PROPULSION ASSEMBLY FOR AN AIRCRAFT
The propulsion system's innovative blower housing design with two axial sections and a removable half-shell simplifies the dismantling of tulip-mounted blades, reducing maintenance time and costs.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2022-05-20
- Publication Date
- 2026-04-03
AI Technical Summary
The existing method for dismantling tulip-mounted blower blades in aircraft propulsion systems is lengthy and complex, leading to significant aircraft immobilization time and costs.
The propulsion system incorporates a blower housing with two axial sections, comprising two half-shells, one of which is removable, allowing blades to be dismantled without removing the fan from the turbomachine by radial translation through a space created by removing the second half-shell.
Facilitates the dismantling of blower blades, reducing the time and cost associated with maintenance operations by simplifying the process.
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Abstract
Description
Title of the invention: PROPULSION ASSEMBLY FOR AN AIRCRAFT Technical field of the invention
[0001] The present invention relates to a propulsion assembly for an aircraft. Technical background
[0002] The technical background includes in particular the documents FR-A1-3 021 295, FR-Al-3 046 409, FR-A1-3 112 819, WO-A1-2022 / 018353 and WO-A1-2022 / 018355.
[0003] Conventionally, an aircraft propulsion system comprises a turbomachine surrounded by a nacelle. The turbomachine includes a gas generator comprising at least one compressor, an annular combustion chamber and at least one turbine.
[0004] In the case of a turbojet engine, the turbomachine further comprises a fan located upstream of the gas generator and driven in rotation by a rotor of the gas generator. In the case of a twin-spool turbojet, it comprises a high-pressure spool and a low-pressure spool. The high-pressure spool includes a high-pressure compressor and a high-pressure turbine whose rotors are connected together by a tubular high-pressure shaft. The low-pressure spool includes a low-pressure compressor and a low-pressure turbine whose rotors are connected together by a low-pressure shaft that passes axially through the high-pressure rotor and whose upstream end is connected, either directly or via a reduction gear, to a fan shaft.
[0005] In the present application, the terms upstream and downstream refer to the direction of gas flow in the turbomachine and propulsion assembly.
[0006] The fan is enclosed and is therefore surrounded by a fan housing. The fan housing conventionally comprises a cylindrical wall whose internal surface is covered with an abradable coating which surrounds the fan and is adapted to cooperate by friction with the tips of the fan blades.
[0007] The nacelle surrounds the fan casing and at least part of the turbomachine and generally includes an air inlet sleeve just upstream of the fan. The airflow in front of the propulsion assembly is divided into an external flow that flows around the air inlet sleeve and the nacelle, and an internal flow that enters the propulsion assembly and passes through the fan. In the case of a turbofan engine, an internal portion of this internal flow forms a primary flow and supplies the gas generator, and an external portion of this internal flow forms a secondary flow and flows around the gas generator.
[0008] The blower comprises a hub connected to the blower shaft and an annular row of blades extending around the hub and substantially radially with respect to the blower's axis of rotation. Each blade comprises a vane having a free apex at its radially outer end and a root at its radially inner end. Each blade is individually mounted on the hub by means of its root.
[0009] There are at least two types of attachment for a fan blade to a hub. According to a first type of "broached" attachment, the base of each blade has a general "bulb" or dovetail shape and is engaged in a recess of complementary shape on the outer periphery of the hub by translation along the axis of the fan. With this technology, it is understood that the blades can be mounted and dismounted individually from the upstream end of the propulsion unit or turbomachine. During a blade dismounting operation, for example, the blade is detached from the hub and removed by axial translation upstream, this removal being carried out inside the nacelle and the air intake sleeve of the propulsion unit.
[0010] According to a second type of attachment, the base of each blade has a "tulip" shape and includes a bulge engaged in a radial housing of the hub by radial translation relative to the axis of the blower. This technology is generally used when the blower blades have variable pitch, that is, when each blade has an adjustable orientation around a radial axis, called the pitch axis. A variable pitch system is then associated with the base of each blade, in the aforementioned housing of the hub, and the blower pitch systems are generally connected to the same actuator for moving the blades around their pitch axes.
[0011] Unlike previous technology, tulip-mounted blades must be mounted and dismounted individually from outside the hub by radial translation. During the dismantling operation of a blade 10, for example, as illustrated in Figures 1 to 3, the fan 12, comprising the hub 14 and the blades 10, must be separated from the rest of the turbomachine 16 or the propulsion assembly to be moved upstream and extracted from the fan housing 18 or even from the air inlet sleeve (not shown). The blade 10 is then separated from the hub 14 and removed by radial translation outwards (arrow Fl).
[0012] As can be understood, this operation is long and complex and results in a significant period of immobilization of the aircraft equipped with this turbomachine and propulsion system.
[0013] There is therefore a need to identify a solution to facilitate the dismantling of a bulb-attached blower blade, in order to reduce the time and cost of this dismantling operation. Summary of the invention
[0014] The invention proposes a propulsion system for an aircraft, this propulsion system comprising:
[0015] - a gas generator comprising at least one compressor, an annular chamber combustion and at least one turbine,
[0016] - a blower located upstream of the gas generator and driven in rotation by a the rotor of the gas generator around an axis, the blower comprising a hub and an annular row of blades extending around the hub, each of which has a foot mounted by radial translation in a housing in the hub,
[0017] - a blower housing extending around the blower, the blower housing comprising an external cylindrical wall and an internal abradable annular coating,
[0018] - a nacelle extending around the blower housing and at least part of the gas neutron,
[0019] characterized in that the blower housing comprises two axial sections, respectively upstream and downstream, the upstream axial section comprising two half-shells which each extend around the axis and whose circumferential ends are joined, each of these half-shells comprising a part of the external cylindrical wall and a part of the abradable coating, a first of these half-shells being integral with the downstream axial section, and a second of these half-shells being removable and fixed at the level of its circumferential ends on the circumferential ends of the first half-shell.
[0020] The invention thus proposes a solution for dismantling a fan blade without dismantling and removing the fan from the turbomachine or propulsion assembly. The second half-shell forms part of the fan casing insofar as it comprises both a portion of the cylindrical wall and a portion of the abradable coating. This half-shell may include other elements such as, for example, carbon plies (fabrics or sheets). The abradable coating is, for example, of the honeycomb type and comprises a plurality of cells.
[0021] The assembly according to the invention may comprise one or more of the following features, taken individually or in combination with each other:
[0022] - each of the half-shells has an angular extent around the axis which is This extent, measured for example between 90 and 190°, and preferably between 160 and 190°, is measured, for example, between the two circumferential ends of a half-shell.
[0023] - the circumferential ends of the half-shells are fixed together by bridling, that is to say by means of bridles,
[0024] - each of the half-shells comprises at each of its circumferential ends rentielles a longitudinal flange which extends along the axis and radially outwards relative to the axis, and which includes through holes for the passage of screws or bolts,
[0025] - the circumferential ends of the half-shells overlap each other in radial direction,
[0026] - the second half-shell comprises an upstream circumferential edge and a circular edge downstream conferential, the upstream circumferential edge extending in line with an upstream circumferential edge of the first half-shell, the downstream circumferential edge extending opposite an upstream circumferential edge of the downstream section,
[0027] - the nacelle includes an annular air inlet sleeve located upstream of the blower and at least one annular cowling situated around the blower housing, the cowling comprising third and fourth half-shells which each extend around the axis and around said first and second half-shells respectively, the third half-shell being articulated by one of its circumferential ends around another axis (B) parallel to said axis and being movable from a cowling closed position to a cowling open position and access to the second half-shell for the purpose of its dismantling and removal,
[0028] — a variable adjustment system is associated with the base of each of the blades, in the aforementioned hub housing,
[0029] — the first half-shell is formed in one piece with the downstream axial section.
[0030] The invention also relates to a method for dismantling a blower blade in a propulsion assembly as described above, comprising the steps of:
[0031] a) dismantling and removal of the second half-shell,
[0032] b) dismantling the blade and removing the blade through a space left free by this second half-shell.
[0033] Step a) may be preceded by a step j) of moving the third shell from its closed position to its open position.
[0034] Step j) may be preceded by a step i) of dismantling and removing the air intake sleeve. Brief description of the figures
[0035] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:
[0036] [Fig-1] Fig. 1 is a schematic perspective view of part of a tower aircraft engine, according to the prior art of the invention,
[0037] [Fig.2] Fig.2 is a schematic perspective view of the tur- part The blower blade assembly of [Fig. 1] illustrates a first step in the dismantling operation of a blower blade,
[0038] [Fig.3] [Fig.3] is a schematic perspective view of the turbine part of [Fig.1] and illustrates a second step in a blower blade dismantling operation,
[0039] [Fig.4] Fig.4 is a schematic perspective view of a propulsion assembly, according to one embodiment of the invention,
[0040] [Fig.5] [Fig.5] is a larger-scale view of part of [Fig.4] and illustrates a circumferential end of a removable half-shell of the turbomachine blower housing,
[0041] [Fig.6] [Fig.6] is a view similar to that of [Fig.4] and illustrates a step in a blower blade dismantling operation,
[0042] [Fig.7] [Fig.7] is a view similar to that of [Fig.4] and illustrates the operation of dismantling a blower blade, and
[0043] [Fig.8] The [Fig.8] is a view similar to that of the [Fig.4] and illustrates another step in the operation of dismantling a blower blade. Detailed description of the invention
[0044] Figures 1 to 3 have already been described above and illustrate the technique prior to the present invention.
[0045] Figures 4 to 8 represent a propulsion unit 54 for an aircraft, this propulsion unit comprising a turbomachine 20 of which a fan module 22 is more particularly illustrated in the drawing.
[0046] As mentioned above, the turbomachine 20 comprises a gas generator G including at least one compressor CCI, an annular combustion chamber CC2 and at least one turbine T.
[0047] The turbomachine 20 further includes a blower 24 which is located upstream of the gas generator G and which is driven in rotation by a rotor of the gas generator G around an axis A.
[0048] The blower 24 is surrounded by a blower housing 26 which conventionally comprises a cylindrical wall 28 whose internal surface is covered with an abradable coating 30. This coating 30 surrounds the blower 24 and is able to cooperate by friction with the tips of the blades 32 of the blower 24.
[0049] The blower 24 further includes a hub 34 which carries the blades 32, these blades 32 extending around the hub 34 and substantially radially with respect to the axis A. Each of the blades 32 includes a blade 36 having a free apex 38 at its radially external end and a foot 40 at its radially internal end. Each of the blades is mounted individually on the hub 34 by a "tulip foot" type attachment.
[0050] The foot 40 of each of the blades 32 includes a bulge called a "tulip foot" and is engaged in a radial housing 42 of the hub 34, by radial translation with respect to the axis A. A variable shimming system 44 is associated with the foot 40 of each of the blades 32, in the housing 42 of the hub.
[0051] The blower module 22 is here formed by the blower 24, with its hub 34 and its blades 32 in particular, and the blower housing 26.
[0052] One of the particularities of the blower housing 26 is that it comprises two axial sections, respectively upstream 46 and downstream 48.
[0053] The downstream axial section 48 is monobloc over 360° around the axis A, and extends axially downstream of the blower 24.
[0054] The upstream axial section 46 is divided into two parts, more precisely into two half-shells 46a, 46b, each extending around the axis A and arranged end to end. The upstream axial section 46 extends exactly around the blower 24.
[0055] The half-shells 46a, 46b each have an angular extent around axis A which is between 90° and 190°, and preferably between 160° and 190°, and their circumferential ends are joined, preferably directly. In the case where the circumferential ends of the half-shells 46a, 46b are directly joined, their cumulative angular extents would be 360° or less.
[0056] A portion of the nacelle 58, and in particular of the cowling 62, may be fixed. Either one of the half-shells is fixed and the other is movable, or both half-shells are movable and their combined angular range may be less than 360°. In the latter case, a fixed portion extending, for example, over 10° at 90° is located between the half-shells and is preferably situated around the connection to the aircraft, i.e., at the level of a pylon of the propulsion assembly. Each of these half-shells 46a, 46b comprises a portion of the outer cylindrical wall 28 and a portion of the abradable coating 30.
[0057] A first of these half-shells 46a is integral with the downstream axial section 48 and for example formed in one piece with the downstream axial section 48.
[0058] The second half-shell 46b is removable and fixed at its circumferential ends to the circumferential ends of the first half-shell 46a.
[0059] The second half-shell 46b, for example, has a length L1 along axis A that represents between 30 and 60% of a length L2 of the fan casing 26 (Figures 4 and 5). L1 can alternatively represent between 80% and 200% of a maximum chord C of one of the blades 32. The maximum chord C of a blade 32 is the maximum distance between the leading edge and the trailing edge of that blade, measured in a plane perpendicular to dicular to an axis of blade elongation which can be considered as its alignment axis.
[0060] The second half-shell 46b comprises two circumferential edges, respectively upstream 46b1 and downstream 46b2, and two lateral edges 46b3.
[0061] The upstream circumferential edge 46b 1 is located in the extension of an upstream circumferential edge 26a of the first half-shell 46a and the rest of the blower housing 26. The downstream circumferential edge 46b2 is located opposite an upstream circumferential edge 48a of the downstream section 48.
[0062] The lateral edges 46b3 located at the circumferential ends of the half-shell 48 have fixing flanges 50. The flanges 50 extend along the axis A and radially outwards with respect to the axis A. They include through holes for the passage of screws 52 or bolts which pass through similar flange holes of the first half-shell 46a.
[0063] The propulsion assembly 54 includes a nacelle 58 which extends around the blower casing 26 and at least part of the gas generator G.
[0064] The nacelle 58 includes an annular air inlet sleeve 60 which is located upstream of the blower 24 and at least one annular cowling 62 located around the blower housing 26.
[0065] The cowling 62 comprises third and fourth half-shells 62a, 62b which each extend around the axis A and around respectively the first and second half-shells 46a, 46b.
[0066] The third half-shell 62a is articulated by one of its circumferential ends 62al around an axis B parallel to the axis A and is mobile from a closed position of the cover 62 to an open position of the cover 62 and access to the second half-shell 46b for the purpose of its dismantling and removal.
[0067] The half-shells 62a, 62b of the hood 62 each have an angular extent around the axis A which is between 90 and 190°, and preferably between 160 and 190°, and their circumferential ends are joined, preferably directly.
[0068] The present invention also relates to a method of dismantling a blower blade 32 in a propulsion assembly as illustrated in figures 6 to 8.
[0069] The method may include a preliminary step j) of moving the third shell 62a from its closed position to its open position.
[0070] This process comprises the following steps:
[0071] a) dismantling and removal of the second half-shell 46b (see figures 6 and 7), and
[0072] b) dismantling of the blade 32 and removal of the blade 32 through a space left free by this second half-shell 46b (cf. [Fig.8]).
[0073] In step a), the screws 52 securing the flanges 50 are unscrewed and removed to separate the half-shell 46b from the half-shell 46a. The half-shell 46b is then removed by displacement, for example axially upstream, with respect to the rest of the propulsion assembly 54.
[0074] To demonstrate other blades 32, it is then sufficient to rotate the blower so that the blades in question are located at the level of the free space.
[0075] Step j) may be preceded by a step i) of dismantling and removing the air inlet sleeve 60. The air inlet sleeve 60 is dismantled and then removed from the propulsion assembly by axial translation upstream.
Claims
Demands
1. Propulsion assembly (54) for an aircraft, said propulsion assembly (54) comprising: - a gas generator (G) comprising at least one compressor (CCI), one annular combustion chamber (CC2) and at least one turbine (T), - a blower (24) located upstream of the gas generator and driven in rotation by a rotor of the gas generator (G) around an axis (A), the blower (24) comprising a hub (34) and an annular row of blades (32) which extend around the hub (34) and which each comprise a foot (40) mounted by radial translation in a housing (42) of the hub (34), - a blower housing (26) extending around the blower (24), the blower housing (26) comprising an external cylindrical wall (28) and an internal abradable annular coating (30), - a nacelle (58) extending around the blower housing (26) and at least part of the gas generator, characterized in that the blower housing (26) comprises two axial sections, respectively upstream (46) and downstream (48), the upstream axial section (46) comprising two half-shells (46a, 46b) which each extend around the axis (A) and whose circumferential ends are joined, each of these half-shells (46a, 46b) comprising a part of the external cylindrical wall (28) and a part of the abradable coating (30), a first of these half-shells (46a) being integral with the downstream axial section (48), and a second of these half-shells (46b) being removable and fixed at its circumferential ends to the circumferential ends of the first half-shell (46a),and in that the nacelle (58) comprises an annular air inlet sleeve (60) located upstream of the blower (24) and at least one annular cowling (62) located around the blower housing (26), the cowling (62) comprising third and fourth half-shells (62a, 62b) which each extend around the axis (A) and around said first and second half-shells (46a, 46b) respectively, the third half-shell (62a) being articulated by one of its circumferential ends around another axis (B) parallel to said axis (A) and being movable from a closed position of the cowling (62) to an open position of the cowling (62) and access to the second half-, shell (46b) with a view to its dismantling and removal.
2. Propulsive assembly (54) according to claim 1, wherein each of the half-shells (46a, 46b) has an angular extent around the axis (A) which is between 90 and 190°, and preferably between 160 and 190°.
3. Propulsive assembly (54) according to claim 1 or 2, wherein the circumferential ends of the half-shells (46a, 46b) are fixed together by flanges.
4. Propulsion assembly (54) according to claim 3, wherein each of the half-shells (46a, 46b) comprises at each of its circumferential ends a longitudinal flange (50) which extends along the axis (A) and radially outwards with respect to the axis (A), and which comprises through holes for the passage of screws (52) or bolts.
5. Propulsive assembly (54) according to any one of the preceding claims, wherein the circumferential ends of the half-shells (46a, 46b) overlap each other in the radial direction.
6. Propulsive assembly (54) according to any one of the preceding claims, wherein the second half-shell (46b) comprises an upstream circumferential edge (46b 1) and a downstream circumferential edge (46b2), the upstream circumferential edge (46b 1) extending in the continuation of an upstream circumferential edge (26a) of the first half-shell (46al), the downstream circumferential edge (46b2) extending opposite an upstream circumferential edge (48a) of the downstream section (48).
7. Method of dismantling a blower blade (32) in a propulsion assembly (58) according to any one of the preceding claims, wherein it comprises the steps of: a) dismantling and removing the second half-shell (46b), b) dismantling the blade (32) and removing the blade (32) through a space left free by this second half-shell (46b).
8. A method according to claim 7, wherein step a) is preceded by a step j) of moving the third half-shell (62a) from its closed position to its open position.
9. Method according to claim 8, wherein step j) is preceded by a step i) of dismantling and removing the air inlet sleeve (60).