Cryogenic fuel supply system for an aircraft engine and method for maintaining such an system

Abstract

The present invention relates to a cryogenic fuel supply assembly (5) for an aircraft engine (1), comprising: - a cryogenic pipeline (7), in which the cryogenic fuel is liquid in a first operating mode and is vaporized in a second operating mode, - at least one heating installation (9) comprising an arm (25), from which extends a forearm (27) movable between a first position and a second position, the arm (25) being subjected to a heat input, in the first position, the forearm (27) being distant from the cryogenic pipeline (7), in the second position, the forearm (27) being in thermal conduction with the cryogenic pipeline (7) to create a thermal bridge between the cryogenic pipeline (7) and the arm (25).The invention also relates to an aircraft engine (1) equipped with such an assembly (5), an aircraft equipped with such an aircraft engine (1), and a method for maintaining such an assembly (5). Figure for the abstract: Fig. 2.

Description

Title of the invention: Cryogenic fuel supply system for an aircraft engine and method for maintaining such a system. FIELD OF THE INVENTION

[0001] The present invention relates to a cryogenic fuel supply assembly for an aircraft engine, to an aircraft engine comprising such an assembly, to an aircraft comprising at least one such aircraft engine, and to a method for maintaining such an assembly. 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 already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0003] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain aeronautical components and products that are less energy-intensive, more environmentally friendly, and whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using virtuous methods and operating virtuous development, manufacturing and maintenance processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, cryogenic aeronautical fuels.

[0006] Thus, the use of liquid hydrogen is advantageous because it makes it possible to reduce CO2 emissions to zero.

[0007] Another usable cryogenic fuel is "liquefied" natural gas (known by the acronym LNG), which, compared to liquid hydrogen, has the additional advantage of being able to be used at a much higher temperature, since its liquefaction temperature at 1 bar (105Pa) is -161 °C compared to -252 °C for liquid hydrogen, which simplifies its use.

[0008] In both of the aforementioned cases, it remains necessary to transport these cryogenic fuels in liquid form, so that their volume to be transported in the aircraft is acceptable, then to vaporize them and therefore to heat them up in order to be able to use them, for example in a combustion chamber of an aircraft engine.

[0009] Thus, it is known to produce a cryogenic fuel supply assembly for an aircraft engine. Such an assembly classically comprises a cryogenic pipeline, through which, in normal operating mode, the cryogenic fuel in liquid form passes, which is suitable for supplying an aircraft engine after being vaporized, in particular in a vaporization exchanger mounted downstream of the cryogenic pipeline.

[0010] However, particularly for the maintenance of such an assembly or for the overhaul of an aircraft engine, it is sometimes necessary to carry out an inerting process, which consists of replacing the cryogenic fuel in its liquid state with an inert gas. For example, to inertize a cryogenic hydrogen fuel supply assembly, that is to say, to make it suitable for safe handling by an operator, a maintenance procedure prior to inerting consists of replacing the liquid hydrogen in the cryogenic line with gaseous hydrogen before introducing an inert gas such as helium or nitrogen.

[0011] A first known solution for carrying out this preliminary step is to wait for the natural vaporization of the liquid hydrogen. In this case, vaporization occurs solely due to naturally occurring heat inputs, for example, heat inputs from the supports of the cryogenic piping or from the junctions of the cryogenic piping to other elements of the supply circuit. However, in this case, the vaporization time is long, on the order of several tens of minutes to several hours, and depends in particular on the number of supports.

[0012] A second known solution for carrying out this preliminary step more quickly is to flush the liquid hydrogen with gaseous hydrogen within the cryogenic line. However, such a solution has the disadvantage of consuming gaseous hydrogen without being able to recover it. Furthermore, an assembly incorporating such a solution is more complex, particularly because it requires, for example, return lines for the already vaporized gaseous hydrogen downstream. of the cryogenic pipeline, or to put into operation a specific heat exchanger to vaporize the liquid hydrogen contained in the cryogenic pipeline before its expulsion into the atmosphere.

[0013] Such an assembly thus requires heating the liquid cryogenic fuel in the cryogenic pipeline to vaporize it in a maintenance operating mode, such an operating mode being prior to the inerting process.

[0014] Therefore, there is a need to accelerate the vaporization of the liquid cryogenic fuel in the cryogenic pipeline in certain operating modes, particularly in the event of maintenance, while limiting the complexity of the cryogenic fuel supply system and limiting the impact on normal operation, and this without consuming additional cryogenic fuel or electrical energy. Description of the invention

[0015] The present invention aims to overcome all or part of the drawbacks mentioned above.

[0016] In particular, the invention aims to provide a cryogenic fuel supply system for an aircraft engine that allows the cryogenic fuel to be vaporized in liquid form in the cryogenic line in a simple and rapid manner, while limiting the complexity of the cryogenic fuel supply system and limiting the impact on normal operation, and this without consuming additional cryogenic fuel.

[0017] To this end, the invention is the result of technological research aimed at contributing to the reduction of the environmental impact of aircraft such as airplanes.

[0018] To this end, according to a first aspect, the invention proposes a cryogenic fuel supply system for an aircraft engine, remarkable in that it comprises: - a cryogenic pipeline suitable for containing cryogenic fuel, in which the cryogenic fuel is in a liquid state in a first operating mode so as to supply an aircraft engine and is suitable for being vaporized in a second operating mode, - at least one heating installation comprising a fixedly mounted arm, at a first end of which extends a movable forearm between a first position and a second position, the arm being distant from the cryogenic pipeline and being subjected, in the second operating mode, to a heat input at a second end opposite to the first end, in the first position,the forearm being distant from the cryogenic pipe so that the forearm and the cryogenic pipe are thermally insulated from each other, in the second position, the forearm is in thermal conduction with the cryogenic pipe and is able to create a thermal bridge between the cryogenic pipe and the arm so as to vaporize the cryogenic fuel contained in the cryogenic pipe.

[0019] Thus, an assembly is available that allows for the simple and rapid vaporization of cryogenic fuel in liquid form within the cryogenic pipeline, while limiting the complexity of the cryogenic fuel supply system and minimizing the impact on normal operation, all without consuming additional cryogenic fuel. Indeed, the use of a movable forearm limits heat loss in the first operating mode, which is notably a normal operating mode, while increasing heat transfer between the cryogenic pipeline and the arm in the second operating mode, which is notably a pre-maintenance operating mode prior to inerting.In other words, the proposed solution, in the second operating mode, forms a thermal bridge to provide heat to the liquid cryogenic fuel and vaporize it without the need for additional cryogenic fuel or electrical energy.

[0020] Such a thermal bridge thus corresponds to a forearm that comes into contact with the cryogenic pipeline when it is necessary to vaporize the cryogenic fuel contained within it. During nominal operating phases, this forearm is kept away from the cryogenic pipeline to avoid vaporizing the liquid cryogenic fuel when this is undesirable. Indeed, during nominal operation, the cryogenic fuel must remain liquid in the cryogenic pipeline, for example, upstream of a vaporization exchanger designed to vaporize the cryogenic fuel into a gaseous fuel to supply the aircraft engine with gaseous fuel.

[0021] The assembly according to the invention is advantageously and optionally supplemented by the following features, taken alone or in any of their technically possible combinations:

[0022] - The assembly includes a cryogenic fuel storage tank in the state liquid.

[0023] - The assembly includes a regulating valve, designed to allow in the first operating mode one passage of cryogenic fuel in liquid state from the storage tank to the cryogenic pipeline and capable of blocking in the second operating mode the passage of cryogenic fuel in liquid state from the storage tank to the cryogenic pipeline so as to isolate the cryogenic pipeline from the storage tank.

[0024] - The assembly includes a purge valve, suitable for allowing in the second operating mode: the release of cryogenic fuel in gaseous state from the cryogenic pipeline to the outside.

[0025] - The first operating mode is a normal operating mode.

[0026] - The second operating mode is an operating mode of maintenance, preferably maintenance prior to inerting.

[0027] - The arm and forearm are connected by a joint. Thus, the passage of The transition from the first position to the second position is done in a simple manner.

[0028] - The joint allows the forearm to move from the first position to the second position and vice versa, from the second position to the first position.

[0029] - The joint only provides a pivot connection between the arm and the forearm. Thus, the articulation is particularly simple.

[0030] - The cryogenic pipeline, and preferably the storage tank, are arranged in a thermally insulated enclosure, preferably under partial vacuum. Thus, in the first operating mode, heat losses are limited.

[0031] - The forearm is entirely contained within the housing. Thus, the mobility of The forearm is made in a simple way, while avoiding heat loss.

[0032] - The joint is entirely disposed within the housing. Thus, the mobility of The forearm is made in a simple way, while avoiding heat loss.

[0033] - The second end of the arm is positioned outside the enclosure. Thus, the contribution The heat treatment is particularly easy to apply to the arm.

[0034] - The heat input is provided by the ambient air and / or by a heat source, of Preferably, an internal heat source within the aircraft engine is used. This avoids the need for additional electrical energy to provide heat. In the case of a heat source, this increases the heat output and reduces the time required for the cryogenic fuel to vaporize from its liquid state in the cryogenic piping.

[0035] - The forearm is formed by a rod leading to the joint. Thus, the forearm is accomplished in a particularly simple way.

[0036] - The forearm has a cover designed to come into contact with the pipe cryogenic when the forearm is in the second position. This increases the contact surface and heat transfer between the cryogenic channel and the forearm.

[0037] - The hood is positioned at a free end of the forearm, opposite the arm. Thus, The structure of the heating device is simple while optimizing the heat input in the second operating mode.

[0038] - The hood is disposed at a free end of the forearm opposite the joint. Thus, the structure of the heating installation is simple while optimizing the heat input in the second operating mode.

[0039] - The hood is entirely disposed within the enclosure. Thus, the mobility of the front- The arm is made in a simple way, while avoiding heat loss.

[0040] - The hood forms a dome of complementary shape with the pipe cryogenic. Thus, in the second position of the forearm, the contact surface is particularly large between the hood and the cryogenic channel and the heat transfer between the cryogenic channel and the forearm is increased.

[0041] - The heating installation includes a transfer enhancement device thermal. Thus, in the second operating mode, heat transfer is increased.

[0042] - The heat transfer enhancement device is located on the forearm and / or on the hood. Thus, in the second operating mode, heat transfer is increased in a simple way.

[0043] - The heat transfer enhancement device includes fins. Thus, the heat transfer enhancement device is made in a particularly simple way.

[0044] - The fins are retractable so as to be retracted into the first position and to to be deployed in the second position. Thus, the caloric intake is increased in the second position and reduced in the first position.

[0045] - The fins are attached to the forearm or to the hood.

[0046] - The fins are arranged between the joint and the cryogenic channel. Thus, The space required for the fins is limited.

[0047] - The fins are attached to one face of the hood opposite the pipe cryogenic. Thus, the heat input by radiation is increased.

[0048] - The heat transfer enhancement device comprises at least one heat pipe placed in the forearm or upper arm. This increases calorie intake.

[0049] - The heat pipe is formed by a closed tubular circuit.

[0050] - The heat pipe contains a heat transfer fluid.

[0051] - The heat transfer fluid is hydrogen or is neutral, preferably is helium, neon, or nitrogen. Thus, the heat transfer fluid cannot react with the cryogenic fuel, while being optimal in terms of heat transfer.

[0052] - The cryogenic conduit includes a stop against which the forearm rests finds support in the second position. Thus, contact between the forearm in the second position and the cryogenic channel is achieved in a simple and safe manner, without risk of damage to the forearm or the cryogenic channel.

[0053] - The assembly includes a vaporization exchanger. Thus, such an exchanger of Vaporization is suitable for supplying the aircraft engine, particularly its combustion chamber, with cryogenic fuel in a gaseous state.

[0054] - The vaporization exchanger is suitable for vaporizing the cryogenic fuel at the liquid state into a cryogenic fuel in the gaseous state in the first operating mode to supply the aircraft engine with cryogenic fuel in the gaseous state, the cryogenic piping allowing the passage of cryogenic fuel in the liquid state to the vaporization exchanger.

[0055] - The purge valve is mounted downstream of the cryogenic pipeline relatively to the storage tank.

[0056] - The purge valve is mounted upstream of the vaporization exchanger.

[0057] - Cryogenic fuel is liquefied natural gas or liquid hydrogen.

[0058] - The forearm is controlled manually or is motorized.

[0059] - The cryogenic pipeline is made of metal, preferably steel, more preferably in stainless steel. Such a material has the advantage of being resistant to very low temperatures and to any potential chemical action of cryogenic fuel, while also being a good thermal conductor.

[0060] - The arm is made of metal, preferably steel or copper. Such a material presents the advantage of being a good thermal conductor.

[0061] - The forearm is made of metal, preferably steel or copper. Such a material It has the advantage of being a good thermal conductor.

[0062] - The assembly includes at least one anti-radiation deflector disposed between The forearm and the cryogenic channel are exposed when the forearm is in the first position. Thus, heat input is limited when the forearm is in the first position.

[0063] - The assembly includes several heating installations. The number The number of heating systems, and therefore the number of arms, required depends on the heat input needed to vaporize the cryogenic fuel. This requirement depends on the system's heat losses in the first operating mode. If the heat losses are very low, the system may require several heating systems.

[0064] According to a second aspect, the invention also proposes an aircraft engine, remarkable in that it comprises a combustion chamber supplied with cryogenic fuel and an assembly as previously described.

[0065] The aircraft engine according to the invention is advantageously and optionally supplemented by the following features, taken alone or in any of their technically possible combinations:

[0066] - The cryogenic fuel is suitable for vaporization before injection into the chamber combustion.

[0067] - The aircraft engine is a turbomachine.

[0068] According to a third aspect, the invention proposes an aircraft, remarkable in that it includes at least one aircraft engine as previously described.

[0069] According to a fourth aspect, the invention proposes a maintenance method for an assembly as previously described, which is particularly advantageous for the purpose of reducing the environmental impact of aircraft such as airplanes, and thus comprises the following successive steps: - close the regulating valve located between the cryogenic pipeline and the storage tank, - Optionally, open the drain valve, - move the forearm from the first position to the second position, - wait a predetermined time.

[0070] The assembly method according to the invention is advantageously and optionally supplemented by the following features, taken alone or in any of their technically possible combinations:

[0071] - The maintenance procedure includes the following step: introducing an inert gas in the cryogenic pipeline, preferably helium or nitrogen.

[0072] - The predetermined duration is between 2 minutes and 240 minutes, preferably between 10 and 40 minutes. This duration is advantageous because it reduces the time required before any maintenance operation that necessitates inerting the cryogenic pipeline. DESCRIPTION OF THE FIGURES

[0073] Other features, objectives and advantages of the invention will become apparent from the detailed description below, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings, given by way of non-limiting examples and on which: - [Fig.1] is a schematic top view of an aircraft equipped with an aircraft engine according to the invention; - [Fig.2] is a schematic view according to a first variant of an embodiment of a cryogenic fuel supply assembly for an aircraft engine, on which the forearm is in a first position; - [Fig.3A] is a schematic cross-sectional view of a detail of the assembly shown in [Fig.2], in which the forearm is in the first position;

[0074] - [Fig. 3B] is a schematic view similar to [Fig. 3A], the forearm being in a second position; - [Fig.4A] is a schematic cross-sectional view of a detail of a second variant embodiment of the assembly shown in [Fig.2], in which the forearm is in the first position; - [Fig.4B] is a schematic view similar to [Fig.4A], with the forearm in the second position;

[0075] - [Fig. 5A] is a schematic cross-sectional view of a detail of a third variant of the realization of the assembly shown in [Fig.2], in which the forearm is in the first position; - [Fig.5B] is a schematic view similar to [Fig.5A], with the forearm in the second position;

[0076] - [Fig. 6A] is a schematic cross-sectional view of a detail of a fourth variant of the realization of the assembly shown in [Fig.2], in which the forearm is in the first position; - [Fig.6B] is a schematic view similar to [Fig.6A], with the forearm in the second position;

[0077] - [Fig. 7A] is a schematic cross-sectional view of a detail of a fifth variant of the realization of the assembly shown in [Fig.2], in which the forearm is in the first position; - [Fig.7B] is a schematic view similar to [Fig.7A], with the forearm in the second position;

[0078] - Figure 8 schematically represents the steps of a maintenance process for a cryogenic fuel supply assembly for an aircraft engine conforming to any of the aforementioned embodiment variants.

[0079] Throughout the figures, similar elements are designated by identical reference numerals. DETAILED DESCRIPTION OF THE INVENTION

[0080] Fig. 1 schematically represents an aircraft 100, preferably an airplane, equipped with at least one aircraft engine 1, in the example shown, with two aircraft engines 1.

[0081] As shown in [Fig. 2], the aircraft engine 1 includes, in particular, a combustion chamber 3 supplied with cryogenic fuel and a cryogenic fuel supply assembly 5. Advantageously, the cryogenic fuel is vaporized before injection into the combustion chamber 3.

[0082] Preferably, the cryogenic fuel is liquefied natural gas or liquid hydrogen.

[0083] Advantageously, the assembly 5 includes a vaporization exchanger 6. In a first operating mode, the vaporization exchanger 6 is suitable for vaporizing cryogenic fuel in liquid form into cryogenic fuel in gaseous form, in order to allow its introduction into combustion chamber 3.

[0084] Preferably, the first operating mode is a normal operating mode.

[0085] Advantageously, the aircraft engine 1 is a turbomachine, such as a turbojet or a turboprop.

[0086] Assembly 5 comprises a cryogenic pipeline 7 and at least one heating installation 9. According to an alternative not shown, assembly 5 comprises several heating installations 9.

[0087] Advantageously, the cryogenic pipeline 7 is suitable for containing cryogenic fuel. In this cryogenic pipeline 7, the cryogenic fuel is in a liquid state in a first operating mode so as to supply the aircraft engine 1 and is suitable for being vaporized in a second operating mode.

[0088] Preferably, the second operating mode is a maintenance operating mode, preferably a maintenance mode before inerting.

[0089] Advantageously, the cryogenic pipeline 7 is made of metal, preferably steel, more preferably stainless steel.

[0090] Advantageously, the vaporization exchanger 6 is adapted to vaporize cryogenic fuel in its liquid state into cryogenic fuel in its gaseous state in the first operating mode to supply the aircraft engine 1, more specifically the combustion chamber 3, with cryogenic fuel in its gaseous state. The cryogenic pipeline 7 allows the passage of cryogenic fuel in its liquid state to the vaporization exchanger 6.

[0091] Advantageously, the assembly 5 includes a storage tank 11. The storage tank 11 is suitable for storing cryogenic fuel in liquid form.

[0092] Advantageously, the assembly 5 includes a control valve 13. Preferably, the control valve 13 is adapted to allow, in the first operating mode, the passage of cryogenic fuel in liquid form from the storage tank 11 to the cryogenic pipeline 7 and adapted to block, in a second operating mode, the passage of cryogenic fuel in liquid form from the storage tank 11 to the cryogenic pipeline 7 so as to isolate the cryogenic pipeline 7 from the storage tank 11.

[0093] Advantageously, the assembly 5 includes a pump 15 suitable for pumping cryogenic fuel in liquid form, in the first mode of operation, from the storage tank 11 and the regulating valve 13 to the cryogenic pipeline 7.

[0094] Advantageously, the assembly 5 includes a purge valve 17, suitable for allowing, in the second operating mode, the release of the cryogenic fuel at the gaseous state outside the cryogenic pipe 7 to the outside or to a storage tank (not shown).

[0095] Preferably, the purge valve 17 is mounted downstream of the cryogenic pipeline 7 relative to the storage tank 11.

[0096] Preferably, the purge valve 17 is mounted upstream of the vaporization exchanger 6.

[0097] Advantageously, the cryogenic pipeline 7 and preferably the storage tank 11 are arranged in a thermally insulating enclosure 19.

[0098] Preferably, the enclosure 19 is under partial vacuum.

[0099] Advantageously, the pump 15 is also arranged in the enclosure 19.

[0100] Advantageously, the assembly 5 includes an inert gas reservoir 21, which is connected to the cryogenic pipeline 7 by an inerting valve 23.

[0101] According to a first variant also shown in [Fig. 3A] and [Fig. 3B], the heating installation 9 comprises a fixedly mounted arm 25. By "fixed", it is necessary to understand fixed relative to the cryogenic pipe 7. At one end of the arm 25 extends a forearm 27 movable between a first position (shown in [Fig. 3A]) and a second position (shown in [Fig. 3B]).

[0102] Advantageously, the arm 25 is made of metal, preferably steel or copper.

[0103] Advantageously, the forearm 27 is made of metal, preferably steel or copper.

[0104] Preferably, the cryogenic pipe 7 is fixed in the enclosure 19 by support feet 28. These support feet 28 are fixed and thus provide a heat input to the cryogenic pipe 7 independently of the operating mode.

[0105] Advantageously, the arm 25 is distant from the cryogenic pipe 7. In the second mode of operation, the arm 25 is subjected to a heat input at a second end opposite to the first end.

[0106] Preferably, the second end of the arm 25 is disposed outside the enclosure 19.

[0107] Preferably, the heat input is provided by the ambient air (as shown) and / or by a heat source, preferably an internal heat source within the aircraft engine 1. Such an internal heat source is, for example, a component of an oil circuit or a component of a cooling circuit. Preferably, the component is a pipe or a heat exchanger.

[0108] Advantageously, in the first position shown in [Fig.3A], the forearm 27 is distant from the cryogenic channel 7 so that the forearm 27 and the cryogenic channel 7 are thermally insulated from each other.

[0109] Advantageously, in the second position shown in [Fig. 3B], the forearm 27 is in thermal conduction with the cryogenic channel 7 and is suitable for create a thermal bridge between the cryogenic pipe 7 and the arm 25 so as to vaporize the cryogenic fuel contained in the cryogenic pipe 7.

[0110] Advantageously, the arm 25 and the forearm 27 are connected to each other by a joint 29. Thus, the joint 29 allows the forearm 27 to move from the first position to the second position and vice versa, from the second position to the first position.

[0111] Preferably, the joint 29 only provides a pivot connection between the arm 25 and the forearm 27.

[0112] Advantageously, the forearm 27 is manually controlled or is motorized.

[0113] Preferably, the forearm 27 is formed by a rod leading to the joint 29.

[0114] Preferably, the forearm 27 is entirely disposed within the enclosure 19.

[0115] Preferably, the joint 29 is entirely disposed within the enclosure 19.

[0116] Advantageously, the heating installation 9 includes a heat transfer enhancement device 31.

[0117] Preferably, the heat transfer augmentation device 31 is disposed on the forearm 27 and / or in the arm 25.

[0118] Preferably, the heat transfer augmentation device 31 comprises at least one heat pipe disposed in the forearm 27 or in the arm 25, or even one heat pipe disposed in the forearm 27 and one heat pipe disposed in the arm 25. The heat pipe contains a heat transfer fluid. Advantageously, the heat transfer fluid is hydrogen or is neutral, preferably helium, neon, or nitrogen.

[0119] Advantageously, the heat pipe is formed by a closed tubular circuit.

[0120] According to an alternative not shown, the assembly 5 includes at least one anti-radiation deflector disposed between the forearm 27 and the cryogenic conduit 7 when the forearm 27 is in the first position.

[0121] A second embodiment of the assembly 5 is shown schematically in [Fig.4A] and [Fig.4B]. According to this second embodiment, the forearm 27 differs from the forearm 27 in the first embodiment in that it includes a cover 33.

[0122] In [Fig.4A], the forearm 27 is in the first position, and in [Fig.4B], the forearm 27 is in the second position.

[0123] Advantageously, the hood 33 is disposed at a free end of the forearm 27, opposite the arm 25. In other words, the hood 33 is disposed at a free end of the forearm 27 opposite the joint 29.

[0124] Preferably, the hood 33 is entirely disposed within the enclosure 29.

[0125] Advantageously, the hood 33 forms a dome of complementary shape with the cryogenic channel 7.

[0126] Advantageously, the hood 33 is suitable for coming into contact with the cryogenic channel 7 when the forearm 27 is in the second position.

[0127] A third embodiment of the assembly 5 is schematically represented in [Fig. 5A] and [Fig. 5B]. According to this third embodiment, the heat transfer enhancement device 31 comprises fins 35. Thus, according to this third embodiment, the hood 33 differs from the hood 33 of the second embodiment in that fins 35 are attached to the hood 33. Therefore, according to this embodiment, the heat transfer enhancement device 31 is located on the hood 33.

[0128] In [Fig.5A], the forearm 27 is in the first position, and in [Fig.5B], the forearm 27 is in the second position.

[0129] Preferably, the fins 35 are attached to a face of the hood 33 opposite the cryogenic channel 7. In other words, when the forearm 27 is in the second position, the hood 33 is in contact on one face with the cryogenic channel 7, and the fins 35 extend from an opposite face of the hood 33.

[0130] Advantageously, the fins 35 are fixed. Alternatively, and according to a variant not shown, the fins 35 are retractable so as to be retracted in the first position and deployed in the second position.

[0131] A fourth embodiment of the assembly 5 is shown schematically in [Fig. 6A] and [Fig. 6B]. According to this fourth embodiment, the cryogenic pipe 7 differs from the cryogenic pipe 7 according to the first embodiment in that it includes a stop 37.

[0132] In [Fig.6A], the forearm 27 is in the first position, and in [Fig.6B], the forearm 27 is in the second position.

[0133] Thus, according to this fourth variant, the forearm 27 is in contact with the stop 37 when the forearm 27 is in the second position.

[0134] Advantageously, the stop 37 has a groove 39, and the forearm 27 has a rib 41, the groove 39 receiving the rib 41 only when the forearm 27 is in the second position, so as to increase the contact area between the forearm 27 and the cryogenic channel 7.

[0135] A fifth embodiment of the assembly 5 is schematically represented in [Fig. 7A] and [Fig. 7B]. According to this fifth embodiment, the heat transfer enhancement device 31 has fins 35. Thus, according to this fifth embodiment, the forearm 27 differs from the forearm 27 of the fourth embodiment in that fins 35 are attached to the forearm 27. Therefore, according to this embodiment, the heat transfer enhancement device 31 is located on the forearm 27.

[0136] In [Fig.7A], the forearm 27 is in the first position, and in [Fig.7B], the forearm 27 is in the second position.

[0137] Advantageously, the fins 35 are arranged between the joint 29 and the cryogenic channel 7.

[0138] Advantageously, the fins 35 are retractable so as to be retracted in the first position and deployed in the second position. Alternatively, and according to a variant not shown, the fins 35 are fixed.

[0139] Figure 8 represents the main steps of a maintenance process for a set 5 as previously described.

[0140] Such a maintenance procedure comprises the following steps: - P10 close the regulating valve 13 located between the cryogenic pipeline 7 and the storage tank 11, - P20 Optionally, open the purge valve 17, - P30 move the forearm 27 from the first position to the second position, - P40 wait a predetermined duration.

[0141] Advantageously, the predetermined duration is between 2 minutes and 240 minutes, preferably between 10 minutes and 40 minutes.

[0142] Preferably, the maintenance procedure further includes the following step: - P50 introduce an inert gas into the cryogenic pipeline 7. Step P50 is an inerting step and the introduction of the inert gas can in particular be carried out from an inert gas reservoir 21, which is connected to the cryogenic pipeline 7 by an inerting valve 23.

[0143] Once this inerting step has been carried out, an operator can perform a maintenance operation without risk.

[0144] The invention is not limited to the embodiments and variants shown, and other embodiments will be obvious to those skilled in the art. In particular, it is possible to combine the embodiments and variants with each other.

Claims

Demands

1. A cryogenic fuel supply assembly (5) for an aircraft engine (1), characterized in that it comprises: - a cryogenic pipeline (7) adapted to contain cryogenic fuel, in which the cryogenic fuel is in a liquid state in a first operating mode so as to supply an aircraft engine (1) and is adapted to be vaporized in a second operating mode, - at least one heating installation (9) comprising a fixedly mounted arm (25), at one end of which extends a forearm (27) movable between a first position and a second position, the arm (25) being distant from the cryogenic pipeline (7) and being subjected to a heat input at a second end opposite to the first end, in the first position, the forearm (27) being distant from the cryogenic pipeline (7) such that the forearm (27) and the cryogenic pipeline (7) are thermally insulated from each other on the other hand,In the second position, the forearm (27) is in thermal conduction with the cryogenic pipe (7) and is suitable for creating a thermal bridge between the cryogenic pipe (7) and the arm (25) so as to vaporize the cryogenic fuel contained in the cryogenic pipe (7).

2. Assembly (5) according to claim 1, which includes a storage tank (11) for cryogenic fuel in liquid form.

3. Assembly (5) according to claim 2, which includes a control valve (13), adapted to allow in the first mode of operation a passage of cryogenic fuel in the liquid state from the storage tank (11) to the cryogenic pipeline (7) and adapted to block in the second mode of operation the passage of cryogenic fuel in the liquid state from the storage tank (11) to the cryogenic pipeline (7) so as to isolate the cryogenic pipeline (7) from the storage tank (11).

4. Assembly (5) according to any one of claims 1 to 3, which includes a purge valve (17), adapted to permit in the second mode operation involves the release of cryogenic fuel in gaseous form out of the cryogenic pipeline (7) to the outside.

5. Assembly (5) according to any one of claims 1 to 4, wherein the arm (25) and the forearm (27) are connected to each other by a joint (29), the joint (29) allowing the forearm (27) to move from the first position to the second position and vice versa, from the second position to the first position.

6. Assembly (5) according to any one of claims 1 to 5, wherein the cryogenic pipeline (7) is disposed in a thermally insulating enclosure (19).

7. Assembly (5) according to claim 6, wherein the enclosure (19) is under partial vacuum.

8. Assembly (5) according to claim 6 or 7, wherein the forearm (27) is entirely disposed in the enclosure (19).

9. Assembly (5) according to any one of claims 6 to 8 taken in combination with claim 5, wherein the joint (29) is entirely disposed in the enclosure (19).

10. Assembly (5) according to any one of claims 6 to 9, wherein the second end of the arm (25) is disposed outside the enclosure (19).

11. Assembly (5) according to any one of claims 1 to 10, wherein the forearm (27) has a hood (33) adapted to come into contact with the cryogenic conduit (7) when the forearm (27) is in the second position.

12. Assembly (5) according to claim 11, wherein the hood (33) forms a dome of complementary shape with the cryogenic conduit (7).

13. Assembly (5) according to any one of claims 1 to 10, wherein the forearm (27) is formed by a rod leading to the joint (29).

14. Assembly (5) according to claim 13, wherein the cryogenic channel (7) has a stop (37) on which the forearm (27) rests in the second position.

15. Assembly (5) according to any one of claims 1 to 14, wherein the warming installation (9) comprises a heat transfer augmentation device (31), which is disposed on the forearm (27).

16. Assembly (5) according to claim 15, wherein the heat transfer augmentation device (31) comprises fins (35).

17. Assembly (5) according to claim 16, wherein the fins (35) are retractable so as to be retracted into the first position and deployed into the second position.

18. Assembly (5) according to any one of claims 15 to 17, wherein the heat transfer augmentation device (31) comprises at least one heat pipe disposed in the forearm (27) or in the arm (25).

19. Aircraft engine (1), characterized in that it comprises a combustion chamber (3) supplied with cryogenic fuel and an assembly (5) according to any one of claims 1 to 18.

20. Aircraft (100), characterized in that it comprises at least one aircraft engine (1) according to claim 19.

21. Method for maintaining a cryogenic fuel assembly (5) of an aircraft engine (1), the assembly (5) comprising: - a storage tank (11) for cryogenic fuel in liquid form, - a cryogenic pipeline (7) adapted to contain cryogenic fuel, in which the cryogenic fuel is in liquid form in a first operating mode so as to supply an aircraft engine (1) and is adapted to be vaporized in a second operating mode, - a control valve (13), adapted to allow in the first operating mode the passage of cryogenic fuel in liquid form from the storage tank (11) to the cryogenic pipeline (7) and adapted to block in the second operating mode the passage of cryogenic fuel in liquid form from the storage tank (11) to the cryogenic pipeline (7) so as to isolate the cryogenic pipeline (7) from the storage tank (H),- at least one heating installation (9) comprising a fixedly mounted arm (25), at one end of which extends a movable forearm (27) between a first position and a second position, the arm (25) being distant from the cryogenic pipe (7) and being subjected to a heat input at a second end opposite to the first end, in the first position, the forearm (27) being distant from the cryogenic pipe (7) such that the forearm (27) and the, cryogenic piping (7) is thermally insulated from each other, in the second position, the forearm (27) being in thermal conduction with the cryogenic pipe (7) and being able to create a thermal bridge between the cryogenic pipe (7) and the arm (25) so as to vaporize the cryogenic fuel contained in the cryogenic pipe (7), the process being characterized in that it comprises the following steps: - P10 close the regulating valve (13) located between the cryogenic pipeline (7) and the storage tank (11), - P30 move the forearm (27) from the first position to the second position, - P40 wait a predetermined duration.

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