TURBOMACHINE KIT

Abstract

ASSEMBLY FOR TURBOMACHINE The invention relates to an assembly (10) for supplying an aircraft turbomachine comprising: a storage tank (16) for a cryogenic fuel comprising an external wall (18), a fuel circuit (20) intended to be connected to means (22) for supplying fuel to a turbomachine, an upstream end of said circuit (20) opening into the interior of the tank (16) to take liquid fuel from the tank (16), in which said fuel circuit (20) comprises at least one portion (24, 36, 38) carried by the external wall (18) of said tank (16). Figure for abstract: figure 1

Description

Title of the invention: TURBOMACHINE ASSEMBLY Technical field

[0001] The present disclosure relates to a cryogenic fuel aircraft assembly. It also includes an aircraft equipped with such an assembly. Prior art

[0002] Conventionally, a cryogenic fuel is a fuel that must be stored at extremely low temperatures to allow it to maintain a liquid state. Such a fuel is generally made by liquefying a gas such as hydrogen. Other gases can also be used. Cryogenics is used when the temperature is below -150°C.

[0003] Storage in liquid form makes it possible to significantly increase the density, thus allowing the storage of a larger quantity of fuel for a given tank volume. This problem is particularly important in aeronautics for obvious aerodynamic reasons: the larger the onboard volume, the greater the aerodynamic drag. It is therefore quite natural that gaseous fuels at ambient pressure and temperature are stored in the form of cooled liquid rather than compressed gas. To obtain a density close to that of a liquid, a gas must be compressed to several hundred bars. Tanks resistant to this pressure are extremely heavy and do not seem feasible for aeronautics.

[0004] Cryogenic fuels have the advantage of reducing pollutant emissions and therefore make it possible to reduce greenhouse gas emissions.

[0005] The cryogenic fuel tank comprises an insulated container to limit the amount of heat entering the tank. However, heat exchanges take place between the tank and the external environment, leading to heat from the external environment entering the tank containing liquid fuel and vaporizing a portion of it if it is stored at saturation. The gas formed accumulates and increases the pressure in the tank. However, this increase in pressure directly impacts the sizing and design of the tank and therefore its mass.

[0006] It is therefore essential to develop technological solutions aimed at limiting the increase in temperature of the liquid fuel while avoiding an increase in mass. Summary

[0007] For this purpose, a first assembly is proposed, in particular for aircraft. including:

[0008] - a storage tank for a cryogenic fuel comprising an external wall, - a fuel circuit intended to be connected to fuel supply means of a turbomachine, an upstream end of said circuit opening into the interior of the tank to take a sample of liquid fuel from the tank,

[0009] in which

[0010] - said fuel circuit comprises at least one portion carried by the external wall of said tank.

[0011] According to the invention, liquid fuel leaving the fuel tank circulates in said at least one portion so that the flow of liquid fuel circulating therein captures mainly the calories coming from the outside, which prevents the calories from entering the tank and heating the liquid fuel. The thermal drift, that is to say the increase in the temperature of the liquid fuel, is lowered relative to the prior art, which prevents an increase in the pressure in the tank and makes it possible to reduce the mass of the tank. Furthermore, the external calories are thus captured by said portion of the fuel circuit, which makes it possible to increase the temperature of the fuel intended for the fuel supply means of the turbomachine. The fuel is thus preheated for use in a combustion chamber, which is beneficial to the operation of the turbomachine.

[0012] Means for pressurizing the fuel of said at least one portion may advantageously be provided in order to compress the fuel circulating in said portion and destined for the engines. In this way, the liquid fuel is slightly pressurized so that the fuel remains liquid despite an increase in its temperature. The pressure may be between 1 and 12 bars.

[0013] According to another characteristic, said at least one portion surrounds the external wall of the tank. The term "surrounds" is used with reference to a portion which may surround all or part of the tank. In particular, the portion may completely surround the external wall or only part of it as will be apparent from reading the description made with reference to the figures.

[0014] Said at least one portion may comprise a first portion delimited internally by an inner wall and an outer wall. The fuel circulates between the two inner and outer walls which forms a space surrounding the tank. The fuel which circulates there captures the calories from the external environment thus preventing these from heating the fuel in the fuel tank. The fuel is then recovered at the top of the tank where it is directed by a pipe towards the downstream of the circuit. of fuel.

[0015] The outer wall may be surrounded by a thermal insulation layer which increases the thermal insulation of the first portion of fuel and limits the supply of calories to it.

[0016] The inner wall may form the outer wall of the cryogenic fuel storage tank.

[0017] Said at least one portion may comprise a second portion arranged inside the external wall of the tank. This second portion may be arranged in contact with the external wall of the tank so as to maximize the heat transfer between the wall and the flow in said second portion.

[0018] In another embodiment of the invention, said second portion may comprise a spiral conduit extending inside the external wall of the tank.

[0019] Said at least one portion may further comprise a third portion comprising a spiral conduit extending around the external wall of the tank. This third portion may be arranged in contact with the external wall of the tank so as to maximize the heat transfer between the wall and the flow in said second portion.

[0020] In another embodiment, a thermal insulation layer may be interposed between the spiral conduit of the third portion and the outer wall of the tank. The thermal insulation layer may have at least one indentation extending in a direction opposite to the outer wall. A thermal conductor, such as aluminum, may be arranged between the turns of the conduit of the third portion. A thermal insulation layer may externally surround said conduit.

[0021] The thermal insulation layer and / or the thermal conductor make it possible to direct the heat towards the third portion to transfer it to the flow of fuel circulating in said third portion.

[0022] Fins may be formed in either the second or third portion of the fuel circuit and more particularly in the spiral conduits.

[0023] The present disclosure also relates to a second assembly, in particular for aircraft, which can be taken independently or in combination with the previously mentioned characteristics relating to the first aforementioned assembly, the second assembly comprising:

[0024] - a storage tank for a cryogenic fuel comprising an external wall, - a fuel circuit intended to be connected to fuel supply means of a turbomachine, an upstream end of said circuit opening inside the tank to take liquid fuel from the tank,

[0025] in which

[0026] - said fuel circuit comprises a portion for liquefying the gaseous part of the fuel and extending inside the tank and in an upper part of the tank.

[0027] The fuel flow from the liquefaction portion indirectly captures calories that have entered the fuel tank by serving as a recondenser for the cryogenic fuel in the gaseous state.

[0028] Said liquefaction portion may comprise a serpentine conduit formed of a plurality of segments.

[0029] The segments may be connected to each other by thermally conductive fins.

[0030] The hot gas in contact with the segments and the cold fins is cooled and then recondensed in liquid form and then falls back into the liquid. The fuel flow from the liquefaction portion recovers heat, which is advantageous for subsequently supplying the fuel supply means of a turbomachine.

[0031] Said portion can extend in a substantially horizontal direction to best cover the evaporation surface of the liquid.

[0032] The present disclosure also relates to a third assembly, in particular for aircraft, which can be taken independently or in combination with the previously mentioned characteristics relating to the first or second assembly mentioned above, the third assembly comprising:

[0033] - a storage tank for a cryogenic fuel, - a fuel circuit intended to be connected to fuel supply means fuel of a turbomachine, an upstream end of said circuit opening inside the tank to take a sample of liquid fuel from the tank,

[0034] in which

[0035] - the fuel tank comprises an inner wall and an outer wall together delimiting an annular space in fluid communication with an internal space via an orifice formed in the lower part of the inner wall, - the fuel circuit comprises a portion for liquefying the gaseous part of the fuel, this portion extending into an upper part of the annular space.

[0036] Said liquefaction portion may comprise a conduit with turns, for example two or three, one upstream end of which is connected by an external conduit to a lower part of the fuel tank and one downstream end of which is connected to a downstream part of the fuel circuit.

[0037] The tank has in this third assembly a double wall. The internal wall is preferably thermally insulating. The orifice formed at the bottom of the internal wall allows a quantity of liquid to pass into the annular space. The liquid present in this space is heated by the thermal inlets and rises to a recondenser which is the liquefaction portion in which a flow of liquid fuel circulates.

[0038] A valve may be provided at the top of the tank to lower the pressure in the annular space if it exceeds a threshold value, the gas then being discharged into the tank. For this, it may use a valve calibrated to a differential pressure of 0.1 to 0.2 bar, this valve being placed at the top of the tank. If the pressure between the two walls exceeds the pressure P=pressure in the tank +0.2 bar, the valve opens to release gas into the tank.

[0039] Each of the assemblies may comprise a multi-way valve mounted upstream of said portion of the conduit, between a fuel outlet of the tank and the upstream end of said portion of the conduit, an outlet of this multi-way valve being connected to the downstream of the fuel portion which may be one of the portions for capturing calories from outside the tank; that is to say one of the first portion, second portion and third portion; of the liquefaction portion mounted in the tank and of the liquefaction portion arranged in the annular space.

[0040] Also, the present disclosure relates to embodiments comprising one of the heat capture portions from outside the tank; i.e., one of the first portion, second portion, and third portion; the liquefaction portion mounted in the tank and the liquefaction portion arranged in the annular space. Thus, numerous embodiments are covered by the present disclosure.

[0041] In the present disclosure, the term "fuel circuit" refers to all or only part of the entirety of a fuel circuit supplying a turbomachine.

[0042] Also concerned is an aircraft such as an airplane comprising at least one of the assemblies described above, the cryogenic fuel storage tank being arranged in a rear part of the fuselage. Brief description of the drawings

[0043] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:

[0044] [Fig.l] is a schematic illustration of an aircraft assembly according to a first embodiment;

[0045] [Fig.2] is a schematic illustration of an aircraft assembly according to a second embodiment, this figure comprises: a part A named figure 2A illustrating the general principle of this second embodiment, a part B named figure 2B illustrating two variants of positioning of a portion of the fuel circuit relative to the fuel tank and a part C illustrating two variants of assembly of a portion of the fuel circuit around a fuel tank;

[0046] [Fig.3] is a schematic illustration of an aircraft assembly according to a third embodiment;

[0047] [Fig.4] is a schematic illustration of an aircraft assembly according to a fourth embodiment. Description of the embodiments

[0048] Reference is now made to the figures which illustrate several embodiments of the invention, [Fig.l] illustrates a first embodiment 10a of a first assembly 10 and [Fig.2] illustrates a second embodiment 10b of said first assembly 10, [Fig.3] illustrates a second assembly 12 and [Fig.4] illustrates a third embodiment 14.

[0049] In the first embodiment 10a illustrated in [Fig.l], the assembly 10 comprises a cryogenic fuel storage tank 16 comprising an external wall 18 and a fuel circuit 20 intended to be connected to fuel supply means 22 of a turbomachine (not shown), an upstream end of said fuel circuit opening into the interior of the tank 16 to take liquid fuel from the tank 16.

[0050] The fuel circuit 20 comprises a first portion 24 formed around the tank 16. This first portion 24 is delimited internally by an inner wall and by an outer wall 26. In the embodiment shown, the inner wall forms the outer wall 18 of the cryogenic fuel storage tank 16. That being said, in another embodiment, the inner wall of the first portion of the fuel circuit could be arranged at a distance from the tank, a thermal insulation layer being able to be interposed between this inner wall and the outer wall of the tank 16.

[0051] The first portion 24 of the fuel circuit is carried by the external wall and surrounds it so as to be able to capture the calories likely to enter the liquid fuel tank. The space formed by the external wall 18 of the tank 16 and the external wall 26 is fluidically connected to the fuel tank via a fuel outlet orifice 27 formed in a lower part of the external wall 18 of the tank 16 so that the fuel flows into the first portion 24 and then into the rest of the fuel circuit to supply the fuel supply means 22 of the turbomachine.

[0052] The outer wall is here surrounded by a thermal insulation layer 29 which allows to limit the intake of calories to the first portion 24 and therefore to the fuel in tank 16.

[0053] Pressurization means 28 are provided at the upstream end of the first portion and at the outlet of the tank. There is also a two-way valve 30 for diverting the fuel supply from the first portion 24 in the event of obstruction or damage to the latter. A bypass pipe 32 therefore connects the upstream end of the first portion 24 to the downstream end of the first portion 24. In this way, the fuel supply to the fuel supply means 22 is guaranteed. A pump 34 may also be provided between the downstream end of the pipe 32 and the fuel supply means 22.

[0054] In the second embodiment 10b illustrated in [Fig.2], the assembly 10 comprises a tank 18 and an external wall 18 and is connected to fuel supply means 22.

[0055] In this second embodiment, fuel pressurization means 28 are arranged at the outlet of a fuel sampling orifice 27 formed in a lower part of the external wall 18 of the fuel tank 16. The outlet of the pressurization means 28 is connected to a three-way valve, one outlet of which is connected to a pipe 32 for bypassing a second portion 36 or third portion 38 of the fuel circuit. In FIG. 2A, it is the third portion 38 which is illustrated and which is carried externally by the external wall 18 of the fuel tank 16. The second portion 36 and the third portion 38 here have the shape of a pipe with turns 36a, 38a which extend inside the tank 16 or around it.

[0056] When the third portion 38 is carried by the outer wall 18, the latter may be arranged in direct contact with the outer wall 18 so as to maximize the heat transfer between the outer wall and the fuel flow circulating in the third portion 38 of the fuel circuit. As illustrated in the upper part of FIG. 2B, the third portion 36 may have a semicircle shape in section. When the fuel circuit comprises a second portion, the latter is then carried by the outer wall and is arranged inside the tank and it may also have a semicircle shape in section. The second portion 36 of the fuel circuit and the third portion 38 of the fuel circuit may comprise heat transfer fins 40 making it possible to facilitate heat exchanges with the circulating fuel.

[0057] In an alternative embodiment, the third portion 38 of the fuel circuit may not be arranged in contact with the external wall as is visible in FIG. 2C (upper part and lower part).

[0058] As can be seen in Figure 2C, a thermal insulation layer 42 is interposed between the spiral conduit 38 and the external wall 18 of the tank 16 allowing block the transfer of calories to the tank 16. The coiled conduit 38 may be partly embedded in the thermal insulation layer 42. Furthermore, a thermal conductor 44, such as aluminum, may be arranged between the turns 38a of the coiled conduit 38 to direct the calories towards the coiled conduit 38. This effect is increased tenfold by the combination of a thermal insulation layer 42 in which the coiled conduit 38 is embedded and a thermal conductor 44 inserted between the turns. It should be noted that the external surface of the turns 38a may be free, the thermal conductor 44 not covering the turns 38a.

[0059] In a variant, the spiral conduit 38 and the thermal conductor 44 could be covered by a thermal insulation layer 46 which would make it possible to limit the supply of calories to the spiral conduit 38.

[0060] In a variant, the thermal insulation layer 42 in contact with the external wall 18 has at least one indentation 42a extending in a direction opposite to the external wall 18. This indentation 42a having the function of increasing the contact surface between the wall of the tank made of metallic material and the flow of liquid fuel to increase the heat transfer between the two.

[0061] We now refer to [Fig. 3] which represents a second assembly 12 whose assembly is substantially similar to that described with reference to FIG. 2A except for the circuit portion which is here of a different shape. Furthermore, the circuit 20 also comprises a circuit portion 48 which here ensures liquefaction of the gaseous part of the cryogenic fuel. This liquefaction portion 48 is connected to an outlet of the three-way valve 30. This liquefaction portion of the fuel circuit is arranged inside the tank and in an upper part thereof and is shaped so as not to extend into a liquid part of the tank 16.

[0062] The liquefaction portion comprises a coil conduit 48a formed of a plurality of segments 50 connected to each other by thermally conductive fins 52. The liquefaction portion 48 may extend in a substantially horizontal direction. It may be of substantially planar shape, that is to say that the segments 50 are all contained in the same plane.

[0063] [Fig. 4] illustrates a third and final assembly 14 according to the invention in which the fuel tank 16 comprises an internal wall 54 delimiting with the external wall 18 an annular space in fluid communication with an internal space 60 by an orifice 61 formed in the lower part of the internal wall 54. In this embodiment, the fuel circuit 20 comprises a liquefaction portion 62 of the gaseous part of the fuel formed in the annular space. For this, the liquefaction portion extends into an upper part of the annular space 60.

[0064] As illustrated, the liquefaction portion 62 comprises a spiral conduit 62a, one upstream end of which is connected by an external conduit 64 to a lower part of the tank. of fuel and of which a downstream end is connected to a downstream part of the fuel circuit 20.

[0065] The external conduit is connected to the outlet of the pressurization means 28 and to the inlet of the three-way valve 30. An outlet of the three-way valve is connected to the upstream end of the liquefaction portion 62 of the fuel circuit and another outlet is connected to a bypass pipe 32 of the liquefaction portion 62.

[0066] The separating boundary between liquid fuel and gaseous fuel in the annular space 60 is shown at 65.

[0067] It is understood that in each of the embodiments illustrated above, it would be possible to have passive insulation of the tank comprising for example foam and gel, so as to limit heat transfers into the ambient air. Furthermore, the fuel in the tank stored in the liquid state may be under pressure.

Claims

Claims

1. Assembly (10) for supplying an aircraft turbomachine comprising: - a storage tank (16) for a cryogenic fuel comprising an external wall (18), - a fuel circuit (20) intended to be connected to means (22) for supplying fuel to a turbomachine, an upstream end of said circuit (20) opening into the interior of the tank (16) to take liquid fuel from the tank (16), in which said fuel circuit (20) comprises at least one portion (24, 36, 38) carried by the external wall (18) of said tank (16), said at least one portion comprising a third portion (38) comprising a spiral conduit (38a) extending around the external wall (18) of the tank (16), a thermal conductor (44) being arranged between the turns (38a) of the conduit (38).

2. An assembly according to claim 1, wherein said at least one portion (24, 38) surrounds the outer wall (18) of the reservoir (16).

3. An assembly according to claim 1 or 2, wherein said at least one portion comprises a first portion (24) internally delimited by an inner wall (18) and an outer wall (26).

4. An assembly according to claim 3, wherein the inner wall forms the outer wall (18) of the cryogenic fuel storage tank (16).

5. An assembly according to one of claims 1 to 4, wherein said at least one portion comprises a second portion (36) arranged inside the external wall (18) of the reservoir (16).

6. An assembly according to claim 5, wherein said second portion (36) comprises a coiled conduit (36a) extending inside the outer wall (18) of the reservoir (16).

7. Assembly according to one of claims 1 to 6, in which a thermal insulation layer (42) is interposed between the conduit (38) and the external wall (18) of the tank (16).

8. An assembly according to claim 7, wherein the insulation layer thermal (42) has at least one indentation (42a) extending in a direction opposite to the external wall (18).

9. An assembly according to one of claims 7 or 8, wherein the thermal conductor (44) is aluminum.

10. Assembly according to one of claims 6 to 9, in which a thermal insulation layer (46) externally surrounds said conduit (38).

11. An assembly according to one of claims 1 to 10, wherein said at least one portion of the fuel circuit comprises fins (40) extending projecting therein.

12. Assembly according to one of claims 1 to 11, in which the fuel circuit (20) comprises a portion (48) for liquefying the gaseous part of the fuel, this portion (48) for liquefaction extending inside the tank (16) and in an upper part of the tank (16).

13. An assembly according to claim 12, wherein said liquefaction portion (48) comprises a serpentine conduit (48a) formed of a plurality of segments (50).

14. Assembly according to one of claims 1 to 13, in which the fuel tank comprises an internal wall (54) delimiting with the external wall (18) an annular space (60) in fluid communication with an internal space (60) by an orifice (61) formed in the lower part of the internal wall (54), the fuel circuit (20) comprising a portion (62) for liquefying the gaseous part of the fuel, this portion (62) extending into an upper part of the annular space (62).

15. An assembly according to claim 14, wherein said liquefaction portion (62) comprises a spiral conduit (62a) of which an upstream end is connected by an external conduit (64) to a lower part of the fuel tank (16) and of which a downstream end is connected to a downstream part of the fuel circuit.

16. Assembly according to one of the preceding claims, in which a multi-way valve (30) is mounted upstream of said portion of the conduit, between a fuel outlet of the tank (16) and the upstream end of said portion of the conduit.

17. Assembly according to one of the preceding claims, comprising means for pressurizing (28) the fuel of said at least one portion.

18. Aircraft such as an airplane comprising an assembly according to one of the preceding claims, the cryogenic fuel storage tank (16) being arranged in a rear part of the fuselage.

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