ENGINE UNIT FOR AN AIRCRAFT

Abstract

The invention relates to a propulsion assembly (151) for an aircraft which includes a chassis (180), a propulsion system (150) comprising a core (152) enclosed in a casing (154) and comprising a combustion chamber (158) and a turbine (160), a supply pipe (170) for conveying dihydrogen to the combustion chamber (158) and which winds outside the casing (154) opposite the turbine (160) before plunging into the combustion chamber (158) through the casing (154), and a protective cylinder (182) fixed to the chassis (180) or to the casing (154) by fastening means (184) and disposed around the casing (154) and between the supply pipe (170) and the turbine (160). With such an arrangement, a turbine blade that detaches will encounter the protective cylinder that blocks its path to the hydrogen pipeline and will then be deflected or stopped.

Description

TECHNICAL FIELD

[0001] The present invention relates to a propulsion unit for an aircraft, said propulsion unit comprising a frame fixed to a structure of a wing of the aircraft, a single-flow engine system such as a turboprop, fixed to the frame, a dihydrogen pipe which supplies the combustion chamber of the engine system with said dihydrogen and a protective cylinder fixed around the frame between the dihydrogen pipe and the turbine of the engine system. 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 typically comprises at least one propulsion unit comprising a single-flow engine system such as a turboprop. Such an engine 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. Depending on the case, the engine system also comprises a fan or 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 system also includes a frame which is attached to a structure of the aircraft's wing and thus constitutes a suspension mast under the wing.

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

[0005] This hydrogen is supplied from a tank to the combustion chamber by a hydrogen 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 hydrogen pipe passes through the frame from the wing and thus runs from the rear to the front to the combustion chamber.

[0006] To limit the impact of core temperature on the hydrogen line, it runs outside the crankcase to reach the combustion chamber through the crankcase.

[0007] In the event of an incident in the engine system, some of the turbine or compressor blades may detach from the shaft and, due to their speed, pass through the casing, risking cutting the hydrogen pipe.

[0008] Documents DE-A-24 13 507, US-A-2017 / 198604, GB-A-1 453 873 and US-A-2005 / 025615 disclose propulsion assemblies of the state of the art. STATEMENT OF THE INVENTION

[0009] An object of the present invention is to propose a propulsion assembly which comprises protection means making it possible to protect a dihydrogen pipe passing in the vicinity of the blades of the turbine of the single-flow engine system.

[0010] For this purpose, a propulsion unit is proposed for an aircraft comprising: a chassis, a powertrain system fixed to the chassis and comprising a core enclosed in a casing and comprising a combustion chamber and a turbine provided with blades rotating about a longitudinal axis, a feed pipe intended to convey dihydrogen to the combustion chamber where the feed pipe winds outside the casing opposite the turbine before plunging into the combustion chamber through the casing, and a protective cylinder fixed to the chassis or to the casing by fixing means and arranged around the casing and between the feed pipe and the turbine.

[0011] With such an arrangement, a detached turbine blade will encounter the protective cylinder blocking its path to the hydrogen pipe and will then be diverted or stopped.

[0012] Advantageously, a front end of the protection cylinder is positioned, perpendicular to the longitudinal axis, at least at the level of the blades of the turbine which are furthest forward, and the rear end of the protection cylinder is positioned, perpendicular to the longitudinal axis, at least at the level of the blades of the turbine which are furthest rearward.

[0013] Advantageously, the protective cylinder protrudes in front of the turbine blades which are furthest forward and behind the turbine blades which are furthest rearward.

[0014] According to a particular embodiment, the fixing means comprise a front fixing system arranged at a front part of the protection cylinder and two lateral fixing systems arranged on either side of a vertical median plane of the propulsion assembly, the front fixing system comprises a front connecting rod fixed in an articulated manner by a first connection point to the casing at the median plane and by a second connection point to the protection cylinder at the median plane, and each lateral fixing system comprises a lateral connecting rod fixed in an articulated manner by a first connection point to the protection cylinder and by two second connection points to the casing.

[0015] According to a particular embodiment, the fixing means comprise a front fixing system arranged at a front part of the protection cylinder and two lateral fixing systems arranged on either side of a vertical median plane of the propulsion assembly, the front fixing system comprises a front connecting rod fixed in an articulated manner by a first connection point to the chassis at the median plane and by a second connection point to the protection cylinder at the median plane, and each lateral fixing system comprises a lateral connecting rod fixed in an articulated manner by a first connection point to the chassis and by two second connection points to the protection cylinder.

[0016] According to a particular embodiment, the fixing means comprise an outer flange secured to the casing and an inner flange secured to the protection cylinder and arranged at a rear part of the protection cylinder, the inner flange rests on a front face of the outer flange and the fixing means comprise fixing elements which fix the two flanges against each other.

[0017] Advantageously, the protective cylinder consists of at least two hollow cylinder portions fixed to each other by fastening systems. Advantageously, the protective cylinder consists of an upper half-cylinder and several lower half-cylinders fixed to the upper half-cylinder by fastening systems and two neighboring lower half-cylinders are spaced apart from each other parallel to the longitudinal axis.

[0018] The invention also proposes an aircraft comprising a wing, a dihydrogen tank and at least one propulsion unit according to one of the preceding variants where the chassis is fixed to the wing and where the supply pipe is fluidically connected to the dihydrogen tank. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above-mentioned and other features of the invention will become more clearly apparent from the following description of an exemplary embodiment, said description being given in relation to the accompanying drawings, among which: Fig. 1 is a side view of an aircraft comprising a propulsion unit according to the invention, Fig. 2 is a schematic side and sectional representation of a motorization system of the propulsion unit according to the invention, Fig. 3 is a schematic representation in section along line III-III of a propulsion unit according to a first variant embodiment of the invention, Fig. 4 is a sectional view along line IV-IV of the propulsion unit of the Fig. 3 , Fig. 5 is a view similar to the Fig. 3 for a propulsion unit according to a second variant embodiment of the invention, Fig. 6 is a side view of the propulsion assembly of the Fig. 5 , Fig. 7 is a schematic side and sectional representation of a propulsion unit according to a third variant embodiment of the invention, Fig. 8 is a view similar to the Fig. 3 for a propulsion unit according to the invention with a particular protection cylinder, Fig. 9 is a side view of a propulsion unit according to the invention with a particular protection cylinder, and Fig. 10 is a view of a detail of fixing means. DETAILED PRESENTATION OF EMBODIMENT METHODS

[0020] In the following description, terms relating to a position are taken with reference to an aircraft in a forward position, that is to say as it is represented on the Fig. 1 where arrow F shows the direction of travel of the aircraft.

[0021] 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.

[0022] There Fig. 1 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 propulsion unit 151 which comprises a nacelle 149 made up of cowls 147 forming an aerodynamic exterior surface.

[0023] There Fig. 2 shows the propulsion assembly 151 which also includes a motorization system 150 which is shown schematically. The propulsion assembly 151 includes a frame 180 which ensures the attachment of the propulsion assembly 151 to a structure of the wing 104 and constitutes a suspension mast. In the embodiment of the invention presented in Fig. 2 , the chassis 180 takes the form of a cage consisting, among other things, of beams fixed to each other. The chassis 180 is fixed to the structure of the wing by fixing means known to those skilled in the art.

[0024] In the embodiment of the invention presented in the Fig. 2 , the engine system 150 is a turboprop engine which comprises a core 152 which is enclosed in a casing 154. In the embodiment of the invention presented in the Fig. 2 , the casing 154 is housed inside the chassis 180 forming a cage and it is fixed there by any suitable means known to those skilled in the art.

[0025] Outside air enters the nacelle 149 through an opening 144 provided in the cowls 147 at the front of the nacelle 149.

[0026] Inside the nacelle 149, the primary air flow 10 enters the core 152 to supply the combustion chamber 158 with oxygen.

[0027] 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 from the combustion through a nozzle. The core 152 comprises, from upstream to downstream, a compressor 156, a 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.

[0028] 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.

[0029] 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. In the embodiment of the invention presented here, the engine system 150 also comprises a gearbox 142 mounted between the turbine 160 and the propeller 162 which rotates around an axis of rotation 50 parallel to the longitudinal axis X and which is here offset relative to the longitudinal axis X. In general, the subject of the invention is applied to a engine system 150 with a primary flow 10 inside the core 152.

[0030] The propulsion assembly 151 also comprises a supply pipe 170 which makes it possible to convey dihydrogen as fuel to the combustion chamber 158 by being fluidically connected to a dihydrogen tank 172 of the aircraft 100. The supply pipe 170 thus winds from the rear of the nacelle 149 to the outside of the casing 154, thus passing opposite and off the turbine 160 before plunging into the combustion chamber 158 through the casing 154.

[0031] In the event of an incident on the motorization system 150, it may happen that the blades 161 of the turbine 160 become detached and pass through the casing 154. To protect the supply pipe 170, the propulsion assembly 151 comprises a protection cylinder 182 which is fixed to the chassis 180 by fixing means 184 and it is arranged around the casing 154 and between the supply pipe 170 and the turbine 160. The axis of the protection cylinder 182 is generally coaxial with the longitudinal axis X.

[0032] According to another embodiment, the protection cylinder 182 is fixed to the casing 154 by fixing means.

[0033] The front end of the protection cylinder 182 is positioned, perpendicular to the longitudinal axis X, at least at the level of the blades 161 of the turbine 160 which are furthest forward, and the rear end of the protection cylinder 182 is positioned, perpendicular to the longitudinal axis X, at least at the level of the blades 161 of the turbine 160 which are furthest rearward.

[0034] Thus, in the event of a blade 161 becoming detached from the turbine 160, said blade 161 will collide with the protective cylinder 182 and its path will be interrupted before it reaches the supply pipe 170.

[0035] In the event of detachment, a blade 161 of the turbine 160 may depart radially relative to the longitudinal axis X, but there may be some dispersion and it may depart forward or backward. Thus, it is preferable to extend the protection cylinder 182 beyond the blades 161 of the turbine 160 to take into account the risks of dispersion. Thus, it is preferable for the protection cylinder 182 to protrude in front of the blades 161 of the turbine 160 which are furthest forward and rearward of the blades 161 of the turbine 160 which are furthest rearward.

[0036] Due to the position of the supply pipe 170 which is at the rear relative to the combustion chamber 158, said supply pipe 170 is never located opposite the compressor 156 and it is therefore not necessary to place a protective plate. Of course, if in another configuration the supply pipe 170 is located opposite the compressor 156, a similar protective cylinder can be put in place.

[0037] Due to the bulk in the lower part of the chassis 180 where the casing 154 is housed, the supply pipe 170 preferably extends in the upper part of said chassis 180 and therefore above the casing 154.

[0038] The installation of a protective cylinder 182 around the casing 154 makes it possible, even in the event of breakage of the fixing means, to maintain the protective cylinder 182 around the casing 154 so that it still serves as protection for the supply pipe 170.

[0039] The protective cylinder 182 is made, for example, of a titanium alloy with a high specific strength such as the alloy known as Ti-6Al-4V and has, for example, a thickness of around 30 mm.

[0040] There Fig. 3 and the Fig. 4 show a first variant of the invention where the protection cylinder 182 is fixed to the casing 154 by fixing means 384.

[0041] The fixing means 384 comprise a front fixing system 302 and two lateral fixing systems 304. The front fixing system 302 is arranged at a front part 306 of the protection cylinder 182 and the lateral fixing systems 304 are arranged on either side of the vertical median plane P (XZ) of the propulsion unit 151 and at the rear of the front part 306.

[0042] The front attachment system 302 comprises a front connecting rod 308 attached in an articulated manner by a first connection point 310a to the casing 154 at the median plane P and by a second connection point 310b to the protection cylinder 182 at the median plane P. The first connection point 310a is below the second connection point 310b.

[0043] The front connecting rod 308 is inscribed in a plane perpendicular to the longitudinal axis X.

[0044] Each lateral attachment system 304 comprises a lateral connecting rod 312 fixed in an articulated manner by a first connection point 314a to the protection cylinder 182 and by two second connection points 314b-c to the casing 154 where the three connection points 314a-c of each lateral attachment system 304 are arranged in a plane parallel to the median plane P. The first connection point 314a is above the second connection points 314b-c.

[0045] There Fig. 5 and the Fig. 6 show a second variant of the invention where the protection cylinder 182 is fixed to the chassis 180 by fixing means 584.

[0046] The fixing means 584 comprise a front fixing system 502 and two lateral fixing systems 504. The front fixing system 502 is arranged at a front part 506 of the protection cylinder 182 and the lateral fixing systems 504 are arranged on either side of the vertical median plane P (XZ) of the propulsion unit 151 and at the rear of the front part 506.

[0047] The front attachment system 502 comprises a front connecting rod 508 attached in an articulated manner by a first connection point 510a to the chassis 180 at the median plane P and by a second connection point 510b to the protection cylinder 182 at the median plane P. The first connection point 510a is above the second connection point 510b.

[0048] The front connecting rod 508 is inscribed in a plane perpendicular to the longitudinal axis X.

[0049] Each lateral attachment system 504 comprises a lateral connecting rod 512 fixed in an articulated manner by a first connection point 514a to the frame 180 and by two second connection points 514b-c to the protection cylinder 182 where the three connection points 514a-c of each lateral attachment system 504 are arranged in a plane parallel to the median plane P. The first connection point 514a is above the second connection points 514b-c.

[0050] Each point of connection of the embodiments of the Figs. 3 à 6 provides at least one pivot connection, the axes of the connection points 310a-b and 510a-b of the front fixing systems 302 and 502 are parallel to the longitudinal axis X and the axes of the connection points 314a-c and 514a-c of the lateral fixing systems 304 and 504 are parallel to the transverse axis Y.

[0051] But preferably, each connection point creates a ball joint, one embodiment of which is shown in Fig. 10 .

[0052] There Fig. 10 shows a detail of each connection point 1100 between a first element 1102 and a second element 1104. The first element 1102 may be the frame 180, the casing 154 or the protection cylinder 182 and the second element 1104 is a connecting rod.

[0053] The first element 1102 comprises a two-arm yoke 1106 between which is arranged a ball joint bearing 1108 secured to the second element 1104. Each arm is pierced with a bore into which an end sleeve 1110 is inserted. A hinge pin 1112 in the form of a hollow cylindrical barrel is, on the one hand, slidably fitted into each of the end sleeves 1110, and on the other hand, force-fitted into a bore made in the ball joint bearing 1108 in order to allow pivoting of the ball joint bearing 1108 relative to the yoke around a connecting axis L.

[0054] On one side of the yoke, a screw 1114 is inserted into the hinge pin 1112 and a first flat locking washer 1116 is fitted onto the shank of the screw 1114 and interposed between the head of the screw 1114 and an end sleeve 1110, and on the other side of the yoke, a second flat locking washer 1118 is fitted onto the shank of the screw 1114 and interposed between the other end sleeve 1110 and a threaded end of the screw where a tightening nut 1120 is tightened to the desired torque on the threaded end of the screw 1114 to come against the second flat locking washer 1118 and keep the washers 1116 and 1118 pressed against the end sleeves 1110.

[0055] The assembly of the two elements to each other is finalized by the axial immobilization, along the connecting axis L, of the end sleeves 1110 and the spherical bearing 1108. This immobilization is obtained due to the compaction between the tightening nut 1120 in contact with the second locking washer 1118 and the head of the screw 1114 in contact with the first locking washer 1116.

[0056] There Fig. 7 shows a third variant of the invention where the protection cylinder 182 is fixed to the chassis 180 by fixing means 784.

[0057] The fixing means 784 comprise an outer flange 702 and an inner flange 704. In the embodiment of the invention presented in Fig. 7 , the flanges 702 and 704 are arranged at a rear portion 706 of the protection cylinder 182. But according to another embodiment of the invention not shown, they are arranged at a front portion of the protection cylinder 182. In another embodiment not shown, a pair of flanges 702, 704 is arranged at a rear portion 706 of the protection cylinder, and another pair of flanges 702, 704 is arranged at a front portion of the protection cylinder 182.

[0058] The outer flange 702 is secured to the casing 154 and the inner flange 704 is secured to the protection cylinder 182.

[0059] The protective cylinder 182 is around the casing 154 and the inner flange 704 rests on a front face of the outer flange 702. The fixing means 784 comprise fixing elements 708 which fix the two flanges 702 and 704 against each other. The fixing elements 708 are for example bolts.

[0060] In the variants presented above, the protection cylinder 182 consists of a single element but it can consist of several elements fixed to each other.

[0061] Thus, in the embodiment of the invention presented in the Fig. 8 , the protective cylinder 182 consists of at least two portions 802a-b of hollow cylinder fixed to each other by fastening systems 804.

[0062] In the embodiment of the invention presented in the Fig. 8 , there are two half-cylinders 802a-b and the fastening systems 804 are here longitudinal ribs fixed by bolts. This embodiment can be applied to all the variants described above. On the Fig. 8 , the fixing means 184 are not shown, but they may take the form of those described above.

[0063] As shown in the Fig. 9 , to lighten the protective cylinder 182, it is made up of an upper half-cylinder 902 and several lower half-cylinders 904a-c, here three in number, which are all coaxial. The upper half-cylinder 902 is full and complete over its entire length to serve as protection for the supply pipe 170 which is above. The lower half-cylinders 904a-c extend parallel to the longitudinal direction X over reduced lengths and each lower half-cylinder 904a-c is fixed to the upper half-cylinder 902 by fastening systems 906, such as for example here longitudinal ribs fixed by bolts and there are empty spaces between two consecutive lower half-cylinders 904a-c. Two neighboring lower half-cylinders 904a-c are spaced apart from each other parallel to the longitudinal axis X.

[0064] This embodiment can be applied to all the variants described above. On the Fig. 9, the fixing means 184 are not shown, but they may take the form of those described above.

Claims

1. Propulsion assembly (151) for an aircraft (100) comprising: - a chassis (180), - a motorization system (150) fixed to the chassis (180) and comprising a core (152) enclosed in a casing (154) and comprising a combustion chamber (158) and a turbine (160) provided with blades (161) rotating about a longitudinal axis (X), - a supply pipe (170) intended to convey dihydrogen to the combustion chamber (158) where the supply pipe (170) winds outside the casing (154) opposite the turbine (160) before plunging into the combustion chamber (158) through the casing (154), and - a protection cylinder (182) fixed to the chassis (180) or to the casing (154) by fixing means (184) and arranged around the casing (154) and between the feed pipe (170) and the turbine (160).

2. Propulsion assembly (151) according to claim 1, characterized in thata front end of the protection cylinder (182) is positioned, perpendicular to the longitudinal axis (X), at least at the level of the blades (161) of the turbine (160) which are furthest forward, and the rear end of the protection cylinder (182) is positioned, perpendicular to the longitudinal axis (X), at least at the level of the blades (161) of the turbine (160) which are furthest rearward.

3. Propulsion assembly (151) according to claim 2, characterized in that the protective cylinder (182) protrudes in front of the blades (161) of the turbine (160) which are furthest forward and rearward of the blades (161) of the turbine (160) which are furthest rearward.

4. Propulsion assembly (151) according to one of claims 1 to 3, characterized in thatthe fixing means (384) comprise a front fixing system (302) arranged at a front part (306) of the protection cylinder (182) and two lateral fixing systems (304) arranged on either side of a vertical median plane (P) of the propulsion assembly (151), in that the front fixing system (302) comprises a front connecting rod (308) fixed in an articulated manner by a first connection point (310a) to the casing (154) at the median plane (P) and by a second connection point (310b) to the protection cylinder (182) at the median plane (P), and in that each lateral fixing system (304) comprises a lateral connecting rod (312) fixed in an articulated manner by a first connection point (314a) to the protection cylinder (184) and by two second connection points (314b-c) to the casing (154).

5. Propulsion assembly (151) according to one of claims 1 to 3, characterized in thatthe fixing means (584) comprise a front fixing system (502) arranged at a front part (506) of the protection cylinder (182) and two lateral fixing systems (504) arranged on either side of a vertical median plane (P) of the propulsion assembly (151), in that the front attachment system (502) comprises a front connecting rod (508) attached in an articulated manner by a first connection point (510a) to the chassis (180) at the median plane (P) and by a second connection point (510b) to the protection cylinder (182) at the median plane (P), and in that each lateral fixing system (504) comprises a lateral connecting rod (512) fixed in an articulated manner by a first connection point (514a) to the chassis (180) and by two second connection points (514b-c) to the protection cylinder (182).

6. Propulsion assembly (151) according to one of claims 1 to 3, characterized in thatthe fixing means (784) comprise an outer flange (702) secured to the casing (154) and an inner flange (704) secured to the protective cylinder (182) and arranged at a rear part (706) of the protective cylinder (182), in that the inner flange (704) rests on a front face of the outer flange (702) and in that the fixing means (784) comprise fixing elements (708) which fix the two flanges (702, 704) against each other.

7. Propulsion assembly (151) according to one of claims 1 to 6, characterized in that the protective cylinder (182) consists of at least two portions (802a-b) of hollow cylinder fixed to each other by fastening systems (804).

8. Propulsion assembly (151) according to claim 7, characterized in thatthe protective cylinder (182) consists of an upper half-cylinder (902) and several lower half-cylinders (904a-c) fixed to the upper half-cylinder (902) by fastening systems (906) and in that two neighboring lower half-cylinders (904a-c) are spaced apart from each other parallel to the longitudinal axis (X).

9. Aircraft (100) comprising a wing (104), a dihydrogen tank (172) and at least one propulsion unit (151) according to one of the preceding claims where the frame (180) is fixed to the wing (104) and where the supply pipe (170) is fluidically connected to the dihydrogen tank (172).