that the recirculating heat exchanger 3 can have a different shape, in particular a parallelepiped shape, as shown in figures 5 to 7. Similarly, a recirculating heat exchanger 3 is described comprising a single first conduit 31, a single second conduit 32, and a single third conduit 33; however, it is understood that the recirculating heat exchanger 3 could just as easily comprise a different number of conduits 31, 32, 33, in particular a number greater than or equal to two first conduits 31, a number greater than or equal to two second conduits 32, and / or a number greater than or equal to two third conduits 33 (as shown in [Fig. 7]). Likewise, it is understood that the recirculating heat exchanger 3 could just as easily comprise at least two first conduits 31, at least two second conduits 32, and a single third conduit 33 (as shown in [Fig. 5]). With reference to Figures 3 and 4, the first fuel flow circulation conduit 31 Q is configured to heat the direct fuel flow Qd from the cryogenic tank R to a temperature at least equal to a predetermined primary temperature T1. The first conduit 31 is in contact with the second conduit 32, via the inner wall 34, so as to allow the direct fuel flow Qq to be heated to the primary temperature T1, as will be described in more detail later. The first conduit 31 is fluidically connected to the second conduit 32, so as to allow the passage of the fuel flow Q from the first conduit 31 to the second conduit 32. In other words, the first conduit 31 is fluidly connected upstream to the cryogenic tank R and downstream to the second conduit 32. According to the invention, the primary temperature T1 is higher than the vaporization temperature of the fuel Q. Thus, at the outlet of the first conduit 31, the direct fuel flow Qd is in a gaseous state, which facilitates its heating by the second conduit 32. Preferably, the primary temperature T1 is between 100 and 220 K (between -173 and -53 °C). In this example, the primary temperature T1 is greater than 65 K (-208 °C) so that it is higher than the solidification temperature of the hot fluid F (in this example, nitrogen). The first conduit 31 thus allows preliminary heating without risk of solidification of the hot fluid F, the liquid phase of the fuel flow Q being eliminated in a practical way. The second fuel flow recirculation conduit 32 is configured to heat the recirculated fuel flow Qr, coming from the first conduit 31, to a temperature at least equal to a predetermined secondary temperature T2. The secondary temperature T2 is higher than the primary temperature T1. Preferably, the Secondary temperature T2 is between 250 and 350 K. As described previously, the second conduit 32 is in contact with the first conduit 31, via the inner wall 34, so as to allow the direct fuel flow Qd to be heated to the primary temperature T1 in the first conduit 31 by the recirculated fuel flow Qr. The second conduit 32 is also in contact with the third conduit 33, via the intermediate wall 35, so as to allow the recirculated fuel flow Qr to be heated to the secondary temperature T2 by means of the hot fluid F, as will be described in more detail later. As described previously, the second conduit 32 is fluidly connected at its inlet to the first conduit 31 so as to allow the introduction into the second conduit 32 of the direct fuel flow Qd, preheated to the primary temperature T1. The second conduit 32 is fluidly connected at its outlet to the turbomachine M, so as to inject the recirculated fuel flow Qr, heated to the secondary temperature T2, into the combustion chamber of the turbomachine M. In other words, the second conduit 32 is fluidly connected upstream to the first conduit 31 and downstream to the turbomachine M. Indeed, the injection temperature of the fuel flow Q into the turbomachine M should preferably be around 250K to 300K, in particular to limit the 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. Consequently, the secondary temperature T2 of the fuel flow Q at the outlet of the recirculating heat exchanger 3, more precisely at the outlet of the second conduit 32, must be higher than this injection range since the hot fluid F is cooled during its passage through the heat exchanger 3, in contact with the first conduit 31. As shown in Figures 3 and 4, the direct fuel flow Qd circulates in the first conduit 31 in a first direction of flow, and the recirculated fuel flow Qr circulates in the second conduit 32 in a second direction of flow. Preferably, the second direction of flow is opposite to the first direction of flow. In this example, the third conduit 33 allows the circulation of a hot fluid F. As described previously, the third conduit 33 is in contact with the second conduit 32, via the intermediate wall 35, so as to allow the heating of the recirculated fuel flow Qr in the second conduit 32 to the secondary temperature T2. The third conduit 33 is not fluidically connected to either the first conduit 31 or the second conduit 32, so as to avoid any mixing between the hot fluid F and the fuel flow Q. Preferably, the hot fluid F is nitrogen, having a solidification temperature of fication of the order of 63 K (-210°C), or of carbon dioxide, having a solidification temperature of the order of 217 K (-56°C). A method for supplying fuel to a turbomachine M will now be described, according to an embodiment of the invention, with reference to figures 3 and 4. In this example, the pump 2 circulates the fuel flow Q from the cryogenic tank R in the fuel circuit 1 to the turbomachine M. The process is described in this example for a recirculating heat exchanger 3 comprising a single first conduit 31 for circulating the direct fuel flow Qr, a single second conduit 32 for recirculating the recirculated fuel flow Qr and a single third conduit 33 for circulating the hot fluid F. In this implementation example, the fuel Q is dihydrogen and the hot fluid F circulating in the recirculating heat exchanger 3 is a heat transfer fluid, in this case nitrogen. This document presents an example in which the hot fluid F is a heat transfer fluid; however, it is understood that the hot fluid could just as easily be any fluid from a heat source available on board the aircraft. Fuel Q is initially stored in cryogenic tank R at a temperature of approximately 20 to 22 K (-253 to -251 °C) and is in a liquid state. In the feeding process, with reference to [Fig.3], the direct fuel flow Qd, from the cryogenic tank R, enters the enclosure 30 of the recirculating heat exchanger 3, where it is introduced into the first conduit 31. The recirculated fuel flow Qr then flows into the second conduit 32, then exits the enclosure 30 of the recirculating heat exchanger 3 to go to the turbomachine M. The process includes a first step El of heating the direct fuel flow Qd in the first conduit 31 to the primary temperature T1, in this example equal to 100K. The direct fuel flow Qd then changes to a gaseous state and enters the second conduit 32. This state and temperature limit the risk of solidification of the hot fluid F in the third conduit 33, which is in contact with the second conduit 32. At the outlet of the first conduit 31, the direct fuel flow Qd is designated as the "recirculated fuel flow Qr". In a second stage E2, the recirculated fuel flow Qr circulating in the second conduit 32 is heated to the secondary temperature T2, in this example 300 K. During this stage, the hot fluid F circulates in the third conduit 33. More precisely, the hot fluid F, initially at a temperature of, for example, 550 K, transfers heat to the recirculated fuel flow Qr, via the intermediate wall 35. By transferring heat, the temperature of the hot fluid F drops to a temperature between 250 and 550 K. The recirculated fuel flow Qr present in the second conduit 32 and heated to the secondary temperature T2 transfers calories to the direct fuel flow Qd present in the first conduit 31, via the inner wall 34, allowing the direct fuel flow Qd in the first conduit 31 to be heated to the primary temperature T1, so that it passes into the gaseous state. After supplying calories to the first conduit 31 via the inner wall 34, the recirculated fuel flow Qr exits the second conduit 32 and is injected into the turbomachine M at a temperature, in this example, of the order of 300K preventing any icing of the injectors. In a second embodiment, shown in [Fig.5], the recirculating heat exchanger 3 is of the "tube exchanger" type. With reference to [Fig. 5], in this embodiment, the recirculating heat exchanger 3 comprises a plurality of first conduits 31, a plurality of second conduits 32 and a single third conduit 33. Each first conduit 31 is mounted respectively in one of the plurality of second conduits 32. For clarity, [Fig. 5] presents an exploded view of the recirculating heat exchanger 3. In this example, the direct fuel flow Qd, in the liquid state, enters each first conduit 31 where it is heated to the primary temperature T1 and changes to the gaseous state. Each of the first conduits 31 is fluidically connected respectively to one of the second conduits 32. The recirculated fuel flow Qr then passes respectively into each of the second conduits 32, where it is heated to the secondary temperature T2, thanks to the hot fluid F which circulates in the third conduit 33, all around the plurality of second conduits 32.The recirculated fuel flow Qr present in each second conduit 32 heats the direct fuel flow Qd present in each first conduit 31 and exits the recirculating heat exchanger 3 to join the turbomachine M at a temperature high enough to avoid any risk of icing in the turbomachine M. In this embodiment, the second conduits 32 are in the form of blind pipes which are immersed in the third conduit 33 in which the hot fluid F circulates. In a third embodiment, shown in Figures 6 and 7, the recirculating heat exchanger 3 is of the "plate heat exchanger" type. In this example, the recirculating heat exchanger 3 comprises several first conduits 31, several second conduits 32, and several third conduits 33. With reference to Figures 6 and 7, in this embodiment, the recirculating heat exchanger 3 comprises a plurality of plates including alternating first and second plates. The first plates have alternating first conduits 31 and third conduits 33, and the second plates plates include one or more second conduits 32. In other words, each second conduit 32 in the form of a plate, is adjacent to both a first conduit 31 and a third conduit 33, so as, on the one hand, to take calories from the hot fluid F present in each third conduit 33 to transfer them to the recirculated fuel flow Qr present in each second conduit 32 and, on the other hand, to transfer calories to the direct fuel flow Qd present in each first conduit 31, so as to heat it up to the primary temperature T1. Thanks to the invention, the fuel is conveniently heated using a single heat exchanger without the risk of solidification, allowing the turbomachine to be powered under optimal conditions.
Claims
Demands
1. DC fuel conditioning (SC) system configured to supply an aircraft turbomachine (M) powered by fuel (Q) from a cryogenic reservoir (R), conditioning system (SC) including: a fuel circuit (1) connected at the inlet to the tank cryogenic (R) and at the outlet to the turbomachine (M), a flow of fuel (Q) flowing from upstream to downstream in the circuit of fuel (1), at least one recirculating heat exchanger (3), mounted in the fuel circuit (1) and configured to transmit calories to fuel flow (Q), the recirculating heat exchanger (3) being characterized in which includes an enclosure (30) comprising: at least one first conduit (31) for circulation of the fuel flow (Q), mounted in the enclosure (30), the first conduit (31) being configured to heat the fuel flow (Q) at a temperature at least equal to a predetermined primary temperature (T1), at least one second recirculation duct (32) of the fuel flow (Q), mounted in the enclosure (30), the second conduit (32) being configured for heat the fuel flow (Q) to a temperature at less than or equal to a predetermined secondary temperature (T2) when finished, the secondary temperature (T2) being su- above the primary temperature (T1), and at least a third circulation conduit (33) of a hot fluid (F), mounted in the enclosure (30), the second circulation conduit (32) being mounted between the first conduit (31) and the third conduit (33).
2. Fuel conditioning system (SC) according to claim 1 including a single recirculating heat exchanger (3).
3. Fuel conditioning (SC) system according to any one of the claims indications 1 to 2, in which the first leads (31) and the second The conduit (32) of the recirculating heat exchanger (3) are connected fluidly.
4. Fuel conditioning (SC) system according to one of the claims indications 1 to 3, in which the fuel flow (Q) circulating in the first conduit (31) according to a first direction of traffic, the flow of fuel (Q) flowing in the second conduit (32) flows according to a second direction of traffic, opposite to the first direction of traffic.
5. Fuel conditioning (SC) system according to one of the claims indications 1 to 4, in which the first leads (31) and the second conduit (32) being coaxial, the first conduit (31) is mounted in the second conduit (32), so as to form a second conduit (32) peripheral around the first conduit (31).
6. Fuel conditioning (SC) system according to one of the claims indications 1 to 4, in which the first leads (31), the second leads (32) and the third conduit (33) are in the form of plates parallelepipeds, the second conduit (32) being adjacent to the first conduit (31) and to the third conduit (33).
7. Fuel conditioning (SC) system according to one of the claims indications 1 to 6, in which the recirculating heat exchanger (3) understand : a plurality of first conduits (31) configured for heat the fuel flow (Q) to a temperature at less than or equal to the primary temperature (T1), a plurality of second conduits (32) configured for heat the fuel flow (Q) to a temperature at less than or equal to the secondary temperature (T2), and at least one third conduit (33), every second conduit (32) having mounted respectively between one of the plurality of first conduits (31) and the third conduit (33).
8. Fuel conditioning (SC) system according to one of the claims indications 1 to 7, in which the fuel flow (Q) having a temp- vaporization temperature, the primary temperature (T1) is higher than the vaporization temperature.
9. Fuel conditioning (SC) system according to one of the claims indications 1 to 8, in which the hot fluid (F) has a temperature of predetermined solidification, the primary temperature (T1) is higher at the predetermined solidification temperature of the hot fluid (F).
10. Fuel conditioning system (SC) according to any one of the claims indications 1 to 9, in which the primary temperature (T1) is included between 100K and 220K.
11. Fuel conditioning (SC) system according to one of the claims indications 1 to 10, in which the secondary temperature (T2) is between 250K and 350K.
12. Method for supplying fuel to an aircraft turbomachine (M) from fuel (Q) from a cryogenic tank (R) by means of of a conditioning system (CS) according to any one of claims 1 at 11, a fuel flow (Q) circulating from upstream to downstream in the circuit fuel (1) connecting at the inlet to the cryogenic tank (R) and at exiting the turbomachine (M), the process comprising steps consisting has: heat the fuel flow (Q), in the first conduit (31), up to at least the primary temperature (T1), heat the fuel flow (Q), in the second conduit (32), up to at least the secondary temperature (T2) su- above the primary temperature (T1), the first conduit (31) extracting calories from the fuel stream (Q) having at least the secondary temperature (T2).