Cryogenic fuel circuit of an aircraft turbomachine

Abstract

The invention relates to an aircraft turbomachine (M) (A) comprising a fuel circuit (CC) including: - a liquid cryogenic fuel tank (10); - a primary distribution circuit (1) in fluidic communication with the tank; - a secondary distribution circuit (2) intended to be in fluidic communication with a combustion chamber (C) of the turbomachine (M); - a fluid heating device (3) comprising a fluid inlet (31) and a fluid outlet (32) in fluidic communication with the primary (1) and secondary (2) distribution circuits respectively, the heating device (3) being configured such that the cryogenic fuel changes from a liquid to a gaseous state when passing through the heating device (3), the cryogenic fuel being in a gaseous state at the fluid outlet in communication with the secondary distribution circuit (2). Figure 1

Description

Title of the invention: Cryogenic fuel circuit of an aircraft turbomachine

[0001] FIELD OF THE INVENTION AND PRIORITY OF THE TECHNOLOGY

[0002] The invention relates to a fuel circuit of a turbomachine. More particularly, it relates to a cryogenic two-phase fuel circuit, stored in liquid state and which can be transformed into a gas for injection into a combustion chamber of an aircraft engine turbomachine.

[0003] The fuel circuits integrated on aircraft turbomachinery are generally for liquid fuel, for example kerosene, the fuel being stored in liquid state in a fuel tank. However, such a fuel is very polluting. Description of the invention

[0004] The invention proposes a turbomachine comprising a fuel circuit which uses a fuel which is less polluting than a liquid fuel such as kerosene.

[0005] In this respect, the invention proposes, according to a first aspect, a turbomachine for an aircraft comprising a fuel circuit, said circuit comprising,

[0006] - a cryogenic fuel tank in liquid state;

[0007] - a primary distribution circuit in fluidic communication with the reservoir;

[0008] - a secondary distribution circuit intended to be in fluidic communication with a combustion chamber of the turbomachine,

[0009] - a fluid heating device comprising a fluid inlet fluid communication with the primary distribution circuit and a fluid outlet in fluid communication with the secondary distribution circuit,

[0010] the primary distribution circuit being configured to, during operation of the turbomachine, introduce a cryogenic fuel in liquid form into the heating device, the heating device being configured to heat the introduced cryogenic fuel in liquid form so that the cryogenic fuel changes from a liquid to a gaseous state when it passes through the heating device, the cryogenic fuel being in a gaseous state at the fluid outlet in communication with the secondary distribution circuit,

[0011] the primary distribution circuit, the secondary distribution circuit and the heating device being arranged relative to each other so that in a ground aircraft configuration, the heating device forms a low point relative to the primary distribution circuit and relative to the secondary distribution circuit.

[0012] The invention according to the first aspect is advantageously complemented by the following features, taken alone or in any technically possible combination thereof:

[0013] - the primary distribution circuit is inclined with respect to the horizontal axis when the aircraft is on the ground: at a non-zero negative angle so as to promote flow of liquid cryogenic fuel from the tank to the heating device; and at a non-zero positive angle so as to prevent stagnation or retention of gaseous cryogenic fuel in the secondary distribution circuit.

[0014] - the primary distribution circuit and the secondary distribution circuit extend respectively from the fluid inlet and fluid outlet in opposite directions.

[0015] - the primary distribution circuit and the secondary distribution circuit extend respectively from the fluid inlet and fluid outlet in the same directions.

[0016] - the reservoir and the primary distribution circuit include means thermal insulation, the means of thermal insulation including: an expanding insulating foam; a thermal blanket enveloping the tank and the primary distribution circuit.

[0017] - the primary distribution circuit comprises several pipes and fluidic connections, thermal insulation means including a double skin with partial vacuum around the pipes and encapsulation of the fluidic connections.

[0018] - the heating device includes a heat exchanger.

[0019] According to a second aspect, the invention relates to an aircraft comprising a turbomachine according to the first aspect of the invention, the aircraft comprising a fuselage and wings parallel to the ground when the aircraft is in ground configuration in particular in position.

[0020] According to a third aspect, the invention relates to an aircraft according to the second aspect of the invention, in which the fuel circuit is installed entirely or partially on the turbomachine.

[0021] According to one embodiment, the fuel circuit is installed in a wing or in the fuselage of the aircraft according to the third aspect of the invention. DESCRIPTION OF THE FIGURES

[0022] Other features, objectives and advantages of the invention will become apparent from the following description, which is purely illustrative and not limiting, and which should be read in conjunction with the accompanying drawings on which:

[0023] Fig. 1 illustrates a fuel circuit according to a first embodiment of the invention;

[0024] Figure [Fig. 2] illustrates a fuel circuit according to a second embodiment of the invention;

[0025] Figure 3 illustrates an aircraft comprising a fuel circuit according to the invention.

[0026] In all the figures, the similar elements relate to identical references. DETAILED DESCRIPTION OF THE INVENTION

[0027] Figures 1 and 2 illustrate a cryogenic fuel circuit CC of a turbomachine M of an aircraft A allowing to supply fuel to a combustion chamber C of an aircraft A.

[0028] The fuel circuit CC described herein allows a two-phase cryogenic fuel to be stored in a liquid state and injected into the combustion chamber C in a gaseous state.

[0029] A cryogenic fuel is a type of fuel that is stored at extremely low temperatures to keep it in a liquid state.

[0030] Such a fuel is preferably hydrogen, which is liquid at a temperature of approximately -253°C. Indeed, storing a fuel in a liquid state is more convenient than storing it in a gaseous state. Furthermore, using a cryogenic fuel such as hydrogen instead of a liquid fuel such as kerosene is less polluting.

[0031] The fuel circuit CC includes a tank 10 configured to store cryogenic fuel in liquid form, a primary distribution circuit 1 in fluidic communication with the tank 10, a secondary distribution circuit 2 intended to be in fluidic communication with the combustion chamber C of the turbomachine M of aircraft A, and a heating device 3 comprising a fluid inlet 31 in fluidic communication with the primary distribution circuit 1 and a fluid outlet 32 ​​in fluidic communication with the secondary distribution circuit 2.

[0032] The fuel circuit CC described herein is configured to, in operation of the turbomachine, introduce the cryogenic fuel in liquid form into the heating device 3. The heating device 3 is configured to heat the cryogenic fuel in liquid form introduced so that it changes from the liquid state to the gaseous state when it passes through the heating device 3, the cryogenic fuel being in the gaseous state at the outlet of fluid 31 in communication with the secondary distribution circuit 2 in fluidic communication with the combustion chamber C.

[0033] Such a DC fuel circuit therefore includes a so-called liquid zone in which the fuel circulates in liquid state and a so-called gaseous zone in which the cryogenic fuel circulates in gaseous state.

[0034] In such a DC fuel circuit, the natural flow of the fluid is antagonistic (downward for liquid and upward for gas). It follows that during normal operation and / or maintenance phases requiring cooling or purging of the fuel in the DC circuit, it is necessary to avoid the risk of high or low points in the DC circuit that could accumulate liquid or gaseous fuel. Indeed, this impairs the efficiency of rotating equipment (cavitation) and poses a risk of fire / leakage at the connections.

[0035] To achieve this, the primary distribution circuit 1, the secondary distribution circuit 2 and the heating device 3 are arranged relative to each other so that in a configuration of the aircraft stationary on the ground (in parking position on the tarmac in particular), the heating device 3 forms a low point relative to the primary distribution circuit 1 and relative to the secondary distribution circuit 2.

[0036] The low point corresponds to the point where the cryogenic fuel changes state.

[0037] The idea here is to promote the natural flow of the fuel in liquid or gaseous state. Liquid zone

[0038] The tank 10 is in particular equipped with a cooling system (not shown) to maintain it at a cryogenic temperature suitable for the fuel used.

[0039] The primary distribution circuit 1 is in fluidic connection with the tank 10 and with the fluid inlet 31 of the heating device 3. It advantageously includes a cryogenic pump 11, a filter 12 and a primary shut-off valve 13. These elements are functional at a cryogenic temperature, i.e., approximately -253 °C for hydrogen in the liquid state, and otherwise non-functional, as they do not allow control of the circulation of the liquid fuel in the primary distribution circuit 1.

[0040] When functional, the cryogenic pump 11 allows fuel to be pumped from the tank 10 at a given pressure.

[0041] The primary shut-off valve 13 allows control of the fuel flow in the primary distribution circuit 1 before it enters the heating device 3.

[0042] Advantageously, to avoid heat loss, the entire liquid zone is thermally insulated. Indeed, it is essential for the cryogenic fuel to flow into the primary distribution circuit 1 that it be maintained in a liquid state in this zone until the fluid inlet 31 of the heating device 3.

[0043] Such insulation prevents the capture of calories that would heat the liquid cryogenic fuel to avoid cavitation which would impair the operation of the pump 11 and increase the pressure in the event of non-cryogenic fuel temperature.

[0044] Thermal insulation can be done in several ways.

[0045] According to one embodiment, the reservoir 10 and the primary distribution circuit 1 can be encapsulated in a partially vacuum enclosure. Indeed, in the absence of air, thermal conductivity is low.

[0046] According to one embodiment, an insulating foam or a thermal blanket can encase the reservoir 10 and the primary distribution circuit 1. The insulating foam is, for example, a polyurethane foam and the thermal blanket is, for example, a rock wool or multi-layer glass wool.

[0047] The primary distribution circuit 1 comprises several pipes 14, the latter may be surrounded by a double skin with partial vacuum.

[0048] In addition, the encapsulation of the connections helps to complete the thermal insulation.

[0049] The primary distribution circuit 1 allows the cryogenic liquid fuel to be conveyed from the tank 10 to the heating device 3.

[0050] Thus, to facilitate the initial filling of the DC fuel circuit, it is important that the flow of cryogenic fuel occurs naturally, without suction or pressurization of the equipment, particularly the pump. Indeed, equipment such as the pump and valves operates at a cryogenic temperature (operating clearance at -253°C), therefore the circuit is filled with cryogenic fuel.

[0051] The primary distribution circuit 1 is inclined with respect to the horizontal axis XX when the aircraft A is on the ground by a non-zero negative angle α so as to promote a flow of the liquid cryogenic fuel from the tank 10 to the heating device 3. The angle α is at least, for example, 1°.

[0052] In particular, the primary distribution circuit 1 comprises primary pipes 14 which extend in a direction Y' from the fluid inlet 31 of the heating device 3. The angle a is taken between a horizontal direction Y extending from the fluid inlet 31 and the direction Y' along which the primary pipes 14 extend.

[0053] The idea is that the primary distribution circuit has a slope between the tank 10 and the heating device 3 when the aircraft is on the ground. The aircraft is on the ground in a parked position on the tarmac. Gaseous zone

[0054] The secondary distribution circuit 2 is in fluidic communication with the fluid outlet 32 ​​of the heating device 3 and the combustion chamber C of the aircraft turbomachine M.

[0055] The secondary distribution circuit 2 advantageously includes a flow valve 21 to control the flow of gaseous fuel and a secondary shut-off valve 23 to control the fuel flow in the secondary distribution circuit 2.

[0056] The secondary distribution circuit 2 allows the gaseous fuel from the heating device 3 to the combustion chamber C.

[0057] When emptying the circuit for maintenance, it is important that the gaseous fuel escapes naturally, without risk of stagnation or retention of gas pockets.

[0058] Thus, the secondary distribution circuit 2 is inclined with respect to the horizontal axis XX when the aircraft A is on the ground at a non-positive angle fi so as to prevent stagnation or retention of gaseous cryogenic fuel in the secondary distribution circuit 2.

[0059] In particular, the distribution circuit 1 includes secondary pipes 23 which extend in a direction Z” from the fluid outlet 32 ​​of the heating device 3. The angle fi is taken between a horizontal direction Z extending from the fluid outlet 32 ​​and the direction Z' along which the secondary pipes 15 extend.

[0060] The angle fi is at least, for example, 1°. Heating device 3

[0061] The heating device 3 therefore makes it possible to heat the liquid cryogenic fuel so that it changes into a gaseous state.

[0062] This is preferably a heat exchanger of a known type and will not be described further here.

[0063] The idea here is to position the heating device 3 relative to the primary and secondary distribution circuits so that it is at the lowest point when aircraft A is on the ground. Configuration examples

[0064] In [Fig. 1], the CC circuit forms a V, meaning that the primary distribution circuit 1 and the secondary distribution circuit 2 extend from the heating device 3 at opposite angles to the ground when the aircraft A is on the ground, with the heating device forming the lowest point of the circuit. According to this configuration, the primary 14 and secondary 15 lines extend from the fluid inlet 31 and fluid outlet 31, respectively, in opposite directions.

[0065] On [Fig.2] the CC circuit forms a U, that is to say that the primary distribution circuit 1 and the secondary distribution circuit 2 extend from the heating device 3, each forming a non-zero angle with respect to the ground when the aircraft A is on the ground in identical directions, the heating device 3 forming the lowest point of the circuit.

[0066] According to this configuration, the primary 14 and secondary 15 pipes extend respectively from the fluid inlet 31 and fluid outlet 31 in the same directions. This second configuration of [Fig. 2] has the advantage of being less bulky than the first configuration of [Fig. 1]. Furthermore, the liquid and gaseous zones can share support points in the aircraft A since they are located approximately in the same place. Aircraft

[0067] Fig. 3 schematically illustrates an aircraft A comprising a fuselage F and two engines M, each mounted under a wing W.

[0068] The above-described DC circuit can be mounted directly in the turbomachine M or in the fuselage F or in a cavity provided in or on the magnets W.

Claims

Demands

1. Turbomachine (M) of an aircraft (A) comprising a fuel circuit (CC), said circuit (CC) comprising: - a tank (10) of cryogenic fuel in liquid form; - a primary distribution circuit (1) in fluidic communication with the tank (11); - a secondary distribution circuit (2) intended to be in fluidic communication with a combustion chamber (C) of the turbomachine (M); - a fluid heating device (3) comprising a fluid inlet (31) in fluidic communication with the primary distribution circuit (1) and a fluid outlet (32) in fluidic communication with the secondary distribution circuit (2);the primary distribution circuit (1) being configured to, in operation of the turbomachine (M), introduce a cryogenic fuel in liquid form into the heating device (3), the heating device (3) being configured to heat the introduced cryogenic fuel in liquid form so that the cryogenic fuel changes from a liquid to a gaseous state when it passes through the heating device (3), the cryogenic fuel being in a gaseous state at the fluid outlet in communication with the secondary distribution circuit (2); the primary distribution circuit (1), the secondary distribution circuit (2) and the heating device (3) being arranged relative to each other so that in a ground configuration of the aircraft (A), the heating device (3) forms a low point relative to the primary distribution circuit (1) and relative to the secondary distribution circuit (2).

2. Turbomachine according to claim 1, wherein the primary distribution circuit (1) is inclined with respect to the horizontal axis (XX) when the aircraft (A) is on the ground: - by a non-zero negative angle (a) so as to promote the flow of liquid cryogenic fuel from the tank (10) to the heating device (3); and - of a non-zero positive angle ( / 1) so as to prevent stagnation or retention of gaseous cryogenic fuel in the secondary distribution circuit (2).

3. A system according to any one of claims 1 to 2 wherein the primary distribution circuit (1) and the secondary distribution circuit (2) extend respectively from the fluid inlet (31) and the fluid outlet (32) in opposite directions

4. System according to any one of claims 1 to 2, wherein the primary distribution circuit (1) and the secondary distribution circuit (2) extend respectively from the fluid inlet (31) and the fluid outlet (32) in the same directions.

5. System according to any one of claims 1 to 4, wherein the tank (10) and the primary distribution circuit (1) comprise thermal insulation means, the thermal insulation means comprising: - an expanding insulating foam; - a thermal blanket enveloping the tank (10) and the primary distribution circuit (1).

6. System one of the preceding claims, wherein the primary distribution circuit (1) comprises several pipes (14) and fluidic connections (15), the thermal insulation means comprising a double skin with partial vacuum around the pipes and encapsulation of the fluidic connections (15).

7. System according to any one of the preceding claims, wherein the heating device (3) comprises a heat exchanger.

8. Aircraft comprising a turbomachine according to any one of the preceding claims, aircraft (A) comprising a fuselage and wings parallel to the ground when aircraft (A) is in ground configuration in particular in position.

9. Aircraft according to the preceding claim, wherein the fuel circuit (CC) is installed wholly or partially on the turbomachine (M).

10. Aircraft according to claim 8, wherein the fuel circuit (CC) is installed in a wing (W) or in the fuselage (F).

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