Aircraft propulsion system

Abstract

The invention relates to a propulsion assembly (1) for an aircraft comprising a turbomachine (2), a fixed internal fairing (4) which surrounds the turbomachine (2) and which includes a support structure (40) which supports the turbomachine (2), an external fairing (5) which circumferentially surrounds the internal fairing (4) and which includes a first (11A) and a second (11B) internal wall, a first cowling (10A) which includes a first external wall (12A) which surrounds the first internal wall (11A) and which defines with it a first annular rib (V1A), and a second cowling (10B) which includes a second external wall (12B) which surrounds the second internal wall (11B) and which defines with it a second annular rib (V1B), the cowlings (10A, 10B) being able to pass between a closed position and an open position. The first hood (10A) (respectively the second hood (10B)) comprises the first inner wall (11A) (respectively the second inner wall (11B)). Figure 2A

Description

Title of the invention: Aircraft propulsion system

[0001] The present invention relates to the field of aircraft propulsion assemblies, in which the propulsion assembly comprises or is intended to comprise a turbomachine, a nacelle intended to surround the turbomachine and a mast or pylon intended to connect the turbomachine to the aircraft.

[0002] The propulsion unit and the turbomachine extend along a longitudinal axis X is the axis of rotation of the turbomachine and corresponds to the direction of air and gas flow during normal operation of the propulsion system. Upstream and downstream are defined relative to this air and gas flow direction. The turbomachine includes a gas generator, and the nacelle comprises an internal fairing and an external fairing that radially surrounds this internal fairing.

[0003] The internal fairing comprises a support structure that circumferentially surrounds and supports the turbomachine. The external fairing comprises two C-shaped cowlings on either side of a first V-shaped plane that divides the turbomachine in two longitudinally and includes the longitudinal axis X. Each cowling has a radially external circumferential wall. When the turbomachine is mounted under the aircraft wing, the first V-shaped plane is vertical and therefore passes through the middle of the pylon. Alternatively, the turbomachine can be mounted laterally on the aircraft fuselage. The external fairing also comprises two internal walls, each surrounding half a circumference of the turbomachine and the support structure on either side of the first V-shaped plane.An annular space is defined radially inward by these inner walls and radially outward by the radially outer walls of the cowlings. In the closed position, each cowling surrounds half a circumference of the turbomachine. In the open position, each cowling rises radially outward to allow maintenance of the turbomachine. Each cowling is hinged at its upper end to one side of the pylon by a linkage, for example, a pivot joint, which allows passage between its closed and open positions. The open position allows maintenance of the components located under the cowlings.

[0004] Thus, the present invention relates to an aircraft propulsion assembly extending around a longitudinal axis X which corresponds to the direction of gas flow during normal operation of this propulsion assembly and which defines an upstream and a downstream section. This propulsion assembly comprises a fixed internal fairing intended to surround a turbomachine and includes a support structure for supporting the turbomachine, and an external fairing which circumferentially surrounds the internal fairing and includes a first internal wall and a second internal wall which extend from upstream to downstream along the longitudinal axis X relative to a first plane V passing through the longitudinal axis X, the external fairing also comprising a first hood which includes a first external wall which surrounds the first internal wall and which defines with this first internal wall a first annular vein and also comprising a second hood which includes a second external wall which surrounds the second internal wall and which defines with this second internal wall a second annular vein, the hoods extending from upstream to downstream along the longitudinal axis X relative to the first plane V and being able to pass between a closed position and an open position.

[0005] Figure 4A illustrates such a propulsion assembly in cross-section in a transverse plane (perpendicular to the longitudinal axis X). For clarity, the turbomachine is not shown. The first internal wall 120A and the second internal wall 120B extend symmetrically from upstream to downstream along the longitudinal axis X relative to the first vertical plane V passing through the longitudinal axis X. The internal walls (120A, 120B) are integral with a fixed (removable) circumferential support structure 140, which is connected to the engine and forms part of the internal fairing 4. The internal walls (120A, 120B) thus contribute to the engine's suspension and act as load transfer devices. The support structure 140 includes in particular an upper bifurcation 141 (at 12 o'clock) located above the turbomachine and a lower bifurcation 142 located below (at 6 o'clock) the turbomachine.Each internal wall (120A, 120B) forms essentially a half-cylinder that extends circumferentially along the support structure 140 from the upper bifurcation 141 to the lower bifurcation 142. The first cover 110A has a first external wall 112A that surrounds the first internal wall 120A. The second cover 110B has a second external wall 112B that surrounds the second internal wall 120B. In Figure 4A, the covers (110A, 110B) are shown in the closed position.

[0006] In Figure 4B, the second cover 110B is shown in the open position, after pivoting radially outwards around its end which joins the upper bifurcation 141. During the transition from the closed to the open position, the second cover 110B, with its second outer wall 112B, moves away from the second inner wall 120B, which remains stationary as it is integral with the fixed support structure 140. The opening of the first cover 110A occurs in a similar and symmetrical manner to the opening of the second cover 110B.

[0007] Figure 5 is a partial longitudinal cross-sectional view of a portion of the propulsion assembly with the cowlings (110A, 110B) in the closed position. The section is taken at the level of the first cowling 110A. The situation is identical for the second cowling 110B, replacing the references "A" with "B" and the adjectives "first / "First" by "Second." The cross-section illustrates three portions of the propulsion assembly from upstream to downstream. The support structure 140 is fixed upstream to a motor structure 150 and downstream to a suspension structure 160. The first inner wall 120A is integral with the support structure 140. The first cowling 110A has a first outer wall 112A which rests (at the level of a first support zone 170A) on radial struts 113 which are fixed to the first inner wall 120A and extend radially outwards. These masts 113 are distributed circumferentially on the first inner wall 120A and are visible in figures 4A, 4B and 5. When the first hood 110A moves from its closed position to its open position, the masts 113 therefore remain fixed and the first outer wall 112A moves away from the masts 113.

[0008] Each of the inner walls (120A, 120B) defines, together with the outer wall (112A, 112B) of the surrounding cowl (110A, 110B), an annular channel (WIA, WIB) in which air flows from upstream to downstream during normal operation of the turbomachine. For the first cowl 110A (respectively, the second cowl 110B), the first annular channel W1A (respectively, the second annular channel W1B) thus extends approximately over half a circumference. These annular channels (W1A, W1B) are visible in Figures 4A, 4B, and 5. In [Fig. 5], arrow F indicates the direction of airflow from upstream to downstream (from left to right in the figure) in the annular channel W1A.

[0009] As mentioned above, the internal walls (120A, 120B) are integral with the fixed engine support structure 140 in order to serve as a load path for the engine suspension. A consequence of this is that each of the annular ribs (W1A, W1B) is formed by two separate walls, namely an internal wall (120A, 120B) and the external wall (112A, 112B) of the cowling (110A, 110B) that surrounds it. This results in difficulty in controlling and maintaining the geometry of the aerodynamic surfaces during operation, particularly under mechanical and thermal stresses. Description of the invention

[0010] The present invention aims to remedy these drawbacks.

[0011] The invention aims to provide a propulsion system for aircraft in which the annular veins surrounded by the external walls of the cowlings exhibit better stability.

[0012] This goal is achieved thanks to the fact that the first hood includes the first internal wall and the second hood includes the second internal wall.

[0013] Thanks to these arrangements, each of the annular veins is defined by a single unit, namely the internal and external walls which form part of the same hood. Consequently, better control is achieved over the geometry of the veins and the outlet cross-section of the airflow passing through them, while maintaining the function of The turbomachine is suspended by the support structure while retaining the hood opening function, which allows for turbomachine maintenance. Disassembly of the internal structure is also facilitated.

[0014] For example, each of the internal walls includes a panel which has a sound attenuation structure.

[0015] For example, each of these panels includes cells open on the annular vein.

[0016] For example, the cell walls are acoustically absorbent.

[0017] For example, the external fairing includes radial masts that connect the right inner wall and the right outer wall and radial masts that connect the left inner wall and the left outer wall.

[0018] For example, each of the hoods retains its outlet section during its transition between its closed position and its open position

[0019] For example, each of said hoods, in its passage between its closed position and its open position, pivots by means of a pivot joint at one of its ends relative to a fixed structure.

[0020] 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:

[0021] [Fig-1] Fig. 1 is a perspective view from the rear of the propulsion assembly according to the invention.

[0022] [Fig.2] Fig.2 is: In (A) a cross-sectional view of the propulsion assembly according to the invention seen from the front with both hoods closed; In (B) a cross-sectional view of the propulsion assembly seen from the front with the left hood open.

[0023] [Fig.3] The [Fig.3] is a partial longitudinal cross-sectional view of the propulsion assembly according to the invention with the two hoods closed along line 111-111 of the [Fig.2](A).

[0024] [Fig.4] The [Fig.4], already described, is: In (A) a cross-sectional view of the propulsion assembly according to the prior art seen from the front with both hoods closed; In (B) a cross-sectional view of the propulsion assembly seen from the front with the left hood open.

[0025] [Fig.5] The [Fig.5], already described, is a partial longitudinal cross-sectional view of the propulsion assembly according to the prior art with both hoods closed. Detailed description of the invention

[0026] Consider a propulsion system 1 for an aircraft extending along a longitudinal axis X which corresponds to the direction of gas flow during operation The normal orientation of this propulsion assembly defines an upstream (front) and a downstream (rear) side, as well as a first and second side, when 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" following a part number designates that part on the first right side, and the letter "B" following a part number designates that part on the second left side. The adjective "transverse" describes an element perpendicular to the longitudinal axis X.

[0027] Such a propulsion assembly 1, shown in [Fig. 1] in perspective from the rear, comprises a turbomachine 2 (shown in fine dashed lines), a connecting element 3 (for example, a pylon) that connects the turbomachine 2 to the wing of the aircraft, an inner fairing 4 that surrounds the turbomachine 2, and an outer fairing 5 that circumferentially surrounds the inner fairing 4. The longitudinal axis X is the axis of rotation of the turbomachine 2. Alternatively, the propulsion assembly 1 is intended to include this turbomachine 2. A portion of the inner fairing 4 is shown in dashed lines in [Fig. 1] because the inner fairing 4 is hidden by the outer fairing 5. The outer fairing 5 comprises a first C-shaped cowling 10A and a second C-shaped cowling 10B that extend, for example, symmetrically, from upstream to downstream. along the longitudinal axis X with respect to a first plane V passing through the longitudinal axis X.A first axis Z is defined, extending in the first plane V, perpendicular to the longitudinal axis X, and passing through the upstream part of pylon 3 and the cowlings (10A, 10B). In the description below, pylon 3 is located above propulsion unit 1. The first plane V is therefore vertical. The cowlings (10A, 10B) are located below pylon 3. The first cowling 10A is the right cowling and the second cowling 10B is the left cowling.

[0028] However, the invention also covers the case where the propulsion assembly 1 is mounted laterally on the fuselage, in which case the pylon is lateral to the cowlings (10A, 10B), and the first wing V is horizontal. The description below is therefore valid for this case, replacing the adjectives as necessary. In particular, "right" is replaced by "first" and "left" by "second", "upper" by "proximal", and "lower" by "distal".

[0029] The hoods (10A, 10B) are capable of moving between a closed and an open position. In the closed position, as shown in [Fig. 1], each of the hoods (10A, 10B) forms half of a substantially circular annular shell whose axis is the longitudinal axis X, extending from a proximal (upper) end closest to the pylon 3 around the internal fairing 4 to the vertical plane V. Thus, the distal (lower) end of the right-hand hood 10A joins the distal (lower) end The left cowling 10B is located at the level of the vertical plane V. In the open position, each of the cowlings (10A, 10B) rises radially outwards to allow access to the internal fairing 4 and the turbomachine 2. The right cowling 10A (respectively left cowling 10B) is hinged at its proximal end to the pylon 3 by a right-hand hinge 90A (respectively left-hand hinge 90B) which allows, by pivoting, the transition between its closed and open positions. The right-hand hinge 90A is hidden by the pylon 3 in [Fig. 1]. These joints (90A, 90B) are direct pivot links between the hoods (10A, 10B) and pylon 3. Alternatively, these joints (90A, 90B) are pivot links between the hoods (10A, 10B) and a fixed structure, which for example is connected to pylon 3.

[0030] Figure 2A illustrates a propulsion assembly in cross-section in a transverse plane (perpendicular to the longitudinal axis X). For clarity, the turbomachine is not shown. In Figure 2A, the cowlings (10A, 10B) are shown in the closed position.

[0031] The external fairing 5 comprises a right-hand internal wall 1 IA and a left-hand internal wall 1 IB extending upstream to downstream along the longitudinal axis X over a certain length. The right-hand internal wall 11A (respectively, left-hand internal wall 1 IB) extends from an upstream edge 115A (respectively, 115B) to a downstream edge 116A (respectively, 116B). The right-hand internal wall 1 IA and the left-hand internal wall 1 IB extend, for example, symmetrically, with respect to the vertical plane V passing through the longitudinal axis X. The right-hand internal wall 1 IA forms part of the right-hand cowling 10A. The left-hand internal wall 1 IB forms part of the left-hand cowling 10B. The right hood 10A has a right external wall 12A which is located radially outside the right internal wall 11A such that the right external wall 12A defines with the right internal wall 11A a right annular vein VI A. The right internal wall 11A and the right external wall 12A are solid.The left flap 10B has a left external wall 12B which is located radially outside the left internal wall 1 IB such that the left external wall 12B, together with the left internal wall 1 IB, defines a left annular vein V1B. The left internal wall 1 IB and the left external wall 12B are integral. Thus, each of the annular veins (VIA, V1B) is defined by a single, continuous structure.

[0032] For example, the right internal wall 11A (respectively left internal wall 1 IB) includes an aerodynamic panel 14A (respectively 14B), which allows for improved airflow in each of the annular ducts (VIA, V1B). Optionally, each of these panels (14A, 14B) has a sound-attenuating structure, which allows for improved sound insulation of the turbomachine 2. Thus, each of these panels (14A, 14B) includes, for example, cells open onto the annular duct (VIA, V1B), these cells constituting this sound-attenuating structure. Advantageously, the walls of these cells are Acoustically absorbent, meaning they have reliefs that help to attenuate sound through absorption and multiple reflections. These reliefs can be cones or pyramids. Advantageously, each of these cells is closed at the end opposite its opening. For example, panel 14A of the right-hand internal wall 1IA extends from its upstream edge 115A to its downstream edge 116A, and similarly, panel 14B of the left-hand internal wall 1IB extends from its upstream edge 115B to its downstream edge 116B, as illustrated in [Fig. 3] described below.

[0033] The external fairing 5 includes radial struts 13 that connect the right inner wall 1 IA and the right outer wall 12A. These struts 13 are distributed circumferentially on the right inner wall 11 A. The external fairing 5 includes other radial struts 13 that connect the left inner wall 1 IB and the left outer wall 12B. These struts 13 are distributed circumferentially on the left inner wall 11B. These struts 13 contribute to securing the right inner wall 11A (respectively left inner wall 1 IB) and the right outer wall 12A (respectively left outer wall 12B). All these struts 13 are visible in Figure 2A as well as in Figure 2B and in [Fig. 3] described below.

[0034] The internal fairing 4 comprises a fixed (removable) circumferential support structure 40 (with respect to the longitudinal axis X) that supports and surrounds the turbomachine 2. The support structure 40 is connected to the pylon 3. The support structure 40 thus acts as a load-bearing structure. The support structure 40 includes, in particular, an upper bifurcation 41 (at 12 o'clock) located above the turbomachine 2 and a lower bifurcation 42 located below (at 6 o'clock) the turbomachine 2. Thus, the support structure 40 has the shape of a circular shell that includes the upper bifurcation 41 and the lower bifurcation 42. For example, the upper bifurcation 41 is connected to the pylon 3.

[0035] For example, the support structure 40 includes an openwork portion. This openwork portion extends between the upper bifurcation 41 and the lower bifurcation 42.

[0036] Figure 3 is a partial longitudinal cross-sectional view of a portion of the propulsion assembly with the cowlings (10A, 10B) in the closed position as illustrated in Figure 2(A). The section is taken at the right cowling 10A, the situation being identical for the left cowling 10B. The section illustrates three portions of the propulsion assembly from upstream to downstream. Arrow F indicates the direction of airflow from upstream to downstream (from left to right in the figure) in the right annular channel VIA. The support structure 40 is fixed upstream to a drive structure 50 and downstream to a suspension structure 60. In the closed position, each of the internal walls (1 IA, 1 IB) rests on the assembly formed by the support structure 40, the drive structure 50, and the suspension structure 60, as illustrated in Figure 3. This support is provided for the right internal wall 1 IA (respectively left 1 IB) on a right support zone 70A (respectively left 70B). For example, this support area (70A, 70B) consists, upstream of this internal wall (1IA, 1IB), of a portion of the drive structure 50 and, downstream of this internal wall (1IA, 1IB), of a portion of the support structure 40 adjacent to the suspension structure 60. Alternatively, downstream of this internal wall (1IA, 1IB), the support area (70A, 70B) includes a portion of the suspension structure 60. This support consists of simple contact. In contrast, in prior art embodiments, such as those illustrated in Figures 4 and 5, the internal walls (120A, 120B) of the hoods (110A, 110B) are permanently attached to the support structure 140.

[0037] In certain embodiments according to the invention, each of the internal walls (1 IA, 1 IB) can also be removably fixed to the assembly formed by the support structure 40, the motor structure 50 and the suspension structure 60.

[0038] In Figure 2B, the left cover 10B is shown in the open position, after pivoting radially outwards around its end located at the upper bifurcation 41. The opening of the right cover 10A is similar and symmetrical. When the cover (10A, 10B) pivots between the closed and open positions, the inner wall (1 IA, 1 IB) and the outer wall (12A, 12B) pivot as a single unit. Thus, the inner wall (1 IA, 1 IB) moves radially away from the support structure 40 except at its end where it joins the upper bifurcation 4L. The cover (10A, 10B) maintains its geometry and shape during the transition of the cover (10A, 10B) between its closed and open positions.The dimensional stability of the annular vein (IVA, V1B) is thus improved compared to the anterior art situation where the external wall (12A, 12B) is dissociated from the internal wall (1IA, 1IB) during flap rotation (10A, 10B). The exit cross-section (i.e., its height or dimension measured perpendicular to the internal walls (11A, 1IB)) of the right annular vein (IVA, V1B) is maintained between the closed and open positions. In other words, the right annular vein (IVA, V1B) has a first exit cross-section in the closed position and a second exit cross-section in the open position, and these first and second exit cross-sections are identical. This outlet section is defined at the downstream end 126A of the right external wall 12A (respectively downstream end 126B of the left external wall 12B), referenced in [Fig.3].The outlet section is represented by the double arrow S. The outlet section of the right annular vein VIA (respectively left V1B) is also called the outlet section of the right hood 10A (respectively left 10B).

Claims

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5. Demands Propulsion assembly (1) for an aircraft extending around a longitudinal axis (X) which corresponds to the direction of gas flow in normal operation of this propulsion assembly and which defines an upstream and a downstream, said propulsion assembly (1) comprising a fixed internal fairing (4) intended to surround a turbomachine (2) and which includes a support structure (40) intended to support said turbomachine (2), an external fairing (5) which circumferentially surrounds said internal fairing (4) and which includes a first internal wall (1 IA) and a second internal wall (1 IB) which extend from upstream to downstream along said longitudinal axis (X) relative to a first plane (V) passing through the longitudinal axis (X), said external fairing (5) also comprising a first cowling (10A) which includes a first external wall (12A) which surrounds said first internal wall (1 IA) and which, together with said first internal wall (11 A), defines a first annular duct (VIA),and also comprising a second hood (10B) which includes a second outer wall (12B) surrounding said second inner wall (11B) and which, together with said second inner wall (11B), defines a second annular vein (V1B), said hoods (10A, 10B) extending from upstream to downstream along said longitudinal axis (X) relative to said first plane (V) and being capable of passing between a closed position and an open position, said propulsion assembly (1) being characterized in that said first hood (10A) comprises said first inner wall (11A) and said second hood (10B) comprises said second inner wall (11B). Propulsive assembly (1) according to claim 1 such that each of said internal walls (11A, 11B) comprises a panel (14A, 14B) which has an acoustic attenuation structure. Propulsive assembly (1) according to claim 2 such that each of said panels (14A, 14B) comprises cells open on said annular vein (VIA, V1B). Propulsive assembly (1) according to claim 3 such that the walls of said cells are acoustically absorbent. Propulsion assembly (1) according to any one of claims 1 to 4, wherein said external fairing (5) comprises radial struts (13) which connect said right inner wall (11 A) and the outer wall right (12A) and radial masts (13) which connect said left inner wall (1 IB) and left outer wall (12B).

6. Propulsion assembly (1) according to any one of claims 1 to 5 such that each of said hoods (10A, 10B) retains its exit section during its passage between its closed position and its open position.

7. Propulsion assembly (1) according to any one of claims 1 to 6 such that each of said hoods (10A, 10B), in its passage between its closed position and its open position, pivots by means of a pivot joint at one of its ends relative to a fixed structure.

8. Propulsion assembly (1) according to any one of claims 1 to 7 further comprising said turbomachine (2).

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