Nacelle for a turbine engine

Abstract

The invention relates to an aircraft propulsion assembly (1) extending along a longitudinal axis (X) and comprising a turbine engine (2), a pylon (3) that connects the turbine engine (2) to the wing of the aircraft, an inner fairing (4) that surrounds the turbine engine (2), an outer fairing (5) that circumferentially surrounds the inner fairing (4) and that comprises a first cowling (10A) and a second cowling (10B) which are able to move between a closed position and an open position, and a casing (7) that circumferentially surrounds the turbine engine and is located immediately upstream of the outer fairing (5). Each of the cowlings (10A, 10B) include a proximal portion (20A, 20B) and a distal portion (30A, 30B) which circumferentially extends the proximal portion (20A, 20B) in the closed position, the proximal portions (20A, 20B) being stationary with respect to one another and with respect to the casing (7).

Description

Description Title: Nacelle for turbomachine

[0001] The present invention relates to the field of aircraft propulsion systems, in which the propulsion system comprises a turbomachine, a nacelle surrounding the turbomachine and a mast or pylon connecting the turbomachine to the aircraft.

[0002] The propulsion unit and the turbomachine extend along a longitudinal axis X, which is the axis of rotation of the turbomachine and corresponds to the direction of air and gas flow during normal operation of the propulsion unit. Upstream and downstream are defined relative to this air and gas flow direction. The turbomachine includes a gas generator, and the nacelle comprises an inner fairing and an outer fairing that radially surrounds this outer fairing. A casing circumferentially surrounds the turbomachine and is located immediately upstream of the outer fairing.

[0003] The external fairing comprises two C-shaped cowlings on either side of a first V-shaped section that divides the turbomachine in two longitudinally and includes the longitudinal X-axis. When the turbomachine is mounted under the aircraft's wing, the first V-shaped section is vertical and therefore passes through the center of the pylon. Alternatively, the turbomachine can be mounted laterally on the aircraft's fuselage. In the closed position, each cowling encloses half the circumference of the turbomachine. Each cowling has a radially external circumferential wall and a radially internal circumferential wall. In the open position, each cowling lifts radially outward to allow for turbomachine maintenance. Each cowling is hinged at its upper end to one side of the pylon by a linkage, for example, a pivot joint, which allows it to move between its closed and open positions.The open position allows maintenance of the components located under the hoods.

[0004] Thus, we know a structure for a propulsion system for an aircraft comprising on the one hand an external fairing which is intended to circumferentially surround an internal turbomachine fairing with longitudinal axis X and which includes a first hood and a second hood which extend symmetrically from upstream to downstream along the longitudinal axis X relative to a first plane V passing through the longitudinal axis X and which are capable of passing between a closed position and an open position, and on the other hand a casing which is intended to circumferentially surround the turbomachine and which is located immediately upstream of the external fairing.

[0005] This structure is described below in the case where the propulsion assembly 1 is attached below the pylon 103, with reference to Figure 7, which is a top view cross-section of the cowlings (110A, 110B) in a plane H perpendicular to the vertical axis Z and passing directly below the pylon 103. The situation is similar when the propulsion assembly is attached laterally to the pylon. In this case, the terms "upper" will be replaced by "proximal," "lower" by "distal," "vertical plane V" by "first plane V," and "vertical axis Z" by "first axis Z."

[0006] As illustrated in Figure 6, the propulsion assembly 1 comprises a turbomachine 2 and a nacelle which includes an inner fairing 104 and an outer fairing 105 that radially surrounds this inner fairing. The propulsion assembly 1 also includes a casing 107 that circumferentially surrounds the turbomachine 2 and is located immediately upstream of the outer fairing. The propulsion assembly 1 includes a bifurcation 106 located below the forward (upstream) part of the pylon 103, which has a U-shaped structure, the apex of which is directed upstream (i.e., to the left in the figure), and whose width is less than the width L of the pylon 103 above. The bifurcation 106 is integral with the casing 107, and is therefore fixed relative to the turbomachine 2. The bifurcation 106 extends vertically under the pylon 103 over a certain height, along a first axis Z which is perpendicular to the longitudinal axis X and which extends in the first plane V.The first Z-axis passes through the upstream part of pylon 103 and the cowlings (110A, 110B). The upstream airflow coming from the upstream region of turbomachine 2 is separated into a right lateral flow and a left lateral flow by the bifurcation 106.

[0007] When the hoods (11 OA, 110B) are in the closed position, the inner lateral edges (111 A, 111 B) of these hoods (110A, 110B) extend downstream from the bifurcation 106 such that the right lateral flow (respectively left lateral flow) then flows downstream into the internal space of the remaining right hood 110A (respectively left hood 110B). The internal space of the right hood 110A (respectively left hood 110B) forms a right vein W1A (respectively left hood W1B) which widens laterally from upstream to downstream. The right vein W1A (respectively left hood W1B) is delimited laterally inward (i.e., toward the vertical plane V) by the inner lateral edge 111A (respectively left hood 111B). This situation is illustrated in figure 7 which is a top view cross-section of the hoods (110A, 110B) and the bifurcation 106 in a second plane H perpendicular to the vertical axis Z and which passes under the pylon 103.The flow of gas in the internal spaces of the hoods (110A, 110B) is represented by arrows.

[0008] Figure 8(A) is a section in a vertical plane perpendicular to the longitudinal axis X, immediately downstream of bifurcation 106 (section VIII-VIII in Figure 7). Figure 7 and Figure 8(A) show the hoods (110A, 110B) in the closed position.

[0009] Figure 8(B) is similar to Figure 8(A) and shows the hoods (110A, 110B) in the open position. The hoods (110A, 110B) are hinged to the lateral sides of pylon 103 by joints (190A, 190B) to move between a closed and an open position, as illustrated in Figures 8(A) and 8(B). The second plane H passes through the upper ends (120A, 120B) of the hoods (110A, 110B) in the closed position.

[0010] Seals 150 are located between the housing 107 and the covers (110A, 110B) and are visible in Figure 7. Seals 150 are located between the covers (110A, 110B) and the junction 106 and are visible in Figures 7, 8(A) and 8(B). A seal 150 is located between the covers (110A, 110B), the junction 106 and the pylon 103 and is visible in Figures 8(A) and 8(B).

[0011] In order to improve the aerodynamic performance of the propulsion system, the aim is to minimize the space between the pylon and the cowlings of the nacelle. This results in a difficulty in positioning the seals between the hoods, the pylon, the bifurcation and the casing. Description of the invention

[0012] The present invention aims to remedy these drawbacks.

[0013] The invention aims to provide a structure comprising an external fairing and a casing for an aircraft propulsion assembly with a reduced space between the pylon and the cowlings and whose aerodynamic performance is optimized, and in which the sealing between the cowlings, the pylon, the bifurcation and the casing surrounding the engine is achieved.

[0014] This goal is achieved thanks to the fact that the first hood comprises a proximal part and a distal part which circumferentially extends this proximal part and the second hood comprises a proximal part and a distal part which circumferentially extends this proximal part, the proximal parts being fixed relative to each other and to the housing and the distal parts pivot during the transition between the closed position and the open position.

[0015] Thanks to these features, it is no longer necessary to use a dynamic seal (i.e., a seal located between parts that move relative to each other) between the cowlings and the housing, since the proximal parts of the cowlings are fixed directly to the housing. Assembling the cowlings to the housing, and the cowlings to each other, is simplified. The pivoting of the distal parts of the cowlings allows access to the turbomachine, for example, for maintenance.

[0016] For example, each of the proximal parts is fixed to the housing by a removable mechanical assembly.

[0017] Thus, the assembly and maintenance of the propulsion system are facilitated since it is possible to remove the proximal parts without removing the casing.

[0018] For example, the proximal parts are fixed to each other by a removable mechanical assembly.

[0019] Thus, the assembly and maintenance of the propulsion system are facilitated since it is possible to remove one of the proximal parts without the other proximal part.

[0020] For example, the structure includes a first joint which is located between the proximal part of the first hood and the proximal part of the second hood.

[0021] Thus, the seal between the proximal parts is improved.

[0022] For example, the proximal parts are fixed to each other in an irremovable manner.

[0023] For example, the proximal parts are fixed to the housing by a removable mechanical assembly.

[0024] For example, the structure includes a second seal which is located between the proximal parts and the housing.

[0025] Thus, the seal between the proximal parts and the casing is improved.

[0026] For example, the structure includes hood seals which are located between the proximal and distal parts and which establish a seal when the hoods are in the closed position.

[0027] This improves the seal between the proximal and distal parts. Consequently, a seal is established between the upstream and downstream veins when the flaps are in the closed position.

[0028] The invention also relates to an aircraft propulsion system extending along a longitudinal axis X, which corresponds to the direction of gas flow during normal operation of this propulsion system and which defines an upstream and a downstream section. The propulsion system comprises a turbomachine, a pylon connecting the turbomachine to the aircraft, an internal fairing surrounding the turbomachine, and a structure according to the invention. The invention also relates to an aircraft comprising a propulsion system according to the invention.

[0029] The invention will be better understood and its advantages will become more apparent upon reading the following detailed description of embodiments shown by way of non-limiting examples. The description refers to the accompanying drawings in which:

[0030] [Fig. 1] Figure 1 is a perspective view from the rear of the propulsion assembly according to the invention.

[0031] [Fig. 2] Figure 2 is a perspective view of the proximal parts of the hoods before their attachment to the crankcase of the propulsion assembly of Figure 1.

[0032] [Fig. 3] Figure 3 is a perspective view of the proximal parts of the hoods after their attachment to the crankcase of the propulsion assembly of Figure 1.

[0033] [Fig. 4] Figure 4 is a perspective view of the proximal parts of the hoods after their attachment to the crankcase of the propulsion assembly of Figure 1, with the joints between the proximal and distal parts of the hoods.

[0034] [Fig. 5] Figure 5 is a cross-sectional view of the propulsion assembly in Figure 3 in a longitudinal plane that crosses the bifurcation.

[0035] [Fig. 6] Figure 6, already described, is a perspective view from the rear of the propulsion assembly according to the prior art.

[0036] [Fig. 7] Figure 7, already described, is a cross-sectional view of portions of hoods of a propulsion assembly according to the prior art with attachment of the propulsion assembly under the pylon.

[0037] [Fig. 8] Figure 8, already described, is in (A): a cross-sectional view along plane VIII-VIII of figure 7 with the hoods in the closed position; In (B): a cross-sectional view along plane VIII-VIII of figure 7 with the hoods in the open position. Detailed description of the invention

[0038] Consider an aircraft propulsion system 1 extending along a longitudinal axis X, which corresponds to the direction of gas flow during normal operation of this propulsion system and defines an upstream (front) and a downstream (rear) end, a first side and a second side, when this propulsion system 1 is viewed from the front. In the following description, the adjectives "front" and "rear" are defined with respect to the upstream-to-downstream direction in this longitudinal direction. Due to symmetry, the letter "A" after a part number designates that part on the first right side, and the letter "B" after a part number designates that part on the second side.

[0039] Such a propulsion assembly 1, shown in Figure 1 in rear-view perspective, comprises a turbomachine 2, a pylon 3 connecting the turbomachine 2 to the aircraft wing, an inner fairing 4 surrounding the turbomachine 2, and an outer fairing 5 circumferentially surrounding the inner fairing 4. A casing 7 circumferentially surrounds the turbomachine 2 and is located immediately upstream of the outer fairing 5. The longitudinal axis X is the axis of rotation of the turbomachine 2. A portion of the inner fairing 4 is shown as a dashed line in Figure 1 because it is hidden by the outer fairing 5. The outer fairing 5 comprises a first hollow cowling 10A and a second hollow cowling 10B extending symmetrically from upstream to downstream along the longitudinal axis X with respect to a first plane V passing through the longitudinal axis X. The first hollow hood 10A and a second hood 10B are on each side of the first plane V.A first axis Z is defined, extending in the first plane V, which is perpendicular to the longitudinal axis X and which passes through the upstream part of pylon 3 and the covers (10A, 10B). A second plane H is defined, which is perpendicular to the vertical axis Z and which passes very close to pylon 3 so as to pass through the ends of the covers (10A, 10B), as illustrated in figure 1.

[0040] In the description below, pylon 3 is located above propulsion unit 1. The first plane V is therefore vertical, and the second plane H is horizontal. The cowlings (10A, 10B) are located in a horizontal plane immediately below pylon 3. The first cowling 10A is the right cowling and the second cowling 10B is the left cowling. However, the invention also covers the case where propulsion unit 1 is mounted laterally on the fuselage, in which case the pylon is lateral to the cowlings (10A, 10B), the first plane V is horizontal, and the second plane H is vertical. The description below is therefore valid for this case, with adjectives replaced as necessary. In particular, "right" is replaced by "first" and "left" is replaced by "second", "superior" is replaced by "proximal" and "inferior" is replaced by "distal".

[0041] The covers (10A, 10B) are capable of moving between a closed and an open position. In the closed position, as shown in Figure 1, each The cowlings (10A, 10B) form half of an annular shell extending from an upper end closest to pylon 3 around the inner fairing 4 to the vertical plane V. Thus, the lower end of the right cowling 10A joins the lower end of the left cowling 10B at the vertical plane V. In the open position, a portion of each of the cowlings (10A, 10B) rises radially outwards to allow access to the inner fairing 4 and the turbomachine 2 as detailed below.

[0042] Figure 2 is an exploded perspective view of the upper portions (20A, 20B) of the covers (10A, 10B) and the upper portion of the housing 7. The right cover 10A (respectively left cover 10B) has a right upper portion 20A (respectively left cover 20B) which is located below pylon 3 when the right cover 10A (respectively left cover 10B) is in the closed position. The internal space of the upper portion 20A (respectively left cover 20B) forms a right upstream vein V2A (respectively left cover V2B) which widens laterally from upstream to downstream. The right upstream vein V2A (respectively left V2B) is delimited laterally (circumferentially) medially (i.e., towards the vertical plane V) by a right internal lateral border 21A (respectively left 21B) of the right upper portion 20A (respectively left 20B). The internal lateral borders (21A, 21B) are perpendicular to the horizontal plane H in the closed position.The right upstream vein V2A (respectively left V2B) opens laterally to the outside on the right outer face 22A (respectively left 22B) of the upper part 20A (respectively left 20B). Each of the outer faces (22A, 22B) extends approximately in a radial plane to form two lips. These two lips extend parallel to the longitudinal axis X. Thus, each of the outer faces (22A, 22B) has, in a radial plane, a U-shape open upstream and with its apex oriented downstream. The region illustrated in Figure 2 is located immediately below pylon 3. The horizontal plane H is approximately the median plane of each of the upper parts (20A, 20B). Thus, the horizontal plane H, as defined, passes through the middle of the right upstream vein V2A (respectively left V2B). For clarity, joints (90A, 90B) and pylon 3 are not shown.

[0043] The upper sections (20A, 20B) are joined together at the vertical plane V that separates them. The upper sections (20A, 20B) must be joined to the pylon 3. The upper sections (20A, 20B) are fixed directly to the housing 7 in such a way that the upper sections (20A, 20B) are fixed to the housing 7. Thus, the upper sections (20A, 20B) remain fixed when the covers (10A, 10B) move from the closed to the open position. For example, the right upper section 20A and the left upper section 20B, and each of the upper sections (20A, 20B) and the housing 7, are removably joined by mechanical means, for example, by bolts and nuts. Advantageously, a first seal 51 is located between each of the upper parts (20A, 20B) in order to contribute to the sealing between these upper parts.Advantageously, alternatively or in addition, a second seal 52 is located at the interface between these upper parts (20A, 20B) and the housing 7 to contribute to sealing at this interface. The first seal 51 and the second seal 52 are visible in Figure 2 and in Figure 3, which shows the upper parts (20A, 20B) of the covers (10A, 10B) assembled with each other and with the housing 7.

[0044] Alternatively, the upper right section 20A and the upper left section 20B are permanently (i.e., immovably) joined, for example by welding. Alternatively, each of the upper sections (20A, 20B) is permanently joined to the housing 7, for example by welding.

[0045] The right cowling 10A (respectively left 10B) has a lower right portion 30A (respectively left 30B) which extends circumferentially around the turbomachine 2 (in this case downwards) from the upper right portion 20A (respectively left 20B) in the closed position. In the illustrated example, the lower portions (30A, 30B) do not extend directly under pylon 3; that is, they extend the upper portions (20A, 20B) circumferentially outside the region directly under pylon 3. In other words, in this particular example, for each cowling (10A, 10B), the boundary between the upper portion (20A, 20B) and the lower portion (30A, 30B) lies at the boundary of the region under pylon 3. The upper ends of the lower parts (30A, 30B) are shown schematically in transparent dotted lines, in the closed position, in Figure 3. For clarity, the joints (90A, 90B) and pylon 3 are not shown.

[0046] The propulsion assembly 1 includes a bifurcation 6, which is part of the casing 7 and is located under the forward (upstream) part of pylon 3 and is symmetrical with respect to the vertical plane V. The bifurcation 6 has a V-shaped structure in the horizontal plane H, with its apex pointing upstream (i.e., to the left in the figure). The width of the bifurcation 6 is less than the width L of the pylon 3 above it. The upper parts (20A, 20B) extend the bifurcation 6 downstream. The bifurcation 6 is shown as a dashed line in Figure 2 and Figure 3.

[0047] The upstream airflow from the upstream region of the turbomachine 2 is separated into a right-side and a left-side flow by bifurcation 6. When the cowlings (10A, 10B) are closed, the inner lateral edges (21A, 21B) of the upper sections (20A, 20B) extend downstream from bifurcation 6, such that the right-side flow (respectively, left-side flow) then flows downstream into the right upstream duct V2A (respectively, left upstream duct V2B). The right upstream duct V2A (respectively, left upstream duct V2B) has a U-shaped cross-section, open laterally to the outside. The bottom of the right upstream duct V2A (respectively, left upstream duct V2B) is therefore formed by the right radially inner edge 21A (respectively, left upstream edge 21B). Each of the internal lateral edges (21 A, 21 B) moves away from the vertical plane V from upstream to downstream.

[0048] The lower right portion 30A (respectively left 30B) of the right flap 10A (respectively left 10B) is hollow and has a semi-annular internal space. The internal space of the lower right portion 30A (respectively left 30B) forms a right downstream vein V3A (respectively left V3B) which extends downstream and laterally from the right upstream vein V2A (respectively left V2B) when the flaps (10A, 10B) are in the closed position.

[0049] During the transition of the covers (10A, 10B) between the closed and open positions, the lower parts (30A, 30B) move away from the upper parts (20A, 20B) by pivoting laterally outwards. The right joint 90A (respectively left 90B), by which the right cover 10A (respectively left 10B) is articulated to the right (respectively left) lateral side of the pylon 3, is located on the lower right part 30A (respectively left 30B) at its upper end. For example, this joint (90A, 90B) is located at the proximal right edge 31A (respectively left 31B) of the lower right part 30A (respectively left 30B). The right joint 90A is hidden by the pylon 3 in Figure 1. Each of the proximal edges (31 A, 31 B) has a U shape open upstream and whose apex is oriented downstream.When the hoods (10A, 10B) are in the closed position, the right proximal edge 31A (respectively left 31B) comes to be positioned opposite the right outer face 22A (respectively left 22B) of the right upper part 20A (respectively left 20B).

[0050] Advantageously, the proximal right border 31A (respectively left 31B) of the lower right portion 30A (respectively left 30B) is fitted with a right flap seal 25A (respectively left 25B) which ensures a seal between the lower right portion 30A (respectively left 30B) and the upper right portion 20A (respectively left 20B) by compression between these portions. Thus, the right flap seal 25A (respectively left 25B) ensures a seal between the upper right vein V2A (respectively left V2B) and the lower right vein V3A (respectively left V3B). These flap seals (25A, 25B) are illustrated in Figure 4. For clarity, the lower portions (30A, 30B) are not shown. The hood seals (25A, 25B) follow the contact area between the lower parts (30A, 30B) and the upper parts (20A, 20B). This contact area is formed by the proximal edges (31A, 31B) and the outer faces (22A, 22B).Thus, a portion of each of the hood seals (25A, 25B) has, for example, a U-shape along this contact area, extending around an upstream vein (V2A, V2B). In Figure 4, hood seal 25A is hidden.

[0051] For example, as illustrated in Figure 4, the hood seals (25A 25B) extend circumferentially on the housing 7 beyond the outer faces (22A, 22B) of the upper parts (20A, 20B).

[0052] Figure 5 is a cross-sectional view of the propulsion assembly 1 in the horizontal plane H visible in Figure 3. For clarity, only the upper parts are shown. (20A, 20B) and the casing 7 are illustrated, and only the references necessary for understanding the figure are indicated. The horizontal plane H passes through the midpoint of the right upstream vein V2A and the left upstream vein V2B. Thus, the horizontal plane H crosses the bifurcation 6 and passes through the midpoint of the right internal lateral border 21A and the midpoint of the left internal lateral border 21B. The upper parts (20A, 20B) extend downstream from bifurcation 6, forming a V whose apex is directed upstream.

[0053] Alternatively, the right radially internal edge 21 A and the left radially internal edge 21 B meet upstream to form the bifurcation 6 downstream of the housing 7. In this variant, the bifurcation 6 is part of the external fairing 5.

Claims

Demands

1. Structure for a propulsion assembly for an aircraft comprising, on the one hand, an external fairing (5) intended to circumferentially surround an internal fairing (4) of a turbomachine with longitudinal axis (X) and comprising a first cowling (10A) and a second cowling (10B) extending symmetrically from upstream to downstream along the longitudinal axis (X) with respect to a first plane (V) passing through said longitudinal axis (X) and capable of passing between a closed position and an open position, and on the other hand, a casing (7) intended to circumferentially surround said turbomachine and located immediately upstream of said external fairing (5),said structure being characterized in that the first hood (10A) comprises a proximal part (20A) and a distal part (30A) which circumferentially extends said proximal part (20A) in said closed position, and the second hood (10B) comprises a proximal part (20B) and a distal part (30B) which circumferentially extends said proximal part (20B) in said closed position, said proximal parts (20A, 20B) being fixed relative to each other and relative to said housing (7) and being fixed directly to said housing (7), and said distal parts (30A, 30B) pivoting during the transition between said closed position and said open position.

2. Structure according to claim 1 such that said proximal parts (20A, 20B) are fixed to each other by a removable mechanical assembly.

3. Structure according to claim 2 such that it comprises a first seal (51) which is located between said proximal part (20A) of the first hood (10A) and said proximal part (20B) of the second hood (10B)

4. Structure according to claim 1 such that said proximal parts (20A, 20B) are fixed to each other in a non-removable manner.

5. Structure according to any one of claims 1 to 4 such that said proximal parts (20A, 20B) are fixed to said housing (7) by a removable mechanical assembly.

6. Structure according to claim 5 such that it comprises a second seal (52) which is located between said proximal parts (20A, 20B) and said housing (7).

7. Structure according to any one of claims 1 to 6, comprising hood seals (25A, 25B) which are located between the proximal parts (20A, 20B) and the distal parts (30A, 30B) and which establish a seal when said hoods (10A, 10B) are in the closed position.

8. A propulsion system (1) for an aircraft extending along a longitudinal axis (X) corresponding to the direction of gas flow during normal operation of said propulsion system (1) and defining an upstream and a downstream end, said propulsion system (1) comprising a turbomachine (2), a pylon (3) connecting said turbomachine (2) to the aircraft, an internal fairing (4) surrounding said turbomachine (2), and a structure according to any one of the preceding claims.

9. An aircraft comprising a propulsion system according to claim 8.

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