AIRCRAFT PROPULSION UNIT

Abstract

PROPULSION ASSEMBLY FOR AIRCRAFT The invention relates to a propulsion assembly (151) comprising a combustion chamber (158) and a turbine (160), a nacelle (149) with a front cowl (147b) facing the turbine (160) and pierced with a window (147a) and a rear cowl (147d) at the rear of the turbine (160), a fire barrier (192) between the front cowl (147b) and the rear cowl (147d), a dihydrogen supply pipe (170) winding from the inside of the rear cowl (147d), then in a sealed manner through the fire barrier (192), then through said window (147a) to the combustion chamber (158), where the supply pipe (170) comprises an intermediate section (182) between the fire barrier (192) and the window (147a), and a plate (183) tightly fixed to the intermediate section (182) and tightly fixed to the front cover (147b) around said window (147a).With such an arrangement, the sealing on both sides of the nacelle covers is guaranteed. Fig. 2.

Description

Title of the invention: PROPULSION ASSEMBLY FOR AIRCRAFT Technical field

[0001] The present invention relates to a propulsion unit for an aircraft, said propulsion unit comprising a nacelle, a motorization system such as a turboprop housed in the nacelle and a set of pipes arranged to supply the motorization system with dihydrogen from a dihydrogen tank. The invention also relates to an aircraft comprising at least one such propulsion unit. STATE OF THE PRIOR ART

[0002] In order to move, an aircraft conventionally comprises at least one propulsion unit comprising a powertrain system such as a turboprop. Such a powertrain system comprises a core which is enclosed in a casing and which comprises, among other things, from upstream to downstream, a compressor, a combustion chamber and a turbine. The casing is housed in a nacelle. The powertrain system also comprises a propeller driven in rotation by the core. The compressor and the turbine each have blades which are fixed to a rotating shaft.

[0003] The propulsion unit also comprises a chassis which is fixed to a structure of the wing of the aircraft and thus constitutes a mounting mast under the wing.

[0004] To limit pollution due to the use of kerosene, it is envisaged to use dihydrogen as fuel in the combustion chamber.

[0005] This dihydrogen is brought from a tank to the combustion chamber by a dihydrogen pipe which extends at least partly into the propulsion unit. Due to the structure of the propulsion unit and its position under the wing and on the front of the wing, the dihydrogen pipe passes through the chassis coming from the wing and thus runs from the rear to the front to the combustion chamber.

[0006] In the solution envisaged, the dihydrogen pipe runs outside the casing to reach the combustion chamber through the casing.

[0007] In the event of an incident on the motorization system, in particular in the event of an uncontained engine failure (also called UERF for "Uncontained Engine Rotor Failure" in English), it may happen that certain blades of the turbine or the compressor become detached from the shaft and, due to their speed, they pass through the casing with the risk of cutting the hydrogen pipe. In such a situation, in order to limit a risk of fire or explosion, it is advisable that hydrogen from the pipe does not risk accumulating inside the nacelle. Statement of the invention

[0008] An object of the present invention is to propose a propulsion assembly which comprises a dihydrogen supply pipe of which an intermediate section is arranged around the turbine which winds around the nacelle where the intermediate section has a particular architecture making it possible to ensure sealing against dihydrogen between the interior and the exterior of the nacelle.

[0009] For this purpose, a propulsion unit for an aircraft is proposed comprising:

[0010] - a motorization system comprising a core enclosed in a casing and having a combustion chamber and a turbine equipped with blades rotating around a longitudinal axis,

[0011] - a nacelle in which the motorization system is housed, and comprising covers including a front cover extending opposite and in front of the turbine and pierced with a window arranged at the front of the turbine and a rear cover extending at the rear of the turbine,

[0012] - a fire barrier which extends between the front hood and the rear hood,

[0013] - a supply pipe intended to convey dihydrogen, winding through the inside of the rear cowl to the rear of the turbine, then in a sealed manner through the fire barrier to reach the outside of the front cowl, then through said window to the combustion chamber, where the supply pipe consists of several sections fixed to each other and where an intermediate section extends from downstream of the fire barrier to downstream of the window, and

[0014] - a plate fixed in a sealed manner to the intermediate section and fixed to the cover before, so as to make the said window watertight.

[0015] With such an arrangement, the intermediate section is outside the nacelle and, if it is impacted by a blade burst, the dihydrogen from the leak spreads outside the nacelle and is discharged to the outside. Furthermore, in the event of a leak from the intermediate section outside the nacelle, the sealed assembly proposed here ensures that the dihydrogen does not spread inside the nacelle.

[0016] Advantageously, the fire barrier extends transversely relative to the longitudinal axis of the motorization system.

[0017] Advantageously, the fire barrier extends inside the front cover and separates the nacelle into a front zone and a rear zone which are sealed from each other.

[0018] Advantageously, the propulsion assembly comprises an outer cowl fixed to the outside of the front cowl of the nacelle, encompassing the part of the supply pipe which is between the fire barrier and the window, and the propulsion assembly has an air inlet at the front of the outer cowl, between the latter and the front cowl of the nacelle and an outlet at the rear of the outer cowl, between the latter and the cowls of the nacelle.

[0019] Advantageously, the exit is at the front relative to said fire barrier.

[0020] Advantageously, the outlet is located at an upper part of the outer cover.

[0021] Advantageously, the propulsion assembly comprises a sealed flange comprising a shoe secured to the fire barrier and having a first seat forming a half-cylinder and an extension having a second seat forming a half-cylinder, securing means which ensure the fixing of the extension to the shoe so that the seats are joined to each other to form a cylinder, and a cylindrical seal housed in said cylinder and through which the supply pipe passes.

[0022] Advantageously, the propulsion unit comprises a hatch mounted in a removable manner on a hood.

[0023] The invention also proposes an aircraft comprising a dihydrogen tank and at least one propulsion unit according to one of the preceding variants, where the supply pipe is fluidically connected to the dihydrogen tank. Brief description of the drawings

[0024] The above-mentioned features of the invention, as well as others, will appear more clearly on reading the following description of an exemplary embodiment, said description being made in relation to the attached drawings, among which:

[0025] [Fig-1] is a side view of an aircraft comprising a propulsion unit according to the invention,

[0026] [Fig.2] is a schematic representation in top view of the propulsion assembly according to the invention, and

[0027] [Fig.3] is a perspective view of a flange implemented in the propulsion assembly according to the invention.

[0028] DETAILED DESCRIPTION OF EMBODIMENTS

[0029] In the following description, the terms relating to a position are taken with reference to an aircraft in a forward position, that is to say as shown in [Fig.l] where the arrow F shows the direction of forward movement of the aircraft.

[0030] In the following description, and by convention, X is the longitudinal axis of the motorization system which is parallel to the longitudinal axis of the aircraft oriented positively forward in the direction of advancement of the aircraft, Y is the transverse axis which is horizontal when the aircraft is on the ground, and Z is the vertical axis or vertical height when the aircraft is on the ground, these three axes X, Y and Z being orthogonal to each other.

[0031] [Fig.l] shows an aircraft 100 which has a fuselage 102 on either side of which a wing 104 is fixed. Under each wing 104 is fixed at least one assembly propulsion unit 151 according to the invention which comprises a nacelle 149 made up of covers 147 forming an aerodynamic exterior surface.

[0032] [Fig. 2] shows the propulsion assembly 151 which also comprises a motorization system 150 which is shown schematically. The propulsion assembly 151 comprises a frame 180 which ensures the attachment of the propulsion assembly 151 to a structure of the wing 104 and constitutes a suspension mast. The frame 180 is attached to the structure of the wing by attachment means known to those skilled in the art. The frame 180 and the motorization system 150 are housed inside the nacelle 149.

[0033] In the embodiment of the invention shown in [Fig. 2], the motorization system 150 is a turboprop engine which comprises a core 152 which is enclosed in a casing 154. In the embodiment of the invention shown in [Fig. 2], the casing 154 is housed inside the nacelle 149 and is fixed there by any suitable means known to those skilled in the art.

[0034] Outside air enters the nacelle 149 through an opening provided in the covers 147 at the front of the nacelle 149 which is also fixed to the chassis 180 by suitable fixing means known to those skilled in the art.

[0035] Inside the nacelle 149, the primary air flow 10 enters the core 152 to supply a combustion chamber 158 of the motorization system 150 with oxygen.

[0036] The casing 154 is thus open at the front to allow the introduction of the primary flow 10 into the core 152 and open at the rear to allow the exhaust of the gases resulting from the combustion through a nozzle. The core 152 comprises, from upstream to downstream, a compressor 156, the combustion chamber 158 and a turbine 160. The compressor 156 and the turbine 160 are provided with blades 161 rotating around the longitudinal axis X.

[0037] The primary flow 10 thus passes successively through the compressor 156 where it is compressed before being injected into the combustion chamber 158 where it is mixed with the fuel. The gases resulting from the combustion then pass through the turbine 160 and drive it in rotation. The turbine 160 then in turn drives the compressor 156 in rotation and the gases are then ejected to the rear.

[0038] In the case of a turboprop, the engine system 150 comprises a propeller 162 which is at the front and driven in rotation by the turbine 160, possibly through a gearbox. The propeller 162 rotates around an axis of rotation parallel to the longitudinal axis X and possibly offset relative to it.

[0039] The propulsion assembly 151 also comprises a supply pipe 170 fluidically connected to a dihydrogen tank 172 of the aircraft 100 to convey the dihydrogen to the combustion chamber 158. The supply pipe 170 thus winds inside the nacelle 149, from the rear of the nacelle 149 outside the casing 154 to the rear of the turbine 160.

[0040] The propulsion assembly 151 also comprises an injector ramp 184 which is fluidically connected to the supply pipe 170 and which is housed in the nacelle 149. The injector ramp 184 is arranged here around the casing 154 and the combustion chamber 158. The injector ramp 184 is equipped with injectors 185 which plunge into the combustion chamber 158 in front of the turbine 160, here through the casing 154.

[0041] The nacelle 149 has a front cover 147b which extends on the side opposite and in front of the turbine 160. The front cover 147b is pierced with a window 147a arranged in front of the turbine 160.

[0042] The nacelle 149 also has a rear cover 147d which extends to the rear of the turbine 160.

[0043] In the embodiment of the invention shown in [Fig.2], the front cover 147b is closer to the casing 154 than is the rear cover 147d which is therefore located outside relative to the front cover 147b.

[0044] The propulsion unit 151 also comprises a fire barrier 192 made of a high-temperature resistant material. The fire barrier 192 extends between the front cover 147b and the rear cover 147d and thus ensures the junction between them. The fire barrier 192 therefore separates the space into a rear zone 192b which is at the rear of the fire barrier 192 and inside the rear cover 147d and into a lateral zone 192c which is at the front of the fire barrier 192 and outside the front cover 147b.

[0045] The space also has a front area 192a which is forward of the fire barrier 192 and inside the front cover 147b.

[0046] The supply pipe 170 is housed in the rear zone 192b, i.e. inside the rear cover 147d up to the rear of the turbine 160. The supply pipe 170 then passes in a sealed manner through the fire barrier 192 to wind through the lateral zone 192c, i.e. outside the front cover 147b, and finally passes through the window 147a to reach the combustion chamber 158 through the injector ramp 184 and the injectors 185.

[0047] The supply pipe 170 is made up of several sections 182 which are fixed in the extension of one another and an intermediate section 182 extends from downstream of the fire barrier 192 to downstream of the window 147a relative to the direction of flow of the dihydrogen in the supply pipe 170.

[0048] The intermediate section 182 thus comprises a first end 182a which is fluidically connected to the part of the supply pipe 170 coming from the tank 172 and a second end 182b which is fluidically connected to the part of the supply pipe 170 joining the combustion chamber 158. In order to ensure the attachment of each end 182a-b to the part of the pipe corresponding supply 170, each end and each part has a fixing flange intended to be secured to the fixing flange of the associated element.

[0049] Due to the construction of the propulsion assembly 151, the first end 182a is thus outside the nacelle 149, and more particularly the front cover 147b, and the second end 182b is thus inside the nacelle 149, and more particularly the front cover 147b.

[0050] The dimensions of the window 147a are sufficient to allow said second end 182b to pass through. The connection of the second end 182b to the corresponding part of the supply pipe 170 is therefore made through the window 147a.

[0051] The propulsion assembly 151 also comprises a plate 183 which is fixed to the intermediate section 182 by forming a collar around said intermediate section 182. The fixing is here sealed to prevent the passage of dihydrogen between the plate 183 and the intermediate section 182 as explained below. The fixing is carried out for example by welding.

[0052] The plate 183 is furthermore fixed in a sealed manner to the front cover 147b by closing the window 147a so as to also make it sealed. The plate 183 is thus fixed around the window 147a. The fixing of the plate 183 to the front cover 147b is preferably removable, for example using screw elements, to ensure the disassembly of the intermediate section 182 if necessary.

[0053] With such an arrangement, if a blade debris 161 passes through the casing 154 and the cowls 147, damaging the supply pipe 170 in the lateral zone 192c, the dihydrogen escaping from the latter is evacuated to the outside. If a leak appears at the part of the supply pipe 170 which is outside the nacelle 149, the sealing of the attachment of the supply pipe 170 to the plate 183 and the sealing of the attachment of the plate 183 to the front cowl 147b prevents the flow of dihydrogen towards the inside of the nacelle 149. In the same way, the sealed crossing of the supply pipe 170 through the fire barrier 192 prevents the flow of dihydrogen towards the lateral zone 192c.Since the window 147a is located at the front of the turbine 160 and the fire barrier 192 is located at the rear of the turbine 160, the portion of the feed pipe 170, and therefore of the intermediate section 182, running opposite the turbine 160 is located outside the front cover 147b and therefore outside the nacelle 149. Consequently, in the event of debris being projected from the turbine 160, the debris can only reach the feed pipe 170 and the intermediate section 182 in said portion located outside the nacelle 149 and in the lateral zone 192c. Since there is no feed pipe inside the nacelle 149 on the sides of the turbine 160, it is not likely to be impacted by debris, which makes it possible to avoid a leak. of hydrogen inside the nacelle 149. This protects the nacelle 149 against the risk of fire or explosion.

[0054] In the embodiment of the invention presented in [Fig.2], the fire barrier 192 extends transversely relative to the longitudinal axis X and here the fire barrier 192 extends inside the front cover 147b and separates the nacelle 149 into the front zone 192a and the rear zone 192b which are then sealed relative to each other.

[0055] The fire barrier 192 here extends around the casing 154.

[0056] Thus, any fire that starts in either of the zones 192a-c remains confined in this area without spreading to the neighboring area. In particular, a fire starting in the front area 192a containing the combustion chamber 158 cannot spread into one of the areas 192b or 192c in which the hydrogen supply pipe 170, 182 runs.

[0057] In the embodiment of the invention shown in [Fig.2], the intermediate section 182 extends along the turbine 160 between the rear of the turbine 160 and the front of the turbine 160 and for at least a portion outside the front cover 147b of the nacelle 149.

[0058] At the crossing of the fire barrier 192 and the front cover 147b, the supply pipe 170 is generally perpendicular respectively to the fire barrier 192 and to the front cover 147b in order to facilitate the installation of the seal.

[0059] According to a particular embodiment, the intermediate section 182 is arranged in the upper part of the nacelle 149 and above the motorization system 150 for better evacuation of the dihydrogen in the event of a leak.

[0060] In the embodiment of the invention presented in [Fig. 2], the plate 183 is fixed against the outer face of the front cover 147b, that is to say the face facing the outside of the nacelle 149. The dimensions of the plate 183 are therefore here such that the plate 183 cannot pass through the window 147a.

[0061] The plate 183 can take any conceivable shape depending on the shape of the window 147a. It can thus be circular, rectangular, etc.

[0062] In a particular embodiment, the supply pipe 170 and the injection ramp 184 are double-skin pipes to secure the flow of dihydrogen and the fixing flanges between each of them are adapted to such double-skin pipes.

[0063] To seal the attachment between the plate 183 and the front cover 147b, seals 147c, in particular seals resistant to high temperatures, are placed between the plate 183 and the front cover 147b.

[0064] In the embodiment shown in [Fig.2], to improve the aerodynamics of the propulsion unit 151, the latter comprises an outer cover 206 fixed to the outside of the covers 147 of the nacelle 149 and more particularly of the front cover 147b, encompassing the part of the supply pipe 170 which is between the fire barrier 192 and the window 147a, that is to say at least in part the intermediate section 182. The outer cover 206 thus extends the rear cover 147d forward.

[0065] The propulsion unit 151 then has an air inlet 208 at the front of the outer cowl 206, between the latter and the front cowl 147b of the nacelle 149 and an outlet 210 at the rear of the outer cowl 206, between the latter and the cowls 147 of the nacelle 149. Thus, the outside air which enters through the air inlet 208 will carry any di-hydrogen towards the air outlet 210 in the event of a leak.

[0066] To prevent dihydrogen from spreading into the rear zone 192b in the event of a leak in the lateral zone 192c, the outlet 210 is at the front relative to the fire barrier 192.

[0067] According to a particular embodiment, the outlet 210 is located at an upper part of the outer cover 206 for better evacuation of the dihydrogen in the event of a leak.

[0068] [Fig. 3] shows an example of a watertight flange 300 implemented to ensure the passage of the supply pipe 170 through the fire barrier 192.

[0069] The watertight flange 300 comprises a shoe 302 which is secured to the fire barrier 192, for example by welding, which has a first seat 302a which forms a half-cylinder.

[0070] The sealed flange 300 also comprises an extension 304 which has a second seat 304a also forming a half-cylinder. The extension 304 comes to bear in a sealed manner against the outer cover 206.

[0071] In the assembled position, the two half-cylinders are joined to each other so as to form a cylinder.

[0072] The watertight flange 300 also includes securing means, such as screws, which ensure the fixing of the extension 304 to the shoe 302 in the assembled position.

[0073] The sealed flange 300 also comprises a seal 306 which is also cylindrical in shape and which is housed in the cylinder formed by the shoe 302 and the extension 304. The seal 306 also has a central bore 308 through which the supply pipe 170 passes in a sealed manner.

[0074] In the embodiment of the invention presented in [Fig. 3], the seal 306 is made up of two half-cylinder elements which facilitates installation around the supply pipe 170. These elements are chosen so as to be fire resistant.

[0075] For maintenance reasons, for example to replace the intermediate section 182, it is necessary to access the second end 182b to separate it from the part of the supply pipe 170 which is downstream. For this to do, according to a particular embodiment of the invention, one of the covers 147 is equipped with a hatch which is removably mounted on said cover 147.

[0076] The hatch may be hingedly mounted between an open position and a closed position. The hatch is positioned such that a technician has access to the second end 182b when the hatch is in the open position.

[0077] Conventionally, according to a particular embodiment, the hatch is equipped with hinges and a lock which allows the hatch to be articulated on the cover 147 and the said hatch to be locked with the said cover 147 in the closed position.

[0078] Alternatively, the hatch is a removable hatch secured by means of screws and rivet nuts.

Claims

Claims

1. Propulsion assembly (151) for an aircraft (100) comprising: - a motorization system (150) comprising a core (152) enclosed in a casing (154) and having a combustion chamber (158) and a turbine (160) provided with blades (161) rotating about a longitudinal axis (X), - a nacelle (149) in which the motorization system (150) is housed, and comprising cowls (147) including a front cowl (147b) extending opposite and in front of the turbine (160) and pierced with a window (147a) arranged at the front of the turbine (160) and a rear cowl (147d) extending at the rear of the turbine (160), - a fire barrier (192) which extends between the front cowl (147b) and the rear cowl (147d), - a supply pipe (170) intended to convey di-hydrogen, winding inside the rear cover (147d) to the rear of the turbine (160), then in a sealed manner through the fire barrier (192) to reach the outside of the front cover (147b),then through said window (147a) to the combustion chamber (158), where the supply pipe (170) is made up of several sections (182) fixed to each other and where an intermediate section (182) extends from downstream of the fire barrier (192) to downstream of the window (147a), and - a plate (183) fixed in a sealed manner to the intermediate section (182) and fixed to the front cover (147b) so as to seal said window (147a).,

2. Propulsion assembly (151) according to claim 1, characterized in that the fire barrier (192) extends transversely relative to the longitudinal axis (X) of the motorization system (150).

3. Propulsion assembly (151) according to claim 2, characterized in that the fire barrier (192) extends inside the front cover (147b) and separates the nacelle (149) into a front zone (192a) and a rear zone (192b) sealed relative to each other.

4. Propulsion assembly (151) according to one of claims 1 to 3, characterized in that it comprises an outer cover (206) fixed to the outside of the front cover (147b) of the nacelle (149) by including the part of the supply pipe (170) which is between the fire barrier (192) and the window (147a), and in that the propulsion assembly (151) has an air inlet (208) at the front of the outer cover (206), between the latter and the front cover (147b) of the nacelle (149) and an outlet (210) at the rear of the outer cover (206), between the latter and the covers (147) of the nacelle (149).

5. Propulsion assembly (151) according to claim 4, characterized in that the outlet (210) is at the front relative to said fire barrier (192).

6. Propulsion assembly (151) according to one of claims 4 or 5, characterized in that the outlet (210) is located at an upper part of the outer cover (206).

7. Propulsion assembly (151) according to one of claims 3 or 4, characterized in that it comprises a sealed flange (300) comprising a shoe (302) secured to the fire barrier (192) and having a first seat (302a) forming a half-cylinder and an extension (304) having a second seat (304a) forming a half-cylinder, securing means which ensure the fixing of the extension (304) to the shoe (302) so that the seats (302a, 304a) are joined to each other to form a cylinder, and a cylindrical seal (306) housed in said cylinder and through which the supply pipe (170) passes.

8. Propulsion assembly (151) according to one of claims 1 to 5, characterized in that it comprises a hatch mounted removably on a cover (147).

9. Aircraft (100) comprising a dihydrogen tank (172) and at least one propulsion unit (151) according to one of the preceding claims, wherein the supply pipe (170) is fluidically connected to the dihydrogen tank (172).

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