Hydrogen propulsion unit comprising an inert gas injection device, aircraft comprising at least one such propulsion unit

Abstract

Hydrogen propulsion assembly comprising an inert gas injection device, aircraft comprising at least one such propulsion assembly The invention relates to a propulsion assembly comprising a fairing (34) delimiting an interior zone (ZI), a motorization (32) operating on hydrogen, a hydrogen conduit (38.1) connected to the motorization (32) and positioned in the interior zone (ZI), a debris ejection zone (36) as well as an inert gas container (46) positioned around or near the hydrogen conduit (38.1) and configured to perforate or break when it is impacted by debris coming from the motorization (32).Thus, in the event of a hydrogen leak due to the impact of debris, the inert gas leaving the inert gas container and injected into the inner zone makes it possible to obtain a dilution of the hydrogen in the inner zone and prevents the concentration of hydrogen and / or oxygen in the inner zone from reaching a critical threshold. The invention also relates to an aircraft comprising at least one such propulsion unit. Figure 4.

Description

Title of the invention: Hydrogen propulsion assembly comprising an inert gas injection device, aircraft comprising at least one such propulsion assembly

[0001] The present application relates to a hydrogen propulsion assembly comprising an inert gas injection device as well as to an aircraft comprising at least one such propulsion assembly.

[0002] According to an embodiment visible in [Fig.l], an aircraft propulsion assembly comprises a motorization 10 as well as a nacelle 12 in which the motorization 10 is positioned. The latter comprises a combustion chamber 10.1, a turbine 10.2 as well as an exhaust 10.3. The propulsion assembly comprises at least one hydrogen supply circuit 14 configured to convey hydrogen from a tank to the combustion chamber 10.1. The propulsion assembly may also comprise at least one hot air sampling circuit 16, 16' configured to capture hot air at the motorization 10, in order to preheat for example the air used in the air conditioning and defrosting systems of the aircraft, as well as an oil circuit 18 configured to cool the oil of the motorization 10.

[0003] The propulsion assembly comprises at least one debris ejection zone 20 which corresponds to a volume in which parts and / or debris, ejected from the engine 10 in the event of incidents, can impact the aircraft. These parts and / or debris, more or less significant, can come from different stages of the engine 10.

[0004] The hydrogen supply circuit 14 comprises at least one hydrogen conduit 22 passing through the debris ejection zone 20.

[0005] To limit the risks of hydrogen leakage, the hydrogen conduit 22 passing through the debris ejection zone 20 is a double-skin conduit.

[0006] To limit the risks of damage to the hydrogen conduit 22, the propulsion assembly comprises at least one shield 24 positioned between the motorization 10 and the hydrogen conduit 22. This shield 24 is sized to retain debris having energy levels below a given threshold. However, given the limits relating to its size and its mass, this shield 24 cannot retain debris having high energy levels. Consequently, such debris can impact the hydrogen conduit 22, which can generate a hydrogen leak inside the nacelle 12 and lead to an increase in the hydrogen concentration and the pressure in the nacelle 12.

[0007] The propulsion assembly may also comprise at least one system fire extinguishing system 26 to quickly extinguish a fire.

[0008] To limit the increase in pressure inside the nacelle 12, the propulsion assembly comprises at least one decompression door 26 configured to open automatically as soon as the pressure inside the nacelle 12 exceeds a trigger threshold and to connect the inside and the outside of the nacelle 12. The propulsion assembly may comprise two decompression doors 26, 26' making it possible to obtain ventilation inside the nacelle 12, which contributes to reducing the concentration of hydrogen inside the nacelle 12.

[0009] The ventilation of the interior of the nacelle is not optimal because its triggering is delayed in time and only occurs when the pressure inside the nacelle exceeds the triggering threshold.

[0010] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0011] To this end, the invention relates to a propulsion assembly comprising a fairing separating an interior zone and an exterior zone, a motorization positioned in the interior zone, a debris ejection zone positioned at least partially in the interior zone and into which debris originating from the motorization can be ejected, as well as a hydrogen supply system comprising at least one hydrogen conduit passing through the debris ejection zone.

[0012] According to the invention, the propulsion assembly comprises an inert gas injection device comprising an inert gas container which contains at least one inert gas under pressure, said inert gas container being positioned at least partly in the debris ejection zone, around or near the hydrogen conduit, and being configured to perforate or break when the inert gas container is impacted by debris coming from the motorization.

[0013] According to the invention, when debris ejected from the motor generates a leak at the hydrogen conduit, it also and simultaneously generates a leak at the inert gas container. The inert gas leaving the inert gas container and injected into the inner zone makes it possible to obtain a dilution of the hydrogen in the inner zone and prevents the concentration of hydrogen and / or oxygen in the inner zone from reaching a critical threshold.

[0014] According to another characteristic, the inert gas container has a resistance to perforation or rupture lower than that of the hydrogen conduit.

[0015] According to another characteristic, the inert gas contained in the inert gas container has a temperature lower than 20°C.

[0016] According to another characteristic, the inert gas container comprises at least one inert gas conduit which has a section juxtaposed with the hydrogen conduit.

[0017] According to another characteristic, the section of the inert gas conduit is positioned between the engine and the hydrogen pipe.

[0018] According to another characteristic, the inert gas container comprises at least one inert gas conduit which has a section in which the hydrogen conduit is inserted at least in part.

[0019] According to another characteristic, the propulsion assembly comprises at least one shield positioned between, on the one hand, the motorization and, on the other hand, the hydrogen conduit and the section of the inert gas conduit.

[0020] According to another characteristic, the hydrogen supply system comprises a cut-off valve configured to occupy passing and blocked states, the propulsion assembly comprising a control for monitoring the state of the cut-off valve as well as at least one first leak detection system configured to inform the control in order to monitor the state of the cut-off valve.

[0021] According to another characteristic, the first leak detection system comprises at least one element chosen from at least one pressure sensor configured to measure the pressure in the interior zone, at least one pressure sensor configured to measure the pressure of the inert gas in the inert gas container and at least one wire cut detector positioned along the hydrogen conduit.

[0022] According to another characteristic, the first wire cut detector comprises a wire running along the hydrogen conduit, the propulsion assembly comprising a shield positioned between the motorization and the wire of the first wire cut detector.

[0023] According to another characteristic, the inert gas container comprises a trigger valve configured to occupy a first state in which the trigger valve authorizes an injection of inert gas into the interior zone and a second state in which the trigger valve prevents any flow of inert gas into the interior zone. In addition, the inert gas injection device comprises a control for monitoring the state of the trigger valve as well as a second leak detection system configured to detect a leak at the motorization and inform the control of the trigger valve in order to monitor its state.

[0024] According to another characteristic, the propulsion assembly comprises a shield. In addition, the second leak detection system comprises at least one second wire cut detector comprising at least one wire positioned between the motorization and the shield.

[0025] The invention also relates to an aircraft comprising at least one propulsion assembly according to one of the preceding characteristics.

[0026] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the drawings. annexed among which:

[0027] [Fig.l] is a schematic longitudinal section of a propulsion assembly illustrating an embodiment of the prior art,

[0028] [Fig.2] is a schematic longitudinal section of a propulsion assembly illustrating an embodiment of the invention,

[0029] [Fig.3] is a schematic longitudinal section of a propulsion assembly illustrating another embodiment of the invention,

[0030] [Fig.4] is a schematic longitudinal section of a propulsion assembly illustrating another embodiment of the invention.

[0031] According to one configuration, an aircraft comprises at least one propulsion assembly 30 operating on hydrogen.

[0032] According to embodiments visible in Figures 2 to 4, a propulsion assembly 30 comprises a motorization 32 operating on hydrogen as well as a nacelle 34 in which the motorization 32 is positioned.

[0033] According to one configuration, the engine 32 comprises a combustion chamber 32.1, a turbine 32.2, an exhaust 32.3 as well as a casing 32.4 forming an envelope in which the majority of the elements of the engine 32 are positioned. The nacelle 34 comprises a fairing 34.1 separating an interior zone ZI in which the engine 32 is positioned and an exterior zone ZE.

[0034] The propulsion assembly 30 comprises at least one debris ejection zone 36, positioned at least partially in the interior zone ZI, into which debris from the engine 32 can be ejected in the event of incidents. According to one arrangement, this debris ejection zone 36 is positioned around the turbine 32.2. It extends between a front boundary 36.1 and a rear boundary 36.2, the concepts front and rear referring to the direction of flow of the gases in the engine 32. Of course, the invention is not limited to this arrangement for the debris ejection zone 36.

[0035] The propulsion assembly 30 comprises at least one hydrogen supply system 38 configured to convey hydrogen from at least one tank to the engine 32. This hydrogen supply system 38 comprises at least one hydrogen conduit 38.1, in which hydrogen circulates, passing through the debris ejection zone 36. According to one configuration, the hydrogen conduit 38.1 is a double-skinned conduit. According to one arrangement, the hydrogen conduit 38.1 passes through the front and rear boundaries 36.1, 36.2 of the debris ejection zone 36.

[0036] The motorization 32, the nacelle 34 and the hydrogen supply system 38 are not described further because they may be identical to those of the prior art.

[0037] According to an embodiment visible in [Fig.4], to limit the risks of damage to the hydrogen conduit 38.1, the propulsion assembly 30 comprises at least one shield 40 positioned between the motorization 32 and the hydrogen conduit 38.1 and configured to retain at least one piece of debris having an energy level below a given threshold. This shield 40 is not described further because it may be identical to those of the prior art.

[0038] According to an embodiment visible in [Fig.4], the propulsion assembly 30 comprises at least one fire extinguishing system 42. This fire extinguishing system 42 is not described further because it may be identical to those of the prior art.

[0039] According to a configuration visible in [Fig.4], the propulsion assembly 30 comprises at least one decompression door 44 configured to open automatically as soon as the pressure in the inner zone ZI of the nacelle 34 exceeds a trigger threshold and to connect the inner zone ZI and the outer zone ZE of the nacelle. In the event of rupture or perforation of the hydrogen conduit 38.1, each decompression door 44 makes it possible to prevent the pressure in the inner zone ZI of the nacelle 34 from exceeding a given threshold, thus limiting the risks of overpressure and bursting of the nacelle 34.

[0040] According to one arrangement, the propulsion assembly 30 comprises at least first and second decompression doors 44, 44' positioned on either side of the debris ejection zone 36. Thus, the first decompression door 44 is positioned in front of the debris ejection zone 36 and the second decompression door 44' is positioned at the rear of the debris ejection zone 36. This arrangement promotes the ventilation of the interior zone ZI, in particular the part of the interior zone ZI in which the debris ejection zone 36 is located. As soon as they are opened, the first and second decompression doors 44, 44' make it possible to limit the pressure and the hydrogen concentration in the interior zone ZI.

[0041] The propulsion assembly 30 comprises an inert gas injection device 45 which comprises an inert gas container 46 which contains at least one inert gas, positioned at least partly in the debris ejection zone 36 and in proximity to the hydrogen conduit 38.1, the inert gas container 46 being configured to perforate or break when it is impacted by debris coming from the motorization 32. According to one configuration, the inert gas container 46 has a resistance to perforation or rupture lower than that of the hydrogen conduit 38.1.

[0042] Therefore, when debris generates a leak at the hydrogen conduit 38.1, it also and simultaneously generates a leak at the inert gas container 46 positioned next to the hydrogen conduit 38.1. The hydrogen and the inert gas contained respectively in the hydrogen conduit 38.1 and the inert gas container 46 then propagate into the inner zone ZI. The inert gas leaving the inert gas container 46 and injected into the inner zone ZI makes it possible to obtain a dilution of the hydrogen in the inner zone ZI and prevents the hydrogen concentration in the inner zone ZI does not reach a critical threshold.

[0043] The inert gas container 46 contains at least one inert gas under pressure. For the remainder of the description, the term “one or the inert gas” means a single inert gas or a mixture of inert gases.

[0044] The inert gas may be nitrogen or helium. Of course, the invention is not limited to these gases for the inert gas.

[0045] The inert gas contained in the inert gas container 46 has a temperature below 20°C.

[0046] According to embodiments visible in Figures 2 and 4, the inert gas container 46 comprises at least one inert gas conduit 48 which has a section 48.1 juxtaposed with the hydrogen conduit 38.1. According to one arrangement, the section 48.1 of the inert gas conduit 48 is positioned between the motorization 32 and the hydrogen conduit 38.1. In the presence of a shield 40, the section 48.1 of the inert gas conduit 48 is positioned between the shield 40 and the hydrogen conduit 38.1. According to one arrangement, the section 48.1 of the inert gas conduit 48 extends approximately from the front boundary 36.1 to the rear boundary 36.2 of the debris ejection zone 36 and is positioned in the same angular sector as the hydrogen conduit 38.1.

[0047] According to another embodiment visible in [Fig. 3], the inert gas conduit 48 has a section 48.2 positioned around the hydrogen conduit 38.1 which is consequently inserted at least partly into the section 48.2. According to this embodiment, the annular section 48.2 and the hydrogen conduit 38.1 are substantially coaxial. In operation, the debris impacts the annular section 48.2 before impacting the hydrogen conduit 38.1.

[0048] According to a configuration visible in [Fig.4], the inert gas container 46 comprises at least one reservoir 50 of pressurized inert gas connected to the inert gas conduit 48. This configuration makes it possible to inject a large volume of inert gas in the event of a leak.

[0049] According to embodiments visible in Figures 3 and 4, the hydrogen supply system 38 comprises a cut-off valve 52, called the FSOV valve (for Fuel Shut-off Valve in English), configured to occupy a passing state in which the cut-off valve 52 allows a flow of hydrogen towards the motorization 32 as well as a blocked state in which the cut-off valve 52 prevents any flow of hydrogen towards the motorization 32. This cut-off valve 52 is positioned in the outer zone ZE of the nacelle 34 (outside the nacelle 34) to block any flow of hydrogen towards the inner zone ZI in the blocked state.In addition, the propulsion assembly 30 comprises a control 54 configured to control the state of the cut-off valve 52 as well as at least one first leak detection system 56 comprising at least one element chosen from at least one pressure sensor configured to measure the pressure in the zone in. interior ZI and positioned near the hydrogen conduit 38.1, at least one pressure sensor 58 configured to measure the pressure of the inert gas in the inert gas container 46 and at least one wire cut detector 60, the first leak detection system 56 being configured to detect a hydrogen leak and inform the control 54 in order to control the state of the cut-off valve 52.

[0050] According to an embodiment visible in [Fig. 3], the first leak detection system 56 comprises a first wire cut detector 60 which comprises a wire positioned along the hydrogen conduit 38.1. The wire of the first wire cut detector 60 extends at least from the front boundary 36.1 to the rear boundary 36.2 of the debris ejection zone 36.

[0051] According to another embodiment visible in [Fig.4], the first leak detection system 56 comprises a first wire cut detector 60 which comprises a wire positioned along the hydrogen conduit 38.1 as well as a pressure sensor 58 configured to measure the pressure of the inert gas in the tank 50 of the inert gas container 46.

[0052] According to these two embodiments, the wire of the first wire cut detector 60, running along the hydrogen conduit 38.1, is further away from the motorization 32 than the shield 40. Thus, the latter is positioned between the motorization 32 and the wire of the first wire cut detector 60.

[0053] Of course, the invention is not limited to these embodiments for the first leak detection system. Thus, other sensors or other combinations of sensors are conceivable.

[0054] According to an embodiment visible in [Fig. 4], the inert gas container 46 comprises at least one exhaust 46.1 as well as a trigger valve 46.2 configured to occupy a first state in which the trigger valve 46.2 authorizes the injection of inert gas via the exhaust 46.1 into the interior zone ZI and a second state in which the trigger valve 46.2 prevents any flow of inert gas into the interior zone ZI via the exhaust 46.1. In addition, the inert gas injection device 45 comprises a control for monitoring the state of the trigger valve 46.2 as well as a second leak detection system 62 configured to detect a leak at the casing 32.4 of the motorization 32 and inform the control of the trigger valve 46.2 in order to monitor its state.

[0055] According to one configuration, the second leak detection system 62 comprises at least one second wire cut detector 64 which comprises at least one wire positioned in the debris ejection zone 36. According to one arrangement, the wire of the second wire cut detector 64 extends at least from the front boundary 36.1 to the rear boundary 36.2 of the debris ejection zone 36. According to one embodiment, the wire of the second wire cut detector 64 is positioned between the motorization 32 and the shield 40.

[0056] Thus, according to the embodiment visible in [Fig.4], the propulsion assembly 30 comprises a first wire cut detector 60 for monitoring the state of the cut-off valve 52 of the hydrogen supply system 38 as well as a second wire cut detector 64 for monitoring the state of the trigger valve 46.2 of the inert gas injection device 45.

[0057] In operation, when debris with low energy levels pierces the casing 32.4 of the motor 32, they are retained by the shield 40 and do not pierce the hydrogen conduit 38.1. However, hot gases can escape from the motor 32. The debris ejected from the motor 32 having pierced its casing 32.4 cuts the wire of the second wire cut detector 64, causing the opening of the trigger valve 46.2 and the injection of cold inert gas into the interior zone ZI, thus limiting the increase in temperature of the gas mixture in this interior zone ZI.

[0058] If debris with high energy levels is ejected from the motor 32, it may pass through the shield 40, impact the hydrogen conduit 38.1 and possibly perforate the fairing 34.1 of the nacelle 34.

[0059] Whatever the flight phase, the flow rate of hydrogen in the hydrogen conduit 38.1 is such that it theoretically leads to rapid filling of the inner zone ZI in the event of a leak at the hydrogen conduit 38.1. Given its position close to the hydrogen conduit 38.1, the inert gas container 46 is perforated or broken simultaneously with the hydrogen conduit 38.1, which leads to the injection of an inert gas into the inner zone ZI.

[0060] The injection of cold inert gas leads to limiting the increase in the temperature of the gas mixture present in the inner zone ZI and the hydrogen concentration in the inner zone ZI, which does not reach a critical concentration. Thanks to this injection of inert gas, the inner zone ZI is saturated with inert gas and contains a gaseous medium rich in hydrogen and inert gas having a small quantity of oxygen, which greatly limits the risks of explosion.

[0061] The injection of inert gas into the interior zone ZI simultaneously with that of hydrogen leads to a more rapid increase in the pressure in the interior zone ZI and therefore to a more rapid opening of the decompression door(s) 44, 44', leading to ventilation of said interior zone ZI.

[0062] In addition to the rupture of the hydrogen conduit 38.1 and the inert gas conduit 48, the debris ejected by the motor 32 cuts the wire of the first wire cut detector 60, which causes the closure of the cut-off valve 52. In parallel, the pressure sensor 58 detects the drop in pressure of the inert gas and also causes closing the cut-off valve 52. This redundancy increases safety.

Claims

Claims

1. A propulsion assembly comprising a fairing (34.1) separating an inner zone (ZI) and an outer zone (ZE), a motorization (32) positioned in the inner zone (ZI), a debris ejection zone (36) positioned at least partially in the inner zone (ZI) and into which debris from the motorization (32) can be ejected, and a hydrogen supply system (38) comprising at least one hydrogen conduit (38.1) which passes through the debris ejection zone (36); characterized in that the propulsion assembly comprises an inert gas injection device (45) comprising an inert gas container (46) which contains at least one inert gas under pressure, said inert gas container (46) being positioned at least partially in the debris ejection zone (36), around or near the hydrogen conduit (38.1), and being configured to puncture or rupture when the inert gas container (46) is impacted by debris from the motorization (32).

2. Propulsion assembly according to the preceding claim, characterized in that the inert gas container (46) has a resistance to perforation or rupture lower than that of the hydrogen conduit (38.1).

3. Propulsion assembly according to one of the preceding claims, characterized in that the inert gas contained in the inert gas container (46) has a temperature of less than 20°C.

4. Propulsion assembly according to one of the preceding claims, characterized in that the inert gas container (46) comprises at least one inert gas conduit (48) which has a section (48.1) juxtaposed with the hydrogen conduit (38.1).

5. Propulsion assembly according to the preceding claim, characterized in that the section (48.1) of the inert gas conduit (48) is positioned between the motorization (32) and the hydrogen conduit (38.1).

6. Propulsion assembly according to one of claims 1 to 3, characterized in that the inert gas container (46) comprises at least one inert gas conduit (48) which has a section (48.2) in which the hydrogen conduit (38.1) is inserted at least in part.

7. Propulsion assembly according to one of claims 4 to 6, characterized in that the propulsion assembly comprises at least one shield (40) positioned between on the one hand the motorization (32) and on the other hand the conduit hydrogen (38.1) and the section (48.1) of the inert gas conduit (48).

8. Propulsion assembly according to one of the preceding claims, characterized in that the hydrogen supply system (38) comprises a cut-off valve (52) configured to occupy passing and blocked states and in that the propulsion assembly (30) comprises a control (54) for monitoring the state of the cut-off valve (52) as well as at least one first leak detection system (56) configured to detect a hydrogen leak and inform the control (54) in order to monitor the state of the cut-off valve (52).

9. Propulsion assembly according to the preceding claim, characterized in that the first leak detection system (56) comprises at least one element chosen from at least one pressure sensor configured to measure the pressure in the interior zone (ZI), at least one pressure sensor configured to measure the pressure of the inert gas in the inert gas container (46) and at least one wire cut detector (64) positioned along the hydrogen conduit (38.1).

10. Propulsion assembly according to the preceding claim, characterized in that the first wire cut detector (60) comprises a wire running along the hydrogen conduit (38.1) and in that the propulsion assembly comprises a shield (40) positioned between the motorization (32) and the wire of the first wire cut detector (60).

11. Propulsion assembly according to one of the preceding claims, characterized in that the inert gas container (46) comprises a trigger valve (46.2) configured to occupy a first state in which the trigger valve (46.2) authorizes an injection of inert gas into the interior zone (ZI) and a second state in which the trigger valve (46.2) prevents any flow of inert gas into the interior zone (ZI) and in that the inert gas injection device (45) comprises a control for monitoring the state of the trigger valve (46.2) as well as a second leak detection system (62) configured to detect a leak at the motorization (32) and inform the control of the trigger valve (46.2) in order to monitor its state.

12. Propulsion assembly according to the preceding claim, characterized in that the propulsion assembly comprises a shield (40) and in that the second leak detection system (62) comprises at least one second wire cut detector (64) comprising at least one wire positioned between the motorization (32) and the shield (40).

13. Aircraft comprising at least one propulsion assembly according to one of the preceding claims.

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