AIRCRAFT PROPULSION ASSEMBLY AND METHOD FOR ADAPTING A PROPULSION ASSEMBLY
By inserting an axial extension between the intermediate housing and the thrust reverser, the aircraft propulsion system can adapt its easement paths, enabling seamless transitions between under-wing and wing-mounted installations without modifying existing components.
Patent Information
- Application Number
- FR2020012885
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2020-12-09
- Publication Date
- 2025-03-28
- Estimated Expiration
- 2040-12-09
Smart Images
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Abstract
Description
Title of the invention: AIRCRAFT PROPULSION ASSEMBLY AND METHOD FOR ADAPTATION OF A PROPULSION ASSEMBLY Technical field of the invention
[0001] The present invention relates to an aircraft propulsion unit and a method of adapting a propulsion unit. Technical background
[0002] An aircraft is powered by at least one propulsion assembly, in particular of the type of those described in documents FR-A1-2 869 290, FR-A1-2 875 855, FR-A1-2 887 931, FR-A1-2 920 137, FR-A1-2 920 198 and FR-A1-3 087 497.
[0003] Such a propulsion unit comprises a turbomachine, for example of the turbojet type, housed in a nacelle. The turbojet, for example of the double-flow type, is capable of generating, by means of a fan, a flow of hot gases (also called the primary flow) and a flow of cold air (also called the secondary flow). The primary flow flows inside a gas generator of the turbojet, which comprises at least one compressor, an annular combustion chamber and at least one turbine. The secondary flow flows in a vein located outside the gas generator and inside the nacelle. The primary and secondary flows flow from upstream to downstream in the propulsion unit.
[0004] The nacelle of the propulsion unit generally has a tubular structure comprising an upstream section, or air inlet, a middle section intended to surround the fan, and a downstream section which is intended to surround the gas generator of the turbojet and which is connected by thrust reversal means to an ejection nozzle located downstream.
[0005] The thrust reverser means, also called thrust reversers, make it possible, when the aircraft lands, to improve its braking capacity by redirecting upstream a majority fraction of the thrust generated by the propulsion unit.
[0006] In this phase, the thrust reversal means generally obstruct the secondary flow stream and direct the latter upstream, thereby generating counter-thrust which adds to the braking of the aircraft wheels.
[0007] A first type of propulsion unit is intended to be installed on the fuselage and / or on / under the wing of the aircraft by means of a suspension pylon, also called a reactor mast. The fixing device makes it possible, for example, to suspend the nacelle under the wing.
[0008] A second type of propulsion unit is provided to be installed on the fuselage and / or on / under the aircraft wing by means of a structural box. The fixing device comprises, for example, a lower beam mounted on a structural box fixed to the aircraft wing.
[0009] For each type of propulsion unit, the services of the propulsion unit (in particular air lines, oil lines, fuel lines, electrical harnesses, etc.) making it possible to connect the propulsion unit to the wing, have specific positions provided depending on whether the nacelle is located on or under the wing.
[0010] A propulsion unit initially intended to be installed under the wing will therefore have servitudes located on the top of the nacelle (or at 12 o'clock by analogy with the dial of a clock) in order to connect under the wing. Conversely, a propulsion unit initially intended to be installed on the wing will have servitudes located on the underside of the nacelle (or at 6 o'clock by analogy with the dial of a clock) in order to connect to the wing.
[0011] Thus, a propulsion unit initially intended to be installed under the wing cannot be installed on the wing (and vice versa) without heavily modifying it, in particular in such a way as to provide for a complete change in the route of the services and the spaces necessary for their passage and their connections to the wing and to the aircraft.
[0012] The present invention provides a solution to at least some of the problems mentioned above. Summary of the invention
[0013] The invention relates to an aircraft propulsion assembly, comprising:
[0014] - a fan configured to generate an air intake flow,
[0015] - a gas generator located downstream of the blower and comprising a primary vein flow of a first part of said flow,
[0016] - a fan housing extending around the fan and at least a portion of the gas generator, and defining around the gas generator a secondary flow stream for a second part of said flow, the fan casing being connected to the gas generator by an intermediate casing comprising two annular shells, respectively internal and external, connected to each other by radial arms extending into the secondary stream,
[0017] - a nacelle mounted on the fan casing and comprising, upstream of the casing of fan, an inlet sleeve for said air flow, and downstream of the fan casing, a thrust reverser, this thrust reverser comprising two annular partitions, respectively internal and external, the external partition comprising an upstream annular edge which is configured to be connected to a downstream annular edge of the external shell of the intermediate casing, and the internal partition comprising an upstream annular edge which is configured to be connected to a downstream annular edge of the internal shell of the intermediate casing,
[0018] characterized in that it further comprises an axial extension interposed between the intermediate casing and the thrust reverser, this extension comprising two annular walls, respectively internal and external, the internal wall comprising an upstream annular edge for connection to the downstream edge of the internal shell of the intermediate casing, and a downstream annular edge for connection to the upstream edge of the internal partition, and the external wall comprising an upstream annular edge for connection to the downstream edge of the external shell of the intermediate casing, and a downstream annular edge for connection to the upstream edge of the external partition.
[0019] The invention thus proposes to insert an extension between the intermediate casing and the thrust reverser, in particular so as to be able to pass ancillaries around this extension. The latter is an adaptation part which makes it possible to longitudinally offset the interfaces and reconstitute the secondary vein without making modifications to the existing propulsion assembly while creating a free space which can be occupied by the ancillaries. Thus, the path of the ancillaries can be modified, by passing through a new space created by the extension. It will then be possible to use this space to lower the ancillaries from the upper part of the propulsion assembly or on the contrary to raise them from the lower part of the productive assembly, depending on the choice of the new positioning of the propulsion assembly.Thus, thanks to the invention, a propulsion unit intended for positioning under the wing of an aircraft can be positioned on the wing, or vice versa, without modifying the existing parts of the engine and only by adding an extension.
[0020] The propulsion unit, according to the invention, may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another:
[0021] - the upstream edges of the internal wall and the internal partition are identical, the edges upstream of the outer wall and the outer partition are identical, the downstream edges of the inner wall and the inner shell are identical, and the downstream edges of the outer wall and the outer shell are identical;
[0022] - the upstream edges of the internal and external walls are respectively complementary downstream edges of these walls;
[0023] - the downstream edges of the internal wall and the internal shell each comprise a cylindrical rim facing downstream, and / or the downstream edges of the outer wall and the outer shell each comprise an annular groove facing radially outwards and preferably having a general V-shape in section;
[0024] - the extension is formed by the assembly of at least two half-pieces fixed to each other the other in a fixing plane substantially parallel to a longitudinal axis of the propulsion assembly, each of the half-pieces comprising an angular sector of the internal wall and an angular sector of the external wall, circumferential ends of the sector of the internal wall being connected to circumferential ends of the sector of the external wall by connecting walls substantially parallel to said plane;
[0025] - said plane has a general vertical orientation and said connecting walls are located respectively at 12 o'clock and 6 o'clock by analogy with the face of a clock;
[0026] - at least one easement of generally curved shape extends around the extension, for example about 180°;
[0027] - said at least one easement is chosen from an air duct, a duct oil, fuel line and electrical harness;
[0028] - the propulsion assembly comprises a device for fixing the propulsion assembly on a wing of an aircraft, this device comprising:
[0029] - a pylon located in the nacelle at 12 o'clock by analogy with the dial of a clock and extending along a longitudinal axis of the propulsion unit, this pylon comprising members for attachment to the fan casing and to the gas generator, and
[0030] - at least one hoop or ring extending at least partly around the generator of gas, for example, upstream of the extension, from the pylon to a beam located at 6 o'clock, this beam extending along a longitudinal axis of the propulsion unit and being configured to be fixed to the wing.
[0031] The invention also relates to a method for adapting a propulsion unit, this propulsion unit being configured to be mounted under a wing of an aircraft and being adapted to allow its mounting on a wing of an aircraft, the method comprising the steps consisting of:
[0032] a) preparing a propulsion unit comprising:
[0033] - a blower configured to generate an air inlet flow,
[0034] - a gas generator located downstream of the blower and comprising a primary vein flow of a first part of said flow,
[0035] - a fan housing extending around the fan and at least a portion of the gas generator, and defining around the gas generator a secondary flow stream for a second part of said flow, the fan casing being connected to the gas generator by an intermediate casing comprising two annular shells, respectively internal and external, connected to each other by radial arms extending into the secondary stream,
[0036] - a nacelle mounted on the fan casing and comprising, upstream of the casing of fan, an inlet sleeve for said air flow, and downstream of the fan casing, a thrust reverser, this thrust reverser comprising two annular partitions, respectively internal and external, the external partition comprising an upstream annular edge which is configured to be connected to a downstream annular edge of the external shell of the intermediate casing, and an internal partition comprising an upstream annular edge which is configured to be connected to a downstream annular edge of the internal shell of the intermediate casing, and
[0037] b) inserting an axial extension between the intermediate casing and the thrust reverser, this extension comprising two annular walls, respectively internal and external, the internal wall comprising an upstream annular edge for connection to the downstream edge of the internal shell of the intermediate casing, and a downstream annular edge for connection to the upstream edge of the external casing, and the external wall comprising an upstream annular edge for connection to the downstream edge of the external shell of the intermediate casing, and a downstream annular edge for connection to the upstream edge of the thrust reverser. Brief description of the figures
[0038] Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which reference will be made to the appended drawings in which:
[0039] [fig. 1] [fig.l] is a schematic representation in longitudinal section of a propulsion unit according to the invention;
[0040] [fig.2] [fig.2] is a detailed schematic representation in half-longitudinal section tudinal of an extension installed downstream of the intermediate casing;
[0041] [fig.3] [fig.3] is a schematic perspective representation of the inter casing mediator;
[0042] [fig.4] [fig.4] is a schematic perspective representation of an inverter of thrust of the propulsion unit;
[0043] [fig.5] [fig.5] is a schematic perspective representation of the extension installed downstream of the intermediate casing;
[0044] [fig.6] [fig.6] is a detailed perspective schematic representation of a propulsion unit with a fixing device for installation on an aircraft wing; and
[0045] [fig.7] [fig.7] is a schematic perspective representation of a set propulsive with a fixing device for installation on an aircraft wing. Detailed description of the invention
[0046] [fig.l] represents an aircraft propulsion unit 1 which extends along a longitudinal axis X. Such an aircraft propulsion unit 1 comprises, in known manner, a fan 10, a gas generator 20, a fan casing 30 and a nacelle 50.
[0047] The gas generator 20 comprises a low pressure compressor 1a, a high pressure compressor 1b, an annular combustion chamber 1c, a high pressure turbine pressure Id, a low pressure turbine le and an exhaust nozzle Ih.
[0048] The blower 10 is configured to generate an air inlet flow F around the gas generator 20.
[0049] The gas generator 20 comprises a primary flow vein 21 of a first part of said flow F, called primary flow.
[0050] Upstream and downstream are defined here with respect to the normal flow direction of the fluid F (from upstream to downstream) through the propulsion assembly 1. Furthermore, unless otherwise specified, the adjectives interior / internal and exterior / external are used with reference to a radial direction so that the internal part (i.e. radially interior) of an element is closer to the X axis than the external part (i.e. radially exterior) of the same element.
[0051] The fan casing 30 extends around the fan 10 and at least a portion of the gas generator 20, and defines around the gas generator 20 a secondary flow vein 22 of a second portion of said flow F, called secondary flow.
[0052] The fan casing 30 is connected to the gas generator 20 by an intermediate casing 40. The intermediate casing 40 comprises two annular shells 41, 42, respectively internal 41 and external 42, connected to each other by radial arms 43 extending in the secondary vein 22.
[0053] The nacelle 50 is mounted on the fan casing 30 and comprises, upstream of the fan casing 30, an inlet sleeve 51 for the air flow F, and downstream of the fan casing 30, a thrust reverser 60.
[0054] The thrust reverser 60 comprises two annular partitions 63, 64, respectively internal 63 and external 64, delimiting a section of the secondary vein 22.
[0055] The external partition 64 comprises an upstream annular edge 61 which is configured to be connected to a downstream annular edge 45 of the external shell 42 of the intermediate casing 40. The internal partition 63 comprises an upstream annular edge 62 which is configured to be connected, in particular by support, to a downstream annular edge 44 of the internal shell 41 of the intermediate casing 40.
[0056] According to the invention, the propulsion unit 1 further comprises an axial extension 100 interposed between the intermediate casing 40 and the thrust reverser 60. This extension 100 comprises two annular walls 101, 102, respectively internal 101 and external 102. The internal wall 101 comprises an upstream annular edge 104 for connection to the downstream edge 44 of the internal shell 41 of the intermediate casing 40, and a downstream annular edge 105 for connection to the upstream edge 62 of the internal partition 63. The external wall 102 comprises an upstream annular edge 106 for connection to the downstream edge 45 of the external shell 42 of the intermediate casing 40, and a downstream annular edge 107 for connection to the upstream edge 61 of the external partition 64.
[0057] This extension 100 forms an annular assembly making it possible to axially shift the interfaces between the intermediate casing 40 and the thrust reverser 60 to free up a space allowing the passage of services 140, in particular between 12 o'clock and 6 o'clock by analogy with the dial of a clock, around the external wall 102 of the extension 100. It is thus possible, thanks to the invention, to change the path of the services, in particular to make them go down from 12 o'clock to 6 o'clock, in particular with the aim of being able to adapt a propulsion unit intended to be fixed under an aircraft wing, in order to allow its fixing above the wing, or vice versa.
[0058] The extension 100 separates the intermediate casing 40 from the thrust reverser 60 initially fixed to each other and will in particular cause an extension of the axial dimension of the propulsion unit. This can result in particular in a modification of the aerodynamics and the drag of the propulsion unit. The parts adjacent to the extension 100, that is to say here in particular the intermediate casing 40 and the thrust reverser 60, are not modified. The invention thus makes it possible to change the path of the ancillaries without changing the existing parts of the propulsion unit 1, except for the fan cowls 160 on the nacelle 50 to take into account the extension of said propulsion unit.
[0059] As illustrated in [fig.2], the upstream edge 104 of the inner wall 101 of the extension 100 and the upstream edge 62 of the inner partition 63 are identical. Also, the upstream edge 106 of the outer wall 102 of the extension 100 and the upstream edge 61 of the outer partition 64 are identical. In addition, the downstream edge 105 of the inner wall 101 of the extension 100 and the downstream edge 44 of the inner shell 41 are identical. Furthermore, the downstream edge 107 of the outer wall 102 of the extension 100 and the downstream edge 45 of the outer shell 42 are identical.
[0060] The upstream edge 104 of the internal wall 101 of the extension 100 is complementary to the downstream edge 105 of this internal wall 101 and therefore also to the downstream edge 44 of the internal shell 4L
[0061] The upstream edge 106 of the external wall 102 is complementary to the downstream edge 107 of this external wall 102 and therefore also to the downstream edge 45 of the external shell 42.
[0062] The downstream edges 105, 44 of the inner wall 101 and of the inner shell 41 each comprise a cylindrical rim 110 oriented downstream, in particular called the support-seal interface. The cylindrical rim 110 of the inner shell 41 is configured to receive the upstream edge 104 of the inner wall 101 and the cylindrical rim 110 of the inner wall 101 is configured to receive the upstream edge 62 of the inner partition 63. Annular sealing gaskets may be mounted between the rims 110 and the edges 104, 62.
[0063] The downstream edges 107, 45 of the outer wall 102 and of the outer shell 42 each comprise an annular groove 111 oriented radially outwards and preferably having a general V-shaped section. Such a V-shaped groove interface is called in particular “V-groove” interface in English terminology, and is known per se as for example the assembly described in document US4283028A. The annular groove 111 of the external ferrule 42 is configured to receive the upstream edge 106 of the external wall 102, in particular a lug 113 of the upstream edge 106 of the external wall 102. The annular groove 111 of the external wall 102 is configured to receive the upstream edge 61 of the external partition 64, in particular a lug 113 of the upstream edge 61 of the external partition 64. Advantageously, a seal can be provided in the bottom of each annular groove 111, so as to be compressed by the corresponding lug 113 when the extension 100 is put in place.
[0064] In an alternative not shown, the cylindrical rim support-seal interface 110 of the downstream edges 105, 44 of the inner wall 101 and of the inner ferrule 41 could be replaced by a “V-groove” interface. In other words, the cylindrical rim 110 of each of the downstream edges 105 and 44 could be replaced by a part forming radially inwardly a protrusion which has an annular groove oriented radially outwardly and having a general V-shaped section. The upstream edge 104 of the inner wall 101 and the upstream edge 62 of the inner partition 63 would then each comprise a lug of general V-shape complementary to the corresponding annular groove of the downstream edge 44 or 105. Furthermore, a seal could advantageously be provided in the bottom of each annular groove.
[0065] Thus, whether the aforementioned interfaces are of the support-seal type or of the “V-groove” type, the extension 100 can be inserted perfectly between the intermediate casing 40 and the thrust reverser 60, in particular by proposing upstream edges 104, 106 which adapt perfectly to the existing downstream edges 44, 45 of the intermediate casing 40 and in particular by proposing downstream edges 105, 107 adapting perfectly to the existing upstream edges 61, 62 of the thrust reverser 60. It is therefore not necessary to modify the interfaces of the intermediate casing 40 and the thrust reverser 60 to integrate the extension 100.
[0066] As shown in [fig.3], the inner shell 41 is connected to the outer shell 42 of the intermediate casing 40 by means of radial arms 43, here four arms 43. The arms 43 here comprise two conventional structural arms 43' and two thick arms 43” in particular in the circumferential direction. The thick arms are here arranged at 6 o'clock and 12 o'clock by analogy with the dial of a clock. The thick arms 43” are in particular wider in a circumferential direction to allow in particular the radial passage of services.
[0067] As shown in [fig.4], the thrust reverser 60 is composed of two movable parts 67, 68 independently of each other, each part 67, 68 comprising one half of the internal partition 63 going from 6 o'clock to 12 o'clock by analogy with a clock face and one half of the external partition 64 going from 6 o'clock to 12 o'clock by analogy to a clock face. In each of the moving parts 67, 68, the internal partition 63 is connected to the external partition 64 by two radial partitions 65 located respectively at 6 o'clock and 12 o'clock by analogy with the face of a clock. The partitions 63, 64, 65 of each part 67, 68 form a flow passage with a D-shaped section, hence the expression in English "D-duct" for each of these parts 67, 68 of the thrust reverser 60. The internal 63 and external 64 partitions can in particular be opened for maintenance operations. The radial partitions 65 located opposite each other and belonging to two separate moving parts 67, 68, form between them a service passage 66, in particular radial. The thrust reverser 60 thus has a service passage 66 at 6 o'clock and another at 12 o'clock by analogy with the dial of a clock.
[0068] As shown in [fig.5], the extension 100 is formed by the assembly of at least two half-pieces 120, 130, called first 120 and second 130 half-pieces. They are fixed to each other in a fixing plane P substantially parallel to a longitudinal axis X of the propulsion unit 1. The two half-pieces 120, 130 are in particular fixed by screws and fixing flanges 150, and can in particular be fixed by adjustable connecting rods or locks.
[0069] The first half-piece 120 comprises a first angular sector 121 of the internal wall 101 and a first angular sector 122 of the external wall 102.
[0070] In an identical manner, the second half-piece 130 comprises a second angular sector 131 of the internal wall 101 and a second angular sector 132 of the external wall 102.
[0071] The first half-piece 120 comprises circumferential ends 121', 121” of the first sector 121 of the internal wall 101 and circumferential ends 122', 122” of the first sector 122 of the external wall 102.
[0072] In an identical manner, the second half-piece 130 comprises circumferential ends 131', 131” of the second sector 131 of the internal wall 101 and circumferential ends 132', 132” of the second sector 132 of the external wall 102.
[0073] In the first half-piece 120, the first angular sector 121 of the internal wall 101 is connected to the first angular sector 122 of the external wall 102 by a first connecting wall 123 located at 12 o'clock by analogy with the dial of a clock and a second connecting wall 124 located at 6 o'clock by analogy with the dial of a clock. More precisely, the first connecting wall 123 makes it possible to connect the circumferential end 121' of the first angular sector 121 of the internal wall 101 to the circumferential end 122' of the first angular sector 122 of the external wall 102 and the second connecting wall 124 makes it possible to connect the circumferential end 121" of the first angular sector 121 of the internal wall 101 to the circumferential end 122" of the first angular sector 122 of the external wall 102.
[0074] Similarly, in the second half-piece 130, the second sector angular sector 131 of the inner wall 101 is connected to the second angular sector 132 of the outer wall 102 by a third connecting wall 125 located at 12 o'clock by analogy with the dial of a clock and a fourth connecting wall 126 located at 6 o'clock by analogy with the dial of a clock. More precisely, the third connecting wall 125 makes it possible to connect the circumferential end 131' of the second angular sector 131 of the inner wall 101 to the circumferential end 132' of the second angular sector 132 of the outer wall 102 and the fourth connecting wall 126 makes it possible to connect the circumferential end 131" of the second angular sector 131 of the inner wall 101 to the circumferential end 132" of the second angular sector 132 of the outer wall 102.
[0075] The connecting walls 123, 124, 125, 126 are spaced circumferentially from each other, in particular to leave a passage for the services, in particular radial. The connecting walls 123, 124, 125, 126 make it possible to aerodynamically connect the thrust reverser 60 to the thick arms 43” located at 12 o'clock and 6 o'clock of the intermediate casing 40. We thus find, at the level of the thick arms 43” of the intermediate casing 40, the connecting walls 123, 124, 125, 126 of the extension 100 and the passages 66 of the thrust reverser 60, a space aligned longitudinally and of the same circumferential width at 6 o'clock and 12 o'clock, in particular so as to be able to allow the radial and / or longitudinal passage of the services 140.
[0076] As shown in Figures 6 and 7, the propulsion assembly 1 comprises a fixing device 200 for fixing the propulsion assembly 1 to a wing of an aircraft, i.e. above the wing. This device 200 comprises a pylon 201 located in the nacelle at 12 o'clock by analogy with the dial of a clock, at least one hoop or ring 204, 204' and in particular a beam 205 located at 6 o'clock by analogy with the dial of a clock. This beam 205 extends along a longitudinal axis X of the propulsion assembly 1 and is configured to be fixed to the wing. More precisely, the beam 205 is mounted on a box (not shown) connected to the wing.
[0077] The pylon 201 extends along the longitudinal axis X of the propulsion unit 1. This pylon 201 comprises fixing members not shown to the fan casing 30 and to the gas generator 20.
[0078] The device 200 comprises in particular two structural rings 204, 204', respectively a ring 204 upstream of the beam 205 and a ring 204' downstream of the beam 205. Said at least one hoop or ring 204, 204' extends at least partly around the gas generator 20, for example upstream of the extension 100, in particular around the downstream end 31 of the fan casing 30, from the pylon 201, located at 12 o'clock, to the beam 205 located at 6 o'clock, by analogy with the dial of a clock.
[0079] In the case of using a ring 204, 204', this extends all around the gas generator 20. In the case of using a hoop, the latter extends only around a part of the gas generator 20 and therefore does not go all the way around the gas generator 20.
[0080] At least one service 140, of generally curved shape, extends around the extension 100, for example over approximately 180°, in other words around the external wall 102 of the extension 100, for example along said at least one hoop or ring 204, 204'. Said at least one service 140 is in particular connected to the pylon 201 located at 12 o'clock and must descend to the beam 205, located at 6 o'clock to be connected at the level of the wing of the aircraft.
[0081] Said at least one service 140 is for example chosen from an air line, an oil line, a fuel line, an electrical harness, etc.
[0082] Openings for passage of the services 140 are provided on the intermediate casing 40, the extension 100 and / or the thrust reverser 60.
[0083] The invention also relates to a method for adapting the propulsion assembly 1 as described previously. The propulsion assembly 1 is thus configured to be mounted under a wing of an aircraft and is adapted to allow its mounting on a wing of an aircraft.
[0084] The method comprises the steps of:
[0085] a) preparing a propulsion unit comprising the elements described previously apart from the extension 100; and
[0086] b) inserting the extension 100 described previously between the intermediate casing 40 and the thrust reverser 60 as described previously.
Claims
Claims
1. Aircraft propulsion assembly (1), comprising: - a blower (10) configured to generate an air inlet flow (F), - a gas generator (20) located downstream of the blower (10) and comprising a primary flow vein (21) of a first part of said flow (F), - a fan casing (30) extending around the fan (10) and at least part of the gas generator (20), and defining around the gas generator (20) a secondary flow path (22) for a second part of said flow (F), the fan casing (30) being connected to the gas generator (20) by an intermediate casing (40) comprising two annular shells (41, 42), respectively internal (41) and external (42), connected together by radial arms (43) extending in the secondary flow path (22), - a nacelle (50) mounted on the fan casing (30) and comprising, upstream of the fan casing (30), an inlet sleeve (51) for said air flow (F), and downstream of the fan casing (30), a thrust reverser (60), this thrust reverser (60) comprising two annular partitions (63, 64), respectively internal (63) and external (64), the external partition (64) comprising an upstream annular edge (61) which is configured to be connected to a downstream annular edge (45) of the external shell (42) of the intermediate casing (40), and the internal partition (63) comprising an upstream annular edge (62) which is configured to be connected to a downstream annular edge (44) of the internal shell (41) of the intermediate casing (40), characterized in that it further comprises an axial extension (100) interposed between the casing intermediate (40) and the thrust reverser (60), this extension (100) comprising two annular walls (101, 102), respectively internal (101) and external (102),the inner wall (101) comprising an upstream annular edge (104) for connection to the downstream edge (44) of the inner shell (41) of the intermediate casing (40), and a downstream annular edge (105) for connection to the upstream edge (62) of the inner partition (63), and the outer wall (102) comprising an upstream annular edge (106) for connection to the downstream edge (45) of the outer shell (42) of the intermediate casing (40), and a downstream annular edge (107) for connection to the upstream edge (61) of the outer partition (64).,
2. A propulsion assembly (1) according to claim 1, wherein the edges upstream edges (104, 62) of the inner wall (101) and the inner partition (63) are identical, the upstream edges (106, 61) of the outer wall (102) and the outer partition (64) are identical, the downstream edges (105, 44) of the inner wall (101) and the inner shell (41) are identical, and the downstream edges (107, 45) of the outer wall (102) and the outer shell (42) are identical.
3. Propulsion assembly (1) according to claim 1 or 2, in which the upstream edges (104, 106) of the internal (101) and external (102) walls are respectively complementary to the downstream edges (105, 107) of these walls (101, 102).
4. Propulsion assembly (1) according to one of the preceding claims, in which the downstream edges (105, 44) of the inner wall (101) and of the inner shell (41) each comprise a cylindrical rim (110) oriented downstream, and / or the downstream edges (107, 45) of the outer wall (102) and of the outer shell (42) each comprise an annular groove (111) oriented radially outwards and preferably having a general V-shape in section.
5. Propulsion assembly (1) according to one of the preceding claims, in which the extension (100) is formed by the assembly of at least two half-pieces (120, 130) fixed to each other in a fixing plane (P) substantially parallel to a longitudinal axis (X) of the propulsion assembly (1), each of the half-pieces (120, 130) comprising an angular sector (121, 131) of the internal wall (101) and an angular sector (122, 132) of the external wall (102), circumferential ends (121', 121”, 131', 131”) of the sector (121, 131) of the internal wall (101) being connected to circumferential ends (122', 122”, 132', 132”) of the sector (122, 132) of the external wall (102) by connecting walls (123, 124, 125, 126) substantially parallel to said plane (P).
6. Propulsion assembly (1) according to the preceding claim, in which said plane (P) has a generally vertical orientation and said connecting walls (123, 124, 125, 126) are located respectively at 12 o'clock and 6 o'clock by analogy with the dial of a clock.
7. Propulsion assembly (1) according to one of the preceding claims, in which at least one service (140) of generally curved shape extends around the extension (100), for example over approximately 180°.
8. Propulsion assembly (1) according to the preceding claim, wherein said at least one service (140) is chosen from an air line, an oil line, a fuel line and an electrical harness.
9. Propulsion assembly (1) according to one of the preceding claims, in which it comprises a device (200) for fixing the propulsion assembly (1) to a wing of an aircraft, this device (200) comprising: - a pylon (201) located in the nacelle at 12 o'clock by analogy with the dial of a clock and extending along a longitudinal axis (X) of the propulsion unit (1), this pylon (201) comprising fixing members (202, 203) to the fan casing (30) and to the gas generator (20), and - at least one hoop or ring (204) extending at least partly around the gas generator (20), for example upstream of the extension (100), from the pylon (201) to a beam (205) located at 6 o'clock, this beam (205) extending along a longitudinal axis (X) of the propulsion assembly (1) and being configured to be fixed to the wing.
10. Method for adapting a propulsion unit (1), this propulsion unit (1) being configured to be mounted under a wing of an aircraft and being adapted to allow its mounting on a wing of an aircraft, the method comprising the steps of: a) preparing a propulsion unit (1) comprising: - a blower (10) configured to generate an air inlet flow (F), - a gas generator (20) located downstream of the blower (10) and comprising a primary flow vein (21) of a first part of said flow, - a fan casing (30) extending around the fan (10) and at least part of the gas generator (20), and defining around the gas generator (20) a secondary flow path (22) for a second part of said flow, the fan casing (30) being connected to the gas generator (20) by an intermediate casing (40) comprising two annular shells (41, 42), respectively internal (41) and external (42), connected together by radial arms (43) extending in the secondary flow path (22), - a nacelle (50) mounted on the fan casing (30) and comprising, upstream of the fan casing (30), a sleeve (51) for inlet of said air flow, and downstream of the fan casing (30), a thrust reverser (60), this thrust reverser (60) comprising two annular partitions (63, 64), respectively internal (63) and external (64), the external partition (64) comprising an upstream annular edge (61) which is configured to be connected to a downstream annular edge (45) of the shroud external (42) of the intermediate casing (40), and an internal partition (63) comprising an upstream annular edge (62) which is configured to be connected to a downstream annular edge (44) of the internal shell (41) of the intermediate casing (40), and b) inserting an axial extension (100) between the intermediate casing (40) and the thrust reverser (60), this extension (100) comprising two annular walls (101, 102), respectively internal (101) and external (102), the internal wall (101) comprising an upstream annular edge (104) for connection to the downstream edge (44) of the internal shell (41) of the intermediate casing (40), and a downstream annular edge (105) for connection to the upstream edge (62) of the internal partition (63), and the external wall (102) comprising an upstream annular edge (106) for connection to the downstream edge (45) of the external shell (42) of the intermediate casing (40), and a downstream annular edge (107) for connection to the upstream edge (61) of the external partition (64).