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: System for storing a cryogenic fuel configured to be carried on board an aircraft and method of using it Technical field

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

[0002] Climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various States. In particular, an ambitious standard applies both to new types of aircraft and those in circulation requiring the implementation of technological solutions in order to make them compliant with current regulations. Civil aviation has been mobilizing for several years now to make a contribution to the fight against climate change.

[0003] Technological research efforts have already made it possible to significantly improve the environmental performance of aircraft. The Applicant takes into consideration the impact factors in all phases of design and development to obtain less energy-intensive, more environmentally friendly aeronautical components and products 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 turbomachines powered by cryogenic fuels such as hydrogen. Such fuels are called cryogenic in that they are stored at very low temperatures, of the order of -253°C for hydrogen, to keep them in the liquid state. Hydrogen in the liquid state is in fact much denser than in the gaseous state, which allows it to be stored in cryogenic tanks of reduced volume and sized for low pressures, in particular below 10 bars.

[0005] In a known manner, the storage of cryogenic fuels is ensured by double-walled vacuum 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 inevitable thermal losses which tend to evaporate part of the liquid hydrogen, which has the effect of increasing the pressure in the tank. Cryogenic. During flight, the fuel extraction to power the turbomachine compensates for the increase in pressure linked to thermal losses and even tends to reduce the pressure in the cryogenic tank. In some cases, this requires injecting helium or hydrogen in gaseous state into the cryogenic tank to maintain a minimum pressure threshold.

[0006] During a stopover of the aircraft between two flights, the turbomachine is stopped and no longer draws fuel from the cryogenic tank, which no longer makes it possible to compensate for the increase in pressure linked to thermal losses. This results in a progressive increase in pressure in the cryogenic tank which must be controlled to comply with a maximum pressure threshold imposed by the dimensioning of the cryogenic tank. It is known in particular for this purpose to release to the outside a portion of the gaseous hydrogen contained in the cryogenic tank as soon as the pressure exceeds a threshold value, for example 5 bars. Such an operation, known to those skilled in the art under the term “degassing”, has the disadvantage of causing a loss of fuel which is undesirable from an environmental and economic point of view.

[0007] In practice, to delay the degassing operations, it would be possible to increase the size of the tank and provide a higher threshold value. This would, however, significantly increase the mass of the tank, which would undesirably penalize 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 taken 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 space-saving and inexpensive solution for delaying the degassing operations of cryogenic tanks of cryogenic fuel of aircraft turbomachines. The invention aims in particular to avoid degassing operations during stopovers lasting less than 12 hours, corresponding to extended night stopovers. PRESENTATION OF THE INVENTION

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

[0011] The invention advantageously makes it possible to slow down the increase in pressure due to thermal losses in a cryogenic tank on board an aircraft, in particular during a fuel sampling stop, when the aircraft is stopped on the ground. The invention advantageously makes it possible to activate the vibrating device to forcefully slosh the liquid phase of the cryogenic fuel. Such sloshing, known to those skilled in the art by the English term "sloshing", makes it possible to stir the liquid phase of the cryogenic fuel to homogenize its temperature. The liquid cryogenic fuel present at the walls of the tank, hotter due to thermal losses at the wall, is thus mixed with the colder one located in the center of the tank.This prevents the occurrence of a stratification phenomenon, namely the formation of a temperature gradient within the liquid phase with a higher temperature in contact with the wall and a lower temperature in the center of the tank. The vibrating device allows, in a low-energy and low-cost manner, to maintain the liquid cryogenic fuel at a homogeneous temperature to reduce its evaporation at the walls of the tank and thus limit the increase in the internal pressure of the cryogenic tank.

[0012] The use of so-called degassing operations, consisting of releasing part 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 lasting less than 12 hours, corresponding to extended night stopovers. This avoids an undesirable loss of fuel from an environmental and economic point of view. The vibrating device also has a compact architecture 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 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 the forced vibrations transmitted to the support structure. The elastically deformable device advantageously makes it possible to promote the vibration of the cryogenic tank operated 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 elastic deformation direction parallel to a predetermined vibration direction of the vibrating device. The elastically deformable device advantageously makes it possible to promote the vibration of the cryogenic tank 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 forcefully vibrate the cryogenic tank at a frequency of less than 10 kHz, preferably less than 5 kHz and preferentially less than 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 in the tank. The fins are preferably fixed. The fins are preferably positioned at the bottom of the tank. Such fins promote 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 forcefully vibrate the cryogenic tank in a rotational movement of the longitudinal axis.

[0018] The vibrating device advantageously makes it possible to generate a moment so as to cause the cryogenic tank to oscillate in rotation around its axis. This is sufficient to generate eddies and to promote heat exchanges in 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 a first 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 forcefully vibrate the cryogenic tank in a translational movement of a longitudinal axis.

[0020] The vibrating device thus makes it possible to oscillate the cryogenic tank in longitudinal translation. This is sufficient to generate eddies and to promote heat exchanges in 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 on 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 tank is in the form of a first cryogenic tank and a second cryogenic tank, and • the vibrating device mechanically connects the first cryogenic tank and the second cryogenic tank and is configured, when electrically powered, to forcefully vibrate the first cryogenic tank and the second cryogenic tank.

[0023] This makes it possible to reduce the size and limit the vibrations transmitted into 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 forcefully vibrate the first cryogenic tank and the second cryogenic tank in phase opposition. 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 duration, a step of supplying electricity to the vibrating device to forcefully vibrate the cryogenic tank, so as to increase the heat exchanges 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 comprises, 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 supplying electrical power to the vibrating device to forcefully vibrate the cryogenic tank in phase opposition with the external forces. PRESENTATION OF FIGURES

[0028] The invention will be better understood on reading the description which follows, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0029] [Fig.l] is a schematic representation in top view of a system for storing a cryogenic fuel according to a first embodiment of the invention.

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

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

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

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

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

[0035] [Fig.7] is a schematic representation in top view of a system for storing a cryogenic fuel 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 one embodiment of the invention.

[0037] [Fig.9] is a schematic cross-sectional representation of the storage system of [Fig.l] in which the cryogenic tank is driven in forced vibration to reduce the 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 for implementing the invention, said figures can of course be used 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 storage system 1 for a cryogenic fuel 100, adapted in particular for supplying one or more engines in a vehicle, and in particular 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 the 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 tank(s) 2, 2A, 2B and configured, when electrically powered, to drive the cryogenic tank(s) in forced vibration V, VA, VB genic 2, 2A, 2B, so as to increase the heat exchanges 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 comprise one or more support feet 5, 6, 7, 8 configured to be fixed to a support structure 20, 30 and comprising an elastically deformable device 4 configured to dampen the forced vibrations V, VA, VB transmitted to the support structure 20, 30.

[0040] The fuel 100 is said to be cryogenic in that it is stored in the cryogenic tank 2 at very low temperatures to maintain it in the liquid state, of the order of -253°C for hydrogen as an example. Despite the thermal insulation of the cryogenic tank 2, thermal losses tend to evaporate the cryogenic fuel 100, which has a density in the gaseous state that is much higher than that in the liquid state, which gradually increases the pressure in the cryogenic tank 2. The withdrawal of cryogenic fuel 100 to supply the aircraft turbomachines compensates for the increase in pressure linked to the thermal losses but only during their operation.

[0041] During a shutdown of the aircraft turbomachines, typically during a stopover between two flights, the invention advantageously makes it possible to activate the vibrating device 3, 3A, 3B to forcefully sloshing the liquid phase 101 of the cryogenic fuel 100. The vibrating device 3, 3A, 3B makes it possible, in a low-energy and low-cost manner, to stir 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 very exposed to thermal losses and therefore hotter, is mixed with the colder one located in the center of the tank 2. This makes it possible to reduce the thermal gradient of the liquid phase 101 of the cryogenic fuel, in other words to obtain 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 thermal losses. The use of so-called degassing operations, consisting of releasing part 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 lasting less than 12 hours, corresponding to extended night stopovers. This avoids an undesirable loss of fuel from an environmental and economic point of view. The vibrating device 3, 3A, 3B also has a compact architecture that is easy to integrate by mounting external on cryogenic tank 2.

[0043] The invention also makes it possible, during operation of the vehicle, in particular during flight of the aircraft, to limit the transmission of external forces to the cryogenic tank 2 by exerting vibrations in phase opposition 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 sized for the storage of a cryogenic fuel at very low temperatures and at low pressures, in particular below 10 bars. The cryogenic tank 2 typically comprises an inner wall 10 and an outer wall 11, preferably made of stainless steel, which preferably delimit 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 vacuum wall advantageously has low thermal conductivity to limit heat exchanges between the cryogenic fuel 100 and the exterior.

[0045] Still with reference to Figures 1 and 2, the cryogenic tank 2 preferably comprises a cylindrical body extending along the longitudinal axis Z terminated by convexly shaped ends 13, 14, for example hemispherical, semi-ellipsoidal or semi-ovoid. The cryogenic tank 2 preferably has a surface of revolution with a longitudinal axis Z, extending horizontally in this example. The ratio of the surface area of ​​the internal wall 10 to the internal volume of the cryogenic tank 2 is thus minimal, which reduces the heat exchanges between the cryogenic fuel 100 and the internal wall 10 of the cryogenic tank 2. It goes without saying that the cryogenic tank 2 could have another shape to allow its integration at the wings or in the hold of the aircraft.

[0046] Still with reference to Figures 1 and 2, the cryogenic tank 2 preferably comprises a fixing device 12, mounted on the external wall 11 of the cryogenic tank 2, on which the feet 5, 6, 9 are fixed. The fixing device 12 is preferably in the form of a frame surrounding the external 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 the stirring 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 alternatively or complementary comprises asperities. Such fins 19 and / or such asperities promote the stirring of the liquid cryogenic fuel.

[0048] According to a first embodiment illustrated in Figures 1 and 2, the reservoir 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 on the one hand fixed to the cryogenic tank 2, in this example to the fixing device 12, and on the other hand to the support structure 30, in this example the aircraft. The number of feet is equal to three so that the cryogenic tank 2 is isostatic.

[0049] Still with 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 axis Y, vertical in this example. The elastically deformable device 4 is for example 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] Still with 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, in a horizontally offset manner relative to the horizontal axis Z. The vibrating device 3 is configured to generate vibrations V in a predetermined vibration direction D3 extending parallel to the vertical axis Y. As illustrated in [Fig.2], this generates a moment which drives the cryogenic tank 2 in rotation R along the longitudinal axis Z in an oscillating movement, sufficient to form eddies in the liquid phase 101 of the cryogenic fuel 100. The moment is advantageously generated thanks to the offset position of the vibrating foot 9 relative to that of the elastically deformable devices 4 aligned along the longitudinal axis Z.

[0051] According to a preferred aspect, the vibrating device 3 is in the form of a controllable active 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 fortuitous external disturbances. The forced vibrations V preferably have a low frequency of less than 10 kHz, preferably less than 5 kHz and preferentially 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 movement around a neutral position. The electrical power supply is preferably provided by one or more batteries mounted on board the vehicle or externally on the ground. According to a preferred aspect, the batteries are recharged by a fuel cell powered by the cryogenic fuel 100 contained in the cryogenic tank 2.This advantageously makes it possible to recover the pressurized gas for recycling instead of releasing it by degassing.

[0052] [Fig. 3] illustrates a second embodiment of the invention distinguished from the first embodiment in that the feet 5, 6, 9 are 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, for example at the wing or the hold of an aircraft. The feet 21 of the envelope 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 but also the external disturbances supplied to the cryogenic tank 2 during operation of the vehicle.

[0053] [Fig. 4] illustrates a third embodiment of the invention distinguished from the first embodiment in that the cryogenic tank 2 comprises a third support foot 7 comprising an elastically deformable device 4, i.e. a number of feet 5, 6, 7, 9 equal to four. 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, in this example horizontal. The horizontal axis X extends orthogonally to the longitudinal axis Z and to the vertical axis Y. The vibrating device 3 advantageously makes it possible, when activated, to drive the cryogenic tank 2 in translation according to an oscillating movement of axis X, namely along its width, sufficient to form eddies in the liquid phase 101 of the cryogenic fuel 100.

[0054] [Fig. 5] illustrates a fourth embodiment of the invention distinguished 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 previously, the cryogenic tank 2 comprises three support feet 5, 7, 8 including a first support foot 5 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 makes it possible, when activated, to drive the cryogenic tank 2 in translation according to an oscillating movement of longitudinal axis Z, sufficient to form eddies in the liquid phase 101 of the cryogenic fuel 100.

[0055] [Fig. 6] illustrates a fifth embodiment of the invention distinguished from the fourth embodiment in that the vibrating device 3 is not mounted in a vibrating foot 9 of the cryogenic tank 2A, called “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 end 14, which reduces the 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 in a mirror image 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 makes it possible, when activated, to drive in translation both the first cryogenic tank 2A ​​and the second cryogenic tank 2B according to an oscillating movement of longitudinal axis Z. The vibrations V in the first cryogenic tank 2A ​​and the second cryogenic tank 2B are in phase.

[0056] [Fig. 7] illustrates a sixth embodiment of the invention distinguished from the fifth embodiment in that the first cryogenic tank 2A ​​and the second cryogenic tank 2B are connected together 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 ​​which are in phase opposition with 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 to the vehicle.

[0057] In each of the examples of 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 of [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 of FIGS. 1 to 7. The method of use comprises, when the aircraft is stopped on the ground OFF for a predetermined minimum duration, a step of electrically supplying El to the vibrating device(s) 3, 3A, 3B to cause the cryogenic tank(s) 2, 2A, 2B to undergo forced vibration V, VA, VB. The electrical supply step El is typically implemented during a stopover of an aircraft between two flights. The vibrations generated in the cryogenic tank 2 advantageously allow the low density cryogenic fuel 100 to be tossed in a controlled manner, which reinforces the heat exchanges in the liquid phase 101 and reduces the thermal gradient due to the heat losses from the cryogenic tank 2. The liquid phase 101 thus has a homogeneous temperature which reduces evaporation at the walls, and thus limits the increase in internal pressure in 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 comprises, when the aircraft is in ON operation: • a measurement step E2 of the external forces F transmitted to the cryogenic tank(s) 2, 2A, 2B and • if the external forces F are greater than a predetermined threshold S, a step of electrical supply E3 of the vibrating device(s) 3, 3A, 3B to cause forced vibration V, VA, VB of the cryogenic tank(s) 2, 2A, 2B in phase opposition 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 makes it possible, 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

Claims

1. Storage system (1) for a cryogenic fuel (100) configured to be carried on board 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 drive the cryogenic tank (2, 2A, 2B) into forced vibration (V, VA, VB) so as to increase the heat exchanges 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).

2. Storage system (1) according to claim 1, wherein the cryogenic tank (2, 2A, 2B) comprises at least one support foot (5, 6, 7, 8) configured to be fixed on a support structure (20, 30) and comprising at least one elastically deformable device (4) configured to dampen the forced vibrations (V, VA, VB) transmitted to the support structure (20, 30).

3. Storage system (1) according to claim 2, 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).

4. Storage system (1) according to one of claims 1 to 3, in which the vibrating device (3, 3A, 3B) is configured, when it is electrically powered, to drive forced vibration (V, VA, VB) of the cryogenic tank (2, 2A, 2B) at a frequency of less than 10kHz, preferably less than 5kHz and preferentially less than 1kHz.

5. Storage system (1) according to one of claims 2 to 4, wherein: • said at least one support leg (5, 6) is in the form of a first support leg (5) and a second support leg (6) 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) is configured, when electrically powered, to drive in forced vibration (V, VA, VB) the cryogenic tank (2, 2A, 2B) according to a rotational movement (R) of longitudinal axis (Z).

6. Storage system (1) according to one of claims 2 to 4, wherein: • the support foot (5) is mounted at a first end (13) of the cryogenic tank (2, 2A, 2B) extending along a longitudinal axis (Z), • the vibrating device (3, 3A, 3B) is mounted at a second end (14) of the cryogenic tank (2, 2A, 2B) and is configured, when electrically powered, to drive the cryogenic tank (2, 2A, 2B) in forced vibration (V, VA, VB) according to a translational movement along a longitudinal axis (Z).

7. Storage system (1) according to one of claims 1 to 6, wherein the cryogenic tank (2) comprises a vibrating foot (9) configured to be fixed on the support structure (20, 30) and comprising the vibrating device (3).

8. Storage system (1) according to one of claims 1 to 6, 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 connects the first cryogenic tank (2A) and the second cryogenic tank (2B) and is configured, when electrically powered, to drive forced vibration (V, VA, VB) of the first cryogenic tank (2A) and the second cryogenic tank (2B).

9. Storage system (1) according to claim 8, 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 in forced vibration (VA, VB) the first cryogenic tank (2A) and the second cryogenic tank (2B) in phase opposition.

10. Aircraft comprising a storage system (1) according to one of claims 1 to 9.

11. Method of using an aircraft according to claim 10, comprising, when the aircraft is stopped on the ground (OFF) for a predetermined minimum duration, a step of supplying electricity (El) to the vibrating device (3) to cause forced vibration (V, VA, VB) of the cryogenic tank (2, 2A, 2B), so as to increase the heat exchanges 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).

12. Method of use according to claim 11, 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 electricity (E3) to the vibrating device (3, 3A, 3B) to drive the cryogenic tank (2, 2A, 2B) in forced vibration (V, VA, VB) in phase opposition with the external forces (F).

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