Cryogenic fuel storage system configured for use on an aircraft and its method of use

Abstract

A cryogenic fuel (100) storage system (1) configured for onboard use in an aircraft and comprising: - at least one cryogenic tank (2) adapted to store the cryogenic fuel (100) in a liquid phase and in a gaseous phase, and - at least one vibrating device (3) mounted externally on the cryogenic tank (2) and configured, when electrically powered, to force the cryogenic tank (2) into vibration so as to increase heat exchange in the liquid phase to limit the evaporation of the cryogenic fuel (100) and thus lower the internal pressure of the cryogenic tank (2). Abstract figure: Figure 1

Description

Title of the invention: Cryogenic fuel storage system configured for onboard use in an aircraft and its method of use technical field

[0001] The present invention relates to the field of cryogenic fuel storage in an aircraft.

[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] This sustained research and development work focuses in particular on new generations of aircraft turbomachinery powered by cryogenic fuels such as hydrogen. Such fuels are called cryogenic because they are stored at very low temperatures, on the order of -253°C for hydrogen, to maintain them in a liquid state. Liquid hydrogen is indeed much denser than its gaseous state, which allows it to be stored in cryogenic tanks of small volume and designed for low pressures, particularly below 10 bar.

[0005] As is known, cryogenic fuels are stored in double-walled, vacuum-sealed cryogenic tanks, known to those skilled in the art as "super-insulated cryogenic tanks," which are carried on board the aircraft. Despite their very low thermal conductivity, such cryogenic tanks are subject to unavoidable heat losses that tend to evaporate some of the liquid hydrogen, thereby increasing the pressure in The cryogenic tank. During flight, fuel withdrawal to power the turbomachine compensates for the pressure increase due to heat loss and may even reduce the pressure in the cryogenic tank. This sometimes necessitates injecting helium or hydrogen in gaseous form into the cryogenic tank to maintain a minimum pressure level.

[0006] During a stopover between flights, the turbomachine is shut down and no longer draws fuel from the cryogenic tank, thus failing to compensate for the pressure increase due to heat loss. This results in a gradual rise in pressure within the cryogenic tank, which must be controlled to comply with a maximum pressure threshold imposed by the tank's design. One known method for this is to release a portion of the hydrogen gas contained in the cryogenic tank as soon as the pressure exceeds a threshold value, for example, 5 bar. This operation, known to those skilled in the art as "degassing," has the disadvantage of generating an undesirable fuel loss from both an environmental and economic perspective.

[0007] In practice, to delay degassing operations, it would be possible to increase the size of the tank and to use a higher threshold value. However, this would significantly increase the mass of the tank, which would undesirably negatively impact the performance of the turbomachine.

[0008] It is also known from application FR3113702A1 to provide a heat exchanger between the gaseous hydrogen and the liquid hydrogen drawn respectively from the top and bottom of the cryogenic tank. Such a system is, however, bulky and expensive.

[0009] The invention thus aims at a compact and inexpensive solution for delaying the degassing operations of cryogenic fuel tanks for aircraft turbomachinery. In particular, the invention aims to avoid degassing operations during stopovers of less than 12 hours, corresponding to extended overnight stopovers. PRESENTATION OF THE INVENTION

[0010] The invention relates to a cryogenic fuel storage system configured to be carried on board an aircraft, the storage system comprising: • At least one cryogenic tank suitable for storing cryogenic fuel in both a liquid and a gaseous phase, and • At least one externally mounted vibrating device on the cryogenic tank, configured, when electrically powered, to force the cryogenic tank into vibration in order to increase heat exchange in the liquid phase and limit evaporation of the cryogenic fuel and thus lower the internal pressure of the cryogenic tank.

[0011] The invention advantageously slows the pressure increase due to heat loss in a cryogenic tank onboard an aircraft, particularly during a fuel withdrawal stop when the aircraft is stopped on the ground. The invention advantageously activates the vibrating device to force the liquid phase of the cryogenic fuel into sloshing. This sloshing, known to those skilled in the art as "sloshing," mixes the liquid phase of the cryogenic fuel to homogenize its temperature. The liquid cryogenic fuel present at the tank walls, which is warmer due to heat loss through the walls, is thus mixed with the cooler fuel located in the center of the tank.This prevents the occurrence of stratification, namely the formation of a temperature gradient within the liquid phase, with a higher temperature at the wall and a lower temperature at the center of the tank. The vibrating device allows, in an energy-efficient and cost-effective manner, the maintenance of the liquid cryogenic fuel at a homogeneous temperature to reduce its evaporation at the tank walls and thus limit the increase in internal pressure within the cryogenic tank.

[0012] The use of so-called degassing operations, which consist of releasing a portion of the gaseous phase of the cryogenic fuel to the outside as soon as the pressure exceeds a threshold value, can advantageously be delayed or even avoided during stopovers of less than 12 hours, corresponding to extended overnight stops. This avoids an undesirable fuel loss from both an environmental and economic standpoint. Furthermore, the vibrating device has a compact design and is easily integrated by external mounting on the cryogenic tank. This can also make it possible to reduce the threshold value in order to reduce the mass of the tank carried on board the aircraft.

[0013] According to one aspect of the invention, the cryogenic tank comprises at least one support foot configured to be fixed to a support structure and comprising at least one elastically deformable device configured to dampen forced vibrations transmitted to the support structure. The elastically deformable device advantageously facilitates the vibration of the cryogenic tank by the vibrating device, while limiting the forces transmitted between the cryogenic tank and the support structure.

[0014] According to one aspect of the invention, the elastically deformable device comprises a predetermined direction of elastic deformation parallel to a predetermined direction of vibration of the vibrating device. The elastically deformable device advantageously facilitates the vibration of the cryogenic reservoir operated by the vibrating device, while limiting the forces transmitted between the cryogenic tank and the support structure.

[0015] According to one aspect of the invention, the vibrating device is configured, when electrically powered, to force the cryogenic tank into vibration at a frequency below 10 kHz, preferably below 5 kHz and preferably below 1 kHz. Low frequencies ensure sufficient sloshing of the liquid cryogenic fuel.

[0016] According to a preferred aspect of the invention, the storage system comprises a plurality of fins mounted internally within the tank. The fins are preferably fixed. The fins are preferably positioned at the bottom of the tank. Such fins promote the mixing of the liquid phase of the cryogenic fuel.

[0017] According to one aspect of the invention: • said at least one support foot is in the form of a first support foot and a second support foot mounted respectively at a first end and a second end of the cryogenic tank extending along a longitudinal axis, • the vibrating device is configured, when electrically powered, to drive the cryogenic tank into forced vibration in a longitudinal axis rotational motion.

[0018] The vibrating device advantageously generates a moment that causes the cryogenic tank to oscillate in rotation around its axis. This is sufficient to generate turbulence and promote heat exchange within the cryogenic tank because the cryogenic fuel has a low density.

[0019] According to one aspect of the invention: • The support foot is mounted at one end of the cryogenic tank extending along a longitudinal axis, • The vibrating device is mounted at a second end of the cryogenic tank and is configured, when electrically powered, to force the cryogenic tank into vibration along a longitudinal axis translational movement.

[0020] The vibrating device thus allows the cryogenic tank to oscillate in longitudinal translation. This is sufficient to generate turbulence and promote heat exchange within the cryogenic tank because the cryogenic fuel has a low density.

[0021] According to one aspect of the invention, the cryogenic tank comprises a vibrating foot configured to be fixed to the support structure and comprising the vibrating device. Such external mounting of the vibrating device is simple and practical.

[0022] According to one aspect of the invention: • said at least one cryogenic reservoir is in the form of a first cryogenic reservoir and a second cryogenic reservoir, and • The vibrating device mechanically links the first cryogenic tank and the second cryogenic tank and is configured, when electrically powered, to force vibration of the first cryogenic tank and the second cryogenic tank.

[0023] This makes it possible to reduce the bulk and limit the vibrations transmitted in the support structure.

[0024] According to one aspect of the invention, said at least one vibrating device is in the form of a first vibrating device and a second vibrating device configured, when electrically powered, to force the first cryogenic tank and the second cryogenic tank into vibration in opposite phase. This makes it possible to limit the vibrations transmitted into the support structure.

[0025] The invention also relates to an aircraft comprising a storage system as described above.

[0026] The invention also relates to a method of using an aircraft as described above, comprising, when the aircraft is stationary on the ground for a predetermined minimum time, a step of powering the vibrating device to drive the cryogenic tank into forced vibration, so as to increase heat exchange in the liquid phase to limit the evaporation of the cryogenic fuel and thus lower the internal pressure of the cryogenic tank.

[0027] According to one aspect of the invention, the method of use includes, when the aircraft is in operation, a step of measuring the external forces transmitted to the cryogenic tank and if the external forces are greater than a predetermined threshold, a step of powering the vibrating device to drive the cryogenic tank into forced vibration in opposition to the external forces. PRESENTATION OF THE FIGURES

[0028] 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.

[0029] Fig. 1 is a schematic top view representation of a cryogenic fuel storage system according to a first embodiment of the invention.

[0030] Figure [Fig. 2] is a schematic cross-sectional representation of the system of storage of the [Fig. 1] in which the cryogenic tank is driven into vibration forced to reduce the internal pressure of the cryogenic tank when the aircraft is stationary on the ground.

[0031] Fig. 3 is a schematic top view representation of a cryogenic fuel storage system according to a second embodiment of the invention.

[0032] Fig. 4 is a schematic top view representation of a cryogenic fuel storage system according to a third embodiment of the invention.

[0033] Fig. 5 is a schematic top view representation of a cryogenic fuel storage system according to a fourth embodiment of the invention.

[0034] Fig. 6 is a schematic top view representation of a cryogenic fuel storage system according to a fifth embodiment of the invention.

[0035] Fig. 7 is a schematic top view representation of a cryogenic fuel storage system according to a sixth embodiment of the invention.

[0036] Fig. 8 is a schematic representation of a method of using a storage system according to an embodiment of the invention.

[0037] Fig. 9 is a schematic cross-sectional representation of the storage system of Fig. 1 in which the cryogenic tank is driven into forced vibration to reduce external forces transmitted to the cryogenic tank when the aircraft is in operation.

[0038] It should be noted that the figures set out the invention in detail to implement the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0039] With reference to Figures 1 to 7, the invention relates to a cryogenic fuel storage system 100, adapted in particular for powering one or more engines in a vehicle, and especially one or more turbomachines in an aircraft. According to the invention, the storage system 1 comprises: • A cryogenic tank 2 (see Figures 1 to 5) or several cryogenic tanks 2A, 2B (see Figures 6 and 7) adapted to store cryogenic fuel 100 in a liquid phase 101 and in a gaseous phase 102, and • A vibrating device 3 (see Figures 1 to 6) or several vibrating devices 3A, 3B (see [Fig. 7]) mounted externally on the cryogenic tanks 2, 2A, 2B and configured, when electrically powered, to cause forced vibration V, VA, VB of the cryogenic tank(s) 2, 2A, 2B, so as to increase heat exchange in the liquid phase 101 to limit the evaporation of the cryogenic fuel 100 and thus lower the internal pressure of the cryogenic tank(s) 2, 2A, 2B, and • Preferably, the cryogenic tank(s) 2, 2A, 2B include one or more support feet 5, 6, 7, 8 configured to be fixed to a support structure 20, 30 and including an elastically deformable device 4 configured to dampen forced vibrations V, VA, VB transmitted to the support structure 20, 30.

[0040] Fuel 100 is described as cryogenic because it is stored in cryogenic tank 2 at very low temperatures to maintain it in a liquid state, on the order of -253°C for hydrogen, for example. Despite the thermal insulation of cryogenic tank 2, heat losses tend to evaporate the cryogenic fuel 100, which has a density much greater in its gaseous state than in its liquid state, thus progressively increasing the pressure in cryogenic tank 2. Withdrawing cryogenic fuel 100 to power aircraft turbomachinery compensates for the pressure increase due to heat losses, but only during their operation.

[0041] During a shutdown of aircraft turbomachinery, typically during a stopover between flights, the invention advantageously allows the vibrating device 3, 3A, 3B to be activated to forcefully agitate the liquid phase 101 of the cryogenic fuel 100. The vibrating device 3, 3A, 3B effectively and inexpensively mixes the liquid phase 101 of the cryogenic fuel 100 in the cryogenic tank 2 thanks to its low density. Thus, the cryogenic fuel 100 in contact with the wall of the tank 2, which is highly exposed to heat loss and therefore hotter, is mixed with the cooler fuel located in the center of the tank 2. This reduces the temperature gradient of the liquid phase 101 of the cryogenic fuel, in other words, results in a more homogeneous temperature. This limits the evaporation of cryogenic fuel 100 in tank 2, which limits the increase in internal pressure in cryogenic tank 2.

[0042] The invention thus makes it possible to slow down the increase in pressure in the cryogenic tank 2 due to heat losses. The use of so-called degassing operations, consisting of releasing a portion of the gaseous phase 102 of the cryogenic fuel 100 to the outside as soon as the pressure exceeds a threshold value, can advantageously be delayed or even avoided during stopovers of less than 12 hours, corresponding to extended overnight stopovers. This avoids an undesirable fuel loss of a From an environmental and economic point of view, the vibrating device 3, 3A, 3B also features a compact design and is easily integrated by external mounting on the cryogenic tank 2.

[0043] The invention also makes it possible, during the operation of the vehicle, in particular during the flight of the aircraft, to limit the transmission of external forces to the cryogenic tank 2 by exerting vibrations in opposite phase as will be described later.

[0044] With reference to Figures 1 and 2, the cryogenic tank 2, also known to those skilled in the art as a "super-insulated tank," is designed for storing cryogenic fuel at very low temperatures and pressures, in particular below 10 bar. The cryogenic tank 2 typically comprises an inner wall 10 and an outer wall 11, preferably made of stainless steel, which preferably define an intermediate space maintained under vacuum. The inner wall 10 and the outer wall 11 are preferably covered with one or more thermally insulating layers. Such a double wall under vacuum advantageously exhibits low thermal conductivity to limit heat exchange between the cryogenic fuel 100 and the outside.

[0045] With further reference to Figures 1 and 2, the cryogenic tank 2 preferably comprises a cylindrical body extending along the longitudinal axis Z, terminating in convex, for example hemispherical, semi-ellipsoidal, or semi-ovoid, ends 13, 14. The cryogenic tank 2 preferably has a surface of revolution with longitudinal axis Z, extending horizontally in this example. The ratio of the surface area of ​​the inner wall 10 to the internal volume of the cryogenic tank 2 is thus minimized, thereby reducing heat exchange between the cryogenic fuel 100 and the inner wall 10 of the cryogenic tank 2. It is understood that the cryogenic tank 2 could have another shape to allow its integration into the wings or the aircraft's cargo bay.

[0046] With further reference to figures 1 and 2, the cryogenic tank 2 preferably includes a fixing device 12, mounted on the outer wall 11 of the cryogenic tank 2, on which the feet 5, 6, 9 are fixed. The fixing device 12 preferably takes the form of a frame surrounding the outer wall 11, in this example along a vertical axis Y orthogonal to the longitudinal axis Z.

[0047] According to a preferred aspect illustrated in Figures 1 and 2, fins 19 are mounted in the cryogenic tank 2 to promote agitation of the liquid phase 101 of the cryogenic fuel 100. The fins 19 are preferably fixed. The fins 19 are preferably mounted at the bottom of the cryogenic tank 2. Preferably, the inner wall 10 has alternatively or complementary asperities. Such fins 19 and / or such asperities promote the mixing of the liquid cryogenic fuel.

[0048] According to a first embodiment illustrated in Figures 1 and 2, the cryogenic tank 2 comprises two support feet 5, 6 and a vibrating foot 9, in which the vibrating device 3 is mounted. Each of the feet 5, 6, 9 is fixed on one side to the cryogenic tank 2, in this example to the fastening device 12, and on the other side to the support structure 30, in this example the aircraft. The number of feet is three so that the cryogenic tank 2 is isostatic.

[0049] With further reference to Figures 1 and 2, the first support foot 5 and the second support foot 6 are mounted respectively at the first end 13 and the second end 14 of the cryogenic tank 2, along the longitudinal axis Z. Each support foot 5, 6 comprises an elastically deformable device 4 configured to deform elastically along a predetermined deformation direction D4 extending parallel to the Y-axis, which is vertical in this example. The elastically deformable device 4 may, for example, be in the form of one or more elements made of an elastomer or from braided metal wires, for example in the form of cushions.

[0050] With further reference to Figures 1 and 2, the vibrating foot 9 is positioned between the first end 13 and the second end 14 of the cryogenic tank 2, offset horizontally with respect to the horizontal axis Z. The vibrating device 3 is configured to generate vibrations V along a predetermined vibration direction D3 extending parallel to the vertical axis Y. As illustrated in [Fig. 2], this generates a moment that causes the cryogenic tank 2 to rotate R about the longitudinal axis Z in an oscillating motion, sufficient to create turbulence in the liquid phase 101 of the cryogenic fuel 100. The moment is advantageously generated by the offset position of the vibrating foot 9 relative to that of the elastically deformable devices 4 aligned along the longitudinal axis Z.

[0051] In a preferred aspect, the vibrating device 3 is in the form of an active, controllable device configured to generate forced vibrations V. The vibrations V are said to be forced, as opposed to free vibrations generated on the cryogenic tank 2 by accidental external disturbances. The forced vibrations V preferably have a low frequency of less than 10 kHz, preferably less than 5 kHz, and preferably less than 1 kHz. The vibrating device 3 is preferably in the form of a vibrating pot or a jack configured to move in an oscillating motion around a neutral position. The power supply is preferably provided by one or more batteries mounted on board the vehicle or externally on the ground. In a preferred aspect, the batteries are recharged by a fuel cell powered by the cryogenic fuel 100 contained in cryogenic tank 2. This advantageously allows the gas to be recovered under pressure for use instead of being released by degassing.

[0052] Figure 3 illustrates a second embodiment of the invention, differing from the first embodiment in that the feet 5, 6, 9 are fixed to a support structure 20 in the form of a casing, such as a housing, itself fixed by one or more feet 21 to the vehicle, for example, to the wing or cargo bay of an aircraft. The feet 21 of the casing 20 are preferably equipped with an elastically deformable device 4, as are the support feet 5, 6 of the cryogenic tank 2. This makes it possible to dampen the forced vibrations V transmitted to the vehicle as well as the external disturbances supplied to the cryogenic tank 2 during the operation of the vehicle.

[0053] Figure 4 illustrates a third embodiment of the invention, differing from the first embodiment in that the cryogenic tank 2 comprises a third support foot 7 including an elastically deformable device 4, resulting in a total of four feet 5, 6, 7, 9. The third support foot 7 is positioned opposite the vibrating foot 9. The predetermined vibration direction D3 of the vibrating device 3 and the predetermined deformation direction D4 of the elastically deformable devices 4 extend parallel to an axis X, which in this example is horizontal. The horizontal axis X extends orthogonally with respect to the longitudinal axis Z and the vertical axis Y. Advantageously, when activated, the vibrating device 3 drives the cryogenic tank 2 in translation along an oscillating motion about the axis X, namely along its width, sufficient to create turbulence in the liquid phase 101 of the cryogenic fuel 100.

[0054] Figure 5 illustrates a fourth embodiment of the invention, differing from the third embodiment in that the vibrating foot 9 is mounted at the second end 14 of the cryogenic tank 2, and the predetermined vibration direction D3 of the vibrating device 3 extends along the longitudinal axis Z. As before, the cryogenic tank 2 comprises three support feet 5, 7, 8, the first support foot 5 being mounted at the first end 13 of the cryogenic tank 2 opposite the vibrating device 3. The support feet 7, 8 are positioned laterally on either side of the cryogenic tank 2, preferably closer to the second end 14 than to the first end 13. The predetermined deformation direction D4 of each elastically deformable device 4 extends parallel to the longitudinal axis Z.The vibrating device 3 advantageously allows, when activated, the cryogenic tank 2 to be moved in translation along an oscillating motion with longitudinal axis Z, sufficient to create turbulence in the liquid phase 101 of the cryogenic fuel 100.

[0055] Figure 6 illustrates a fifth embodiment of the invention, which differs from the fourth embodiment in that the vibrating device 3 is not mounted in a vibrating foot 9 of the cryogenic tank 2A, referred to as the "first cryogenic tank 2A," but mechanically connects the first cryogenic tank 2A ​​to a second cryogenic tank 2B. The second cryogenic tank 2B extends along the longitudinal axis Z of the first cryogenic tank 2A. The first cryogenic tank 2A ​​and the second cryogenic tank 2B preferably extend in a mirror image along a plane transverse to the longitudinal axis Z. In this example, the vibrating device 3 is common to the first cryogenic tank 2A ​​and the second cryogenic tank 2B, mounted at their respective second ends 14, which reduces size and cost. Each cryogenic tank 2A, 2B has three feet which are support feet 5, 7, 8.The elastically deformable devices 4 of the first cryogenic tank 2A ​​are mounted as mirror images of those of the second cryogenic tank 2B, so that they all have a predetermined deformation direction D4 parallel to the longitudinal axis Z. The vibrating device 3 advantageously allows, when activated, both the first cryogenic tank 2A ​​and the second cryogenic tank 2B to be driven in translation along an oscillating motion about the longitudinal axis Z. The vibrations V in the first cryogenic tank 2A ​​and the second cryogenic tank 2B are in phase.

[0056] Figure 7 illustrates a sixth embodiment of the invention, differing from the fifth embodiment in that the first cryogenic tank 2A ​​and the second cryogenic tank 2B are connected by a first vibrating device 3A and a second vibrating device 3B, mounted in this example back-to-back along the longitudinal axis Z. The first vibrating device 3A is configured to generate vibrations VA in the first cryogenic tank 2A ​​that are in opposite phase to the vibrations VB generated by the second vibrating device 3B in the second cryogenic tank 2B. This ensures sufficient agitation in the cryogenic tanks while reducing the vibrations transmitted to the support structure 30, typically the vehicle.

[0057] In each of the examples in Figures 4, 5, 6, and 7, the feet 5, 6, 7, 8, 9 of the cryogenic tank(s) 2, 2A, 2B could alternatively be fixed to a support structure 20 in the form of an envelope, such as a casing, itself fixed by one or more feet 21 to the vehicle as in the example in [Fig. 3].

[0058] With reference to [Fig. 8], the invention also relates to a method of using an aircraft in which one or more storage systems 1 are mounted, as described in the examples in Figures 1 to 7. The method of use includes, when the aircraft is stationary on the ground OFF for a predetermined minimum duration, a power supply step E1 of the vibrating device(s) 3, 3A, 3B to Forced vibration is applied to the cryogenic tank(s) 2, 2A, 2B (V, VA, VB). The electrical power supply step (E1) is typically implemented during an aircraft's stopover between flights. The vibrations generated in the cryogenic tank 2 advantageously allow for controlled sloshing of the low-density cryogenic fuel 100, which enhances heat exchange in the liquid phase 101 and reduces the thermal gradient due to heat losses from the cryogenic tank 2. The liquid phase 101 thus has a homogeneous temperature, which reduces evaporation at the walls and therefore limits the increase in internal pressure within the cryogenic tank 2. Degassing operations can thus be delayed or even avoided.

[0059] According to a preferred aspect illustrated in Figures 8 and 9, the method of use also includes, when the aircraft is in ON operation: • a measurement step E2 of the external forces F transmitted to the cryogenic reservoir(s) 2, 2A, 2B and • if the external forces F are greater than a predetermined threshold S, an electrical supply step E3 of the vibrating device(s) 3, 3A, 3B to drive into forced vibration V, VA, VB the cryogenic tank(s) 2, 2A, 2B in opposite phase with the external forces F.

[0060] The measurement step E2 is typically carried out by an accelerometer 40, for example mounted at the feet of the cryogenic tank 2. The vibrating device 3 thus allows, according to a second function, to protect the cryogenic tank 2 during flight, by limiting the undesirable sloshing of the cryogenic fuel 100 due to external disturbances.

Claims

Demands

1. A cryogenic fuel (100) storage system (1) configured for onboard use in an aircraft, the storage system (1) comprising: • At least one cryogenic tank (2, 2A, 2B) adapted to store the cryogenic fuel (100) in a liquid phase (101) and in a gaseous phase (102), and • At least one vibrating device (3, 3A, 3B) mounted externally on the cryogenic tank (2, 2A, 2B) and configured, when electrically powered, to force vibration (V, VA, VB) of the cryogenic tank (2, 2A, 2B) so as to increase heat exchange in the liquid phase (101) to limit the evaporation of the cryogenic fuel (100) and thus lower the internal pressure of the cryogenic tank (2, 2A, 2B), • the cryogenic tank (2, 2A, 2B) comprising at least one first support foot (5) and a second support foot (6) configured to be fixed to a support structure (20,30) and comprising at least one elastically deformable device (4) configured to dampen forced vibrations (V, VA, VB) transmitted to the support structure (20, 30), the first support foot (5) and the second support foot (6) being mounted respectively at a first end (13) and a second end (14) of the cryogenic tank (2, 2A, 2B) extending along a longitudinal axis (Z), the vibrating device (3, 3A, 3B) being configured, when electrically powered, to drive the cryogenic tank (2, 2A, 2B) into forced vibration (V, VA, VB) in a rotational motion (R) about the longitudinal axis (Z).

2. Storage system (1) according to claim 1, wherein the elastically deformable device (4) has a predetermined elastic deformation direction (D4) parallel to a predetermined vibration direction (D3) of the vibrating device (3, 3A, 3B).

3. A storage system (1) according to any one of claims 1 and 2, wherein the vibrating device (3) is configured when fed electrically, to drive the cryogenic reservoir (2) into forced vibration (V) at a frequency below 10kHz, preferably below 5kHz and preferably below 1kHz.

4. Storage system (1) according to any one of claims 1 to 3, wherein fins (19) are mounted in the tank (2, 2A, 2B).

5. Storage system (1) according to any one of claims 1 to 4, wherein the cryogenic tank (2) includes a vibrating foot (9) configured to be fixed on the support structure (20, 30) and comprising the vibrating device (3).

6. Storage system (1) according to any one of claims 1 to 5, wherein: • said at least one cryogenic tank (2A, 2B) is in the form of a first cryogenic tank (2A) and a second cryogenic tank (2B), and • the vibrating device (3, 3A, 3B) mechanically links the first cryogenic tank (2A) and the second cryogenic tank (2B) and is configured, when electrically powered, to drive the first cryogenic tank (2A) and the second cryogenic tank (2B) into forced vibration (V, VA, VB).

7. Storage system (1) according to claim 6, wherein said at least one vibrating device (3A, 3B) is in the form of a first vibrating device (3A) and a second vibrating device (3B) configured, when electrically powered, to drive into forced vibration (VA, VB) the first cryogenic tank (2A) and the second cryogenic tank (2B) in opposite phase.

8. Aircraft comprising a storage system (1) according to any one of claims 1 to 7.

9. A method of using an aircraft according to claim 8, comprising, when the aircraft is stationary on the ground (OFF) for a predetermined minimum time, a step of powering (E1) the vibrating device (3, 3A, 3B) to drive the cryogenic tank (2, 2A, 2B) into forced vibration (V, VA, VB) in a rotational motion (R) about the longitudinal axis (Z), so as to increase heat exchange in the liquid phase (101) for limit the evaporation of the cryogenic fuel (100) and thus lower the internal pressure of the cryogenic tank (2, 2A, 2B).

10. A method of use according to claim 9, comprising, when the aircraft is in operation (ON), a step of measuring (E2) the external forces (F) transmitted to the cryogenic tank (2, 2A, 2B) and if the external forces (F) are greater than a predetermined threshold (S), a step of supplying power (E3) to the vibrating device (3, 3A, 3B) to drive into forced vibration (V, VA, VB) the cryogenic tank (2, 2A, 2B) in opposite phase with the external forces (F).

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