System for supplying fluid fuel to a combustion chamber

Abstract

The invention relates to a system (17) for supplying fluid fuel to a combustion chamber (8), comprising: an inner pipe (18) for circulation of the fluid, an outer sheath (22) arranged coaxially around the inner pipe (18), an annular space (23) delimited by the outer sheath (22) around the inner pipe (18), and a valve (24) comprising a member that is movable between a first, open position in which the first inlet port (24c) is in fluidic communication with the outlet port (24d) and a second, closed position preventing fluidic communication between the inlet port (24c) and the outlet port (24d), and a control port (24e) fluidically connected to the annular space (23) such that the movable member is moved from the first position to the second position when the pressure in the annular space (23) is lower than the threshold pressure.

Description

[0001] DESCRIPTION

[0002] TITLE: COMBUSTIBLE FLUID SUPPLY SYSTEM FOR A COMBUSTION CHAMBER

[0003] Technical field of the invention

[0004] The invention relates to the field of systems for supplying combustible fluid, in particular dihydrogen, to a combustion chamber for an aircraft turbomachine.

[0005] The invention also relates to the field of turbomachines, in particular, twin-body turbojets comprising a combustion chamber supplied with combustible fluid, in particular dihydrogen.

[0006] Technical background

[0007] The state of the art is illustrated by documents US-A1-2022090709, EP-A2-2 664 766, US-A1-2015 / 0323188 and EP-A1-2 634 380.

[0008] An aircraft turbomachine, such as a twin-spool, twin-flow turbojet, typically comprises, from upstream to downstream in the direction of gas flow along a longitudinal axis, a fan rotatable about the longitudinal axis, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine and a gas exhaust nozzle. The turbomachine further comprises a system for supplying the combustion chamber with fuel, in particular a fuel such as kerosene. The supply system typically comprises a pipe having an internal fuel circulation passage and connected to the combustion chamber.

[0009] The blower allows the suction of an air flow divided for example into a primary flow and a secondary flow. The primary flow passes through a primary vein of the turbomachine delimited externally by an internal casing while the secondary flow is directed towards a secondary vein surrounding the primary vein.

[0010] The primary airflow is compressed within the compressors. Each compressor consists of a rotating disc and blades regularly distributed around the disc. The blades extend radially from the disc and compress the primary airflow.

[0011] The compressed air is then mixed with the fuel and burned in the combustion chamber. The gases from the combustion pass through the turbines. Each turbine has a mobile disc rotating around the longitudinal axis and blades regularly distributed around the disc. The blades extend radially from the disc and allow a force to be exerted on the gases from the combustion chamber. The gases finally escape through the nozzle, whose cross-section allows the acceleration of these gases to generate propulsion.

[0012] In order to limit the environmental impact of aircraft, it has been proposed to replace the kerosene used in the combustion chamber with green energy, in particular a combustible gas such as dihydrogen (H2). However, the current architecture of turbomachines does not allow the use of such a gas.

[0013] Indeed, during operation, there is a risk of one or more discs bursting, a phenomenon known by the English acronym UERF for "Uncontained Engine Rotor Failure". Such a burst can generate debris that can damage the combustion chamber duct and lead to hydrogen leaks. However, the hydrogen-air mixture, in a volume proportion of hydrogen between 13% and 65%, becomes detonating. Thus, given the gas flow rate of around 600g / s, the gas pressure of around 100 bars and the energy level involved in the duct, the bursting of at least one disc is likely to cause an explosion. Such an explosion represents a catastrophic event for the aircraft. Also, the hydrogen-air mixture, in a volume proportion of hydrogen between 4% and 75%, is flammable.

[0014] In order to avoid damaging the pipe and therefore limit the risk of explosion or fire in the turbomachine, it was considered to reinforce the internal casing with an annular reinforcement shield in order to contain the disc(s) in the event of a burst.

[0015] However, such a solution is not feasible in current turbomachine configurations. In particular, strengthening the internal casing would significantly penalize the turbomachine in terms of cost and mass. In addition, integrating such a reinforcement shield is not easy given the thickness required for such a shield to ensure its protective function.

[0016] Furthermore, in order to reduce the risks of explosion or fire in the event of a pipe rupture, the supply system is equipped with a valve that allows the pipe to be closed. The valve typically includes a gas inlet port and a gas outlet port connected to the pipe. In the open position of the valve, the inlet and outlet ports are in fluid communication so that the gas circulates in the pipe. When the bursting phenomenon of one or more discs is detected, an electronic signal is sent to the valve, which is placed in the closed position. In this position, the fluid cannot circulate between the inlet and outlet ports. The circulation of gas in the pipe is cut off, thus limiting the risks of air and gas mixing and therefore of explosion and / or fire.

[0017] However, this solution is not entirely satisfactory. Since the valve is electronically controlled, there is a delay between the detection of the disc bursting phenomenon and the valve closing. During this delay, gas circulates in the pipe and the risk of explosion or fire remains.

[0018] In this context, there is a need to reduce the risks of explosion and / or fire in a turbomachine comprising a system for supplying a combustion chamber with combustible gas, in particular dihydrogen, in an efficient, reliable, inexpensive manner and without impacting the mass of the turbomachine.

[0019] Summary of the invention

[0020] To this end, the invention proposes a system for supplying combustible fluid to a combustion chamber for an aircraft turbomachine, the supply system comprising:

[0021] - an internal conduit extending along an axis and comprising an internal passage for circulation of the combustible fluid.

[0022] The power system is remarkable in that it further includes:

[0023] - an external sheath arranged coaxially around the internal pipe,

[0024] - an annular space delimited by the external sheath around the internal pipe, the annular space being intended to be subjected to a threshold pressure, and

[0025] - a first valve comprising: a first inlet port for the combustible fluid, a outlet port for the combustible fluid fluidically connected to the internal passage, a member movable between a first open position in which the first inlet port is in fluid communication with the outlet port and a second closed position preventing fluid communication between the inlet port and the outlet port, and a control port fluidically connected to the annular space such that the movable member is moved from the first position to the second position when the pressure in the annular space is lower than the threshold pressure. The supply system comprises an internal conduit in which the combustible fluid circulates to supply the combustion chamber.

[0026] According to the invention, the supply system further comprises an outer sheath which defines with the inner pipe an annular space. The annular space has a threshold pressure. According to the invention, the supply system further comprises at least one hydraulic valve. The valve is of the normally closed (NC) type, and pneumatically controlled. By normally closed, it is understood that the valve is in a closed position, called a safety position, in the absence of pneumatic control, i.e. without gas pressure.

[0027] Indeed, the valve has a control port fluidly connected to the annular space. When the pressure in the annular space is equal to or greater than the threshold pressure, the movable member is in the first open position. In this position, the valve allows the flow of the combustible fluid. On the contrary, when the pressure in the annular space is lower than the threshold pressure, that is to say when the pressure in the annular space drops, the movable member is moved under the effect of the pressure variation, into the second position. In this position, the valve prevents the flow of the combustible fluid. The valve is then in the safety position.

[0028] Therefore, if the fuel system is damaged by debris generated during the bursting of a turbine or compressor disc, the outer sheath is ruptured so that the pressure in the annular space drops. Since the valve is controlled by the pressure variation in the annular space, it is then immediately placed in a safety position preventing the flow of combustible fluid in the internal pipe.

[0029] Thanks to the invention, the risks of explosion are therefore limited.

[0030] Also, the power supply system of the invention can be integrated into the turbomachine without significantly increasing its mass.

[0031] The invention may comprise one or more of the following features, taken in isolation from each other or in combination with each other:

[0032] - the internal pipe comprises a combustible fluid inlet section, a combustible fluid outlet section, and a central section located along the axis of the internal pipe between the inlet and outlet sections, the external sheath being arranged around the central section and the first valve being arranged between the inlet section and the external sheath,

[0033] - the annular space is filled with an inert gas such as nitrogen (N2),

[0034] - the threshold pressure is between 1 bar and 120 bar,

[0035] - a second valve comprising: a fuel fluid inlet port, a fuel fluid outlet port, a member movable between a first open position in which the inlet port is in fluid communication with the outlet port and a second closed position preventing fluid communication between the inlet port and the outlet port, and a control port fluidly connected to the annular space so that the movable member is moved from the first position to the second position when the pressure in the annular space is lower than the threshold pressure, the outer sheath being located between the first and second valves,

[0036] - the first valve comprises a second inlet port for an inert gas, the outlet port being in fluid communication with the second inlet port in the second closed position of the first valve,

[0037] - the second inlet port is fluidically connected to the annular space,

[0038] - the second inlet port is fluidically connected to an inert gas tank.

[0039] The invention also relates to a turbomachine for an aircraft, the turbomachine extending around a longitudinal axis and comprising from upstream to downstream:

[0040] - a low pressure compressor,

[0041] - a high pressure compressor,

[0042] - a combustion chamber,

[0043] - a high pressure turbine, and

[0044] - a low-pressure turbine. The turbomachine is remarkable in that it comprises a feed system according to any one of the preceding characteristics, the feed system being connected to the combustion chamber.

[0045] The turbomachine according to the invention may further comprise the following characteristics:

[0046] - the combustion chamber comprises an annular enclosure and an injector opening into the annular enclosure and connected to the internal pipe.

[0047] Brief description of the figures

[0048] Other characteristics and advantages will emerge from the following description of a non-limiting embodiment of the invention with reference to the appended drawings in which:

[0049] [Fig.1] Figure 1 is a schematic representation of an aircraft;

[0050] [Fig.2] Figure 2 is a schematic representation in longitudinal section of a half-turbomachine according to the invention and equipping the aircraft of Figure 1,

[0051] [Fig.3] Figure 3 is a schematic representation of a system for supplying fuel fluid to the combustion chamber equipping the turbomachine of Figure 2,

[0052] [Fig.4] Figure 4 is a functional schematic representation of the supply system of Figure 3 when the valve is in the open position,

[0053] [Fig.5] Figure 5 is a functional schematic representation of the supply system of Figure 3 when the valve is in the closed position, [Fig.6] Figure 6 is a functional schematic representation of the supply system according to one embodiment of the invention,

[0054] [Fig.7] Figure 7 is a functional schematic representation of the power supply system according to another embodiment of the invention, [Fig.8] Figure 8 is a functional schematic representation of the power supply system according to another embodiment of the invention. Detailed description of the invention

[0055] An aircraft 1 is for example shown in Figure 1. The aircraft 1 comprises a fuselage 2 and first and second wings 3 mounted on either side of the fuselage 2. The aircraft 1 further comprises at least two turbomachines 4 respectively secured to the first and second wings 3. With reference to Figure 2, the turbomachine 4 extends around and along a longitudinal axis X.

[0056] In the present application, the terms “upstream” and “downstream” are defined in relation to the direction of circulation of the gases in the turbomachine 4 along the longitudinal axis X, in particular from left to right in FIG. 1.

[0057] The terms “axial”, “axially”, “radial”, “radially”, are defined in relation to the longitudinal axis X of the turbomachine 4.

[0058] The terms "internal", "interior", "external", "exterior",

[0059] "externally" are defined relative to the distance from the longitudinal axis X along a radial axis perpendicular to the longitudinal axis X.

[0060] The turbomachine 4 is for example a turboprop, a single-flow or double-flow, single-spool or double-spool turbogenerator. The number of flows may be greater than two depending on the configuration of the turbomachine 4.

[0061] According to yet another example shown in Figure 2, the turbomachine 4 is a twin-spool, twin-flow turbojet. It comprises, from upstream to downstream, a fan 5, a low-pressure compressor 6, a high-pressure compressor 7, a combustion chamber 8, a high-pressure turbine 9, a low-pressure turbine 10, and a combustion gas exhaust nozzle 11.

[0062] The low-pressure and high-pressure compressors 6, 7 and the high-pressure and low-pressure turbines 9, 10 each comprise at least one centered bladed disc that can rotate about the longitudinal axis X. Advantageously, the turbomachine 1 further comprises an intercompressor casing 12 arranged axially between the low-pressure and high-pressure compressors 6, 7.

[0063] The low pressure compressor 6 and the low pressure turbine 10 are connected by a low pressure shaft 13 and together form a low pressure body. Preferably, the blower 5 is connected to the low pressure shaft 13, for example via a speed reducer.

[0064] The high-pressure compressor 7 is connected to the high-pressure turbine 9 by a high-pressure shaft 14 and together form a high-pressure body.

[0065] The blower 5 allows the suction of an air flow F dividing into a primary flow F1 and a secondary flow F2. The primary flow F1 flows in a primary vein v1 of the turbomachine 4 while the secondary flow F2 flows in a secondary vein v2 surrounding the primary vein v1.

[0066] The secondary vein v2 is delimited externally by an external casing 15 centered on the longitudinal axis X. The external casing 15 surrounds at least the fan 5 and preferably extends axially to the low-pressure turbine 9. The external casing 15 may be multi-piece. It may comprise a fan casing surrounding the fan 5 and a motor casing extending from the compressor 6 to the low-pressure turbine 9. The secondary vein v2 is delimited internally by an inter-vein casing 16.

[0067] The primary vein v1 is delimited externally by the inter-vein casing 16.

[0068] The combustion chamber 8 comprises an inner annular wall and an outer annular wall centered on the longitudinal axis X. The inner and outer annular walls are connected by a bottom wall. The combustion chamber 8 further comprises an annular enclosure 8a located between the inner and outer annular walls. The combustion chamber further comprises at least one injector 8b of combustible fluid opening into the annular enclosure 8a. The injector 8b passes for example through the bottom wall. The turbomachine 4 further comprises a system 17 for supplying combustible fluid to the combustion chamber 8.

[0069] The supply system 17 is connected to the combustion chamber 8. It comprises an internal pipe 18. The internal pipe 18 has an axis C. The internal pipe 18 extends for example radially in the turbomachine 4 and connects a source 19 of combustible fluid located for example in the wing 3 to the combustion chamber 8. The internal pipe 18 thus extends radially in the secondary vein v2.

[0070] The internal pipe 18 has an external diameter for example between 1 mm and 100 mm, preferably between 1 mm and 50 mm. The internal pipe 18 is advantageously made of a metallic material chosen for example from metallic alloys such as Inconel®, stainless steels, aluminums or from a polymeric material chosen for example from polyamides, polyolefins, fluorinated polymers or from a composite material.

[0071] The internal pipe 18 comprises an inlet section 18a for the combustible fluid and an outlet section 18b for the combustible fluid. The inlet section 18a is for example connected to the source 19 of combustible fluid. The outlet section 18b is for example connected to the combustion chamber 8 via the injector 8b for example. The internal pipe 18 further comprises a central section 18c located along the axis C of the internal pipe 18 between the inlet section 18a and the outlet section 18b. The internal pipe 18 comprises an internal passage 20 for circulation of the combustible fluid. Advantageously, the internal passage 20 extends from the inlet section 18a to the outlet section 18b. The combustible fluid thus circulates in the internal passage 20 from the inlet section 18a to the outlet section 18b. The pressure of the combustible fluid in the internal pipe 18 is for example less than 100 bar.

[0072] The combustible fluid is a gas or a liquid. The fluid is, for example, natural gas, also called fossil gas, methane (CH4), ammonia (NH3) or, more advantageously, dihydrogen (H2) in liquid or gaseous form.

[0073] In operation, the primary air flow F1 is compressed within the low-pressure and high-pressure compressors 6, 7. The air then circulates in the combustion chamber 8. In parallel, the combustible fluid circulates in the internal conduit 18 and is injected into the annular enclosure 8a of the combustion chamber 8 by the injectors 8b. The combustible fluid is mixed with the compressed air in the annular enclosure 8a of the combustion chamber 8 and combustion of the mixture is carried out. The gases resulting from the combustion then pass through the high-pressure and low-pressure turbines 9, 10 and then escape through the nozzle 11 to generate propulsion.

[0074] In operation, there is a risk that a disk, for example of the high-pressure turbine 6 or the low-pressure compressor 10, may burst. However, the internal pipe 18 is located in the disk burst zone Z1. In such a case, the debris generated may damage the internal pipe 18 and cause a leak of the combustible fluid. A leak of the combustible fluid, in particular dihydrogen, mixed with the air flow F2 of the secondary vein v2 may cause an explosion or a catastrophic fire for the aircraft 1 and / or the turbomachine 4.

[0075] In this context, with reference to Figure 3, according to the invention, the supply system 17 further comprises a safety system 21 comprising an external sheath 22, an annular space 23 and a first valve 24.

[0076] The outer sheath 22 is annular and is arranged coaxially around the inner pipe 18. Advantageously, the outer sheath 22 is arranged around the central section 18c. It is therefore located along the axis C of the inner pipe 18 between the inlet section 18a and the outlet section 18b. The outer sheath 22 thus extends throughout the bursting zone Z1.

[0077] The outer sheath 22 has an outer diameter for example between 1 mm and 200 mm, advantageously between 1 mm and 100 mm. The outer sheath 22 has a thickness for example between 1 mm and 100 mm, preferably between 1 mm and 50 mm, even more preferably between 1 mm and 10 mm. The outer sheath 22 is preferably made of a metallic material chosen for example from metal alloys such as Inconel®, stainless steels, aluminums or from a polymeric material chosen for example from polyamides, polyolefins, fluorinated polymers or from a composite material.

[0078] As can be seen schematically in Figure 4, the annular space 23 is located between the outer sheath 22 and the inner pipe 18. The annular space 23 is therefore delimited by the outer sheath 22 around the inner pipe 18. The annular space 23 has a thickness of between 1 mm and 50 mm.

[0079] The annular space 23 is sealed. The annular space 23 is pressurized. The pressure in the annular space is equal to a threshold pressure of between 1 bar and 120 bar. Advantageously, the threshold pressure is greater than the pressure of the combustible fluid in the internal pipe 18. Advantageously, the annular space 23 is filled with an inert gas. By inert gas, it is understood that the mixing of the inert gas with the air or with the gases resulting from the combustion does not cause any chemical reaction under the operating pressure and temperature conditions of the turbomachine 4. The inert gas is for example argon (Ar), helium (He), carbon dioxide (CO2) or preferably nitrogen (N2).

[0080] The first valve 24 is of the hydraulic or pneumatic type. According to the invention, the first valve 24 is pneumatically controlled. According to the invention, the first valve 24 is of the normally closed type also known by the acronym “NC”. In other words, the first valve 24 is in the closed position in the absence of pneumatic control.

[0081] With reference to Figure 4, the first valve 24 comprises a valve body 24a delimiting an internal chamber 24b for circulation of the combustible fluid. The first valve 24 further comprises a first inlet port 24c for the combustible fluid and an outlet port 24d for the combustible fluid. The first inlet port 24c and outlet port 24d open into the internal chamber 24b. The first inlet port 24c is for example connected to the internal passage 20 of the internal pipe 18 or to the source 19 of combustible fluid. The outlet port 24d is connected to the internal passage 20 of the internal pipe 18.

[0082] The first valve 24 further comprises a member movable between a first position and a second position.

[0083] The first valve 24 further comprises a control port 24e. According to the invention, the control port 24e is fluidically connected to the annular space 23. For example, a first control line 25a connects the control port 24e of the valve 24 to the annular space 23. Thanks to such a fluid connection between the valve 24 and the annular space 23, under the effect of the pressure variation in the annular space 23, the movable member is moved in the valve body 24a. Thus, the movable member is moved from the first position to the second position when the pressure in the annular space 23 is lower than the threshold pressure.

[0084] The first position is shown in Figure 4. It is an open position of the first valve 24. The first valve 24 is maintained in the first position as long as the pressure in the annular space 23 is at least equal to the threshold pressure. In this position, the first inlet port 24c is in fluid communication with the outlet port 24d. The combustible gas is thus allowed to flow into the first valve 24 and the internal passage 20.

[0085] When the pressure in the annular space 23 drops and becomes lower than the threshold pressure, the movable member is moved into the second position. The second position is shown in Figure 5. It is a position for closing the first valve 24 with respect to the circulation of the combustible fluid. In this second position, the fluid communication between the first inlet port 24c and the outlet port 24d is closed. The combustible fluid cannot circulate in the first valve 24 and therefore the internal passage 20. In the event of damage to the supply system 17 by debris generated during the bursting of a disc, the external sheath 22 is ruptured so that the pressure in the annular space 23 drops and becomes lower than the threshold pressure.The first valve 24 being controlled by the pressure variation in the annular space 23, the movable member is immediately moved into the second position, preventing the circulation of the combustible fluid in the internal passage 20 of the internal pipe 18.

[0086] Also, the rupture of the outer sheath 22 allows the release of the inert gas. The inert gas mixes with the combustible fluid present in the internal pipe 18 and allows the concentration of combustible fluid in the air to be reduced and therefore the risk of explosion to be limited.

[0087] The safety system 21 of the invention therefore makes it possible to considerably reduce the risk of explosion in the turbomachine 4 and / or the aircraft 1.

[0088] Preferably, the first valve 24 has a return spring 24f. The movable member is returned to the second position by the return force of the return spring 24f in the absence of pneumatic control, that is to say when the pressure is lower than the threshold pressure.

[0089] Preferably, the first valve 24 is arranged between the source 19 of combustible fluid and the external sheath 22.

[0090] According to a first exemplary embodiment illustrated in Figures 3 to 8, the first valve 24 is mounted around the internal pipe 18. According to this first example, the first inlet port 24c and the outlet port 24d are connected to the internal pipe 18, in particular to the inlet section 18a. According to this exemplary embodiment, the first valve 24 is arranged around the inlet section 18a, between the source 19 of combustible fluid and the external sheath 22.

[0091] According to a second exemplary embodiment not shown, the first valve 24 is arranged between the source 19 of combustible fluid and the internal pipe 18. According to this second example, the first inlet port 24c is connected to the source 19 of combustible fluid and the outlet port 24d is connected to the internal pipe 18, in particular to the inlet section 18a.

[0092] The first valve 24 makes it possible to cut off the flow of combustible fluid in the internal pipe 18. However, combustible fluid is already present in the internal pipe 18 before the first valve 24 is closed. This combustible fluid stored in the internal pipe 18 may ignite in the event of damage to the supply system 21. Advantageous embodiments of the invention will now be described to reduce this risk of ignition and further improve the safety system 21 of the invention.

[0093] According to an advantageous embodiment of the invention, the safety system 21 further comprises a fire-fighting device. The fire-fighting device can be arranged between the combustion chamber 8 and the external sheath 22. Thus, the combustible fluid remaining in the internal pipe 18 may ignite but the fire will be contained thanks to the fire-fighting device. The risks of ignition and explosion are reduced.

[0094] According to another embodiment of the invention illustrated in FIG. 6, the safety system 21 further comprises a second valve 24'.

[0095] The second 24' valve is hydraulic or pneumatic. The second 24' valve is pneumatically operated. The second 24' valve is normally closed.

[0096] The second valve 24' comprises a valve body 24a' delimiting an internal chamber 24b' for circulation of the combustible fluid. The second valve 24' further comprises an inlet port 24c' for the combustible fluid and an outlet port 24d' for the combustible fluid. The first inlet port 24c' and outlet port 24d' are provided in the valve body 24a' and open into the internal chamber 24b'. The first inlet port 24c' is connected to the internal passage 20 of the internal pipe 18. The outlet port 24d is connected to the internal passage 18 of the internal pipe 18 or to the combustion chamber 8, in particular to the injector. The second valve 24' further comprises a member movable between a first position and a second position.

[0097] The second valve 24' further comprises a control port 24e'. The control port 24e' is fluidically connected to the annular space 23. For example, a second hydraulic control line 25b connects the control port 24e' of the second valve 24' to the annular space 23. Thanks to such a fluid connection between the second valve 24' and the annular space 23, under the effect of the pressure variation in the annular space 23, the movable member is moved in the valve body 24a'. Thus, the movable member is moved from the first position to the second position when the pressure in the annular space 23 is lower than the threshold pressure.

[0098] The first position is an open position of the second valve 24'. The second valve 24' is maintained in the first position as long as the pressure in the annular space 23 is at least equal to the threshold pressure. In this position, the inlet port 24c' is in fluid communication with the outlet port 24d'. The combustible fluid is thus allowed to flow into the second valve 24' and the internal passage 20.

[0099] When the pressure in the annular space 23 drops and becomes lower than the threshold pressure, the movable member is moved into the second position. This is a position for closing the second valve 24' with respect to the circulation of the combustible fluid. In this second position, the fluid communication between the inlet port 24c' and the outlet port 24d' is closed. The combustible fluid cannot circulate in the second valve 24' and therefore the internal passage 20.

[0100] Preferably, the second valve 24' has a return spring 24f'. The movable member is returned to the second position by the return force of the return spring 24f'.

[0101] Preferably, the external sheath 22 is arranged between the first and second valves 24, 24'.

[0102] According to an exemplary embodiment illustrated in Figure 6, the second valve 24' is mounted around the internal pipe 18. According to this first example, the inlet port 24c' and outlet port 24d' are connected to the internal pipe 18, in particular to the outlet section 18c.

[0103] According to another exemplary embodiment, the second valve 24' is located between the internal pipe 18 and the combustion chamber 8.

[0104] The second valve 24' makes it possible to limit the circulation of the fluid remaining in the internal pipe 18. The second valve 24' therefore makes it possible to reduce the risk of ignition of the combustible fluid. Furthermore, the combustible fluid which may escape from the internal pipe 18 is expelled by the volume of inert gas in the internal space 23 released when the supply system 21 is damaged.

[0105] According to another embodiment illustrated in Figures 7 and 8, the first valve 24 further comprises a second inlet port 24g for an inert gas. According to this embodiment, in the second position of the movable member, the outlet port 24d communicates with the second inlet port 24g.

[0106] According to a first exemplary embodiment illustrated in FIG. 7, the second inlet port 24g is fluidically connected to the annular space 23. For example, a second hydraulic line 25a' connects the annular space 23 to the second inlet port 24g.

[0107] According to a second exemplary embodiment illustrated in FIG. 8, the second inlet range 24g is fluidically connected to a reservoir 26 of inert gas. The inert gas of the reservoir 26 is identical to or advantageously different from the inert gas of the annular space 23.

[0108] According to this embodiment, when the pressure in the annular space 23 drops and is lower than the threshold pressure, the movable member moves from the first position to the second position. In this second position, the second inert gas inlet port 24g is in fluid communication with the outlet port 24d. The inert gas then circulates in the internal passage 20 of the internal pipe 18. The inert gas makes it possible to expel the volume of combustible fluid stored in the internal pipe 18 before damage to the internal pipe 18. Such a configuration of the first valve 24 according to this embodiment therefore makes it possible to reduce the risk of ignition of the combustible fluid.

Claims

CLAIMS 1. System (17) for supplying combustible fluid to a combustion chamber (8) for a turbomachine (4) of an aircraft (1), the supply system (17) comprising: - an internal conduit (18) extending along an axis (C) and comprising an internal passage (20) for circulation of the combustible fluid, characterized in that the supply system (17) further comprises: - an external sheath (22) arranged coaxially around the internal pipe (18), - an annular space (23) delimited by the external sheath (22) around the internal pipe (18), the annular space (23) being intended to be subjected to a threshold pressure, and - a first valve (24) comprising: a first inlet port (24c) for the combustible fluid, an outlet port (24d) for the combustible fluid fluidically connected to the internal passage (20), a member movable between a first open position in which the first inlet port (24c) is in fluid communication with the outlet port (24d) and a second closed position preventing fluid communication between the inlet port (24c) and the outlet port (24d), and a control port (24e) fluidically connected to the annular space (23) so that the movable member is moved from the first position to the second position when the pressure in the annular space (23) is lower than the threshold pressure.

2. Supply system according to the preceding claim, characterized in that the internal pipe (18) comprises an inlet section (18a) for the combustible fluid, an outlet section (18b) for the combustible fluid, and a central section (18c) located along the axis (C) between the inlet and outlet sections (18a, 18b), the outer sheath (22) being arranged around the central section (18c) and the first valve (24) being arranged between the inlet section (18a) and the outer sheath (22).

3. A feed system according to any one of the preceding claims, characterized in that the annular space (23) is filled with an inert gas such as nitrogen (N2).

4. Supply system according to any one of the preceding claims, characterized in that the threshold pressure is between 1 bar and 120 bar.

5. Supply system according to any one of the preceding claims, characterized in that it comprises a second valve (24') comprising: an inlet port (24c') for the combustible fluid, an outlet port (24d') for the combustible fluid, a member movable between a first open position in which the inlet port (24c') is in fluid communication with the outlet port (24d') and a second closed position preventing fluid communication between the inlet port (24c') and the outlet port (24d'), and a control port (24e') fluidly connected to the annular space (23) so that the movable member is moved from the first position to the second position when the pressure in the annular space (23) is lower than the threshold pressure, the outer sheath (22) being located between the first and second valves (24, 24').

6. A supply system according to any one of claims 1 to 4, characterized in that the first valve (24) comprises a second port inlet (24g) of an inert gas, the outlet port (24d) being in fluid communication with the second inlet port (24g) in the second closed position of the first valve (24).

7. Feeding system according to the preceding claim, characterized in that the second inlet port (24g) is fluidically connected to the annular space (23).

8. A supply system according to claim 6, characterized in that the second inlet port (24g) is fluidically connected to a reservoir (26) of inert gas.

9. Turbomachine (4) for an aircraft (1), the turbomachine (4) extending around a longitudinal axis (X) and comprising from upstream to downstream: - a low pressure compressor (6), - a high pressure compressor (7), - a combustion chamber (8), - a high pressure turbine (9), and - a low pressure turbine (10), characterized in that the turbomachine (4) comprises a supply system (17) according to any one of the preceding claims connected to the combustion chamber (8).

10. Turbomachine according to the preceding claim, characterized in that the combustion chamber (8) comprises an annular enclosure (8a) and an injector (8b) opening into the annular enclosure (8a) and connected to the internal pipe (18).

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