Turbomachine turbine assembly

Abstract

A turbine wheel assembly (48) is disclosed, having a longitudinal axis and comprising: - an exhaust casing (30), - a ejection cone (40) arranged downstream of the exhaust casing (30), the ejection cone (40) comprising an outer annular wall (42) for the flow of a primary air flow and a sound box (44) arranged radially inside the outer annular wall (42), the sound box (44) comprising a radially inner annular wall (46), - a connection part (50) longitudinally interposed between the exhaust casing (30) and the inner annular wall (46) of the ejection cone (40), the connection part (50) being fastened to the exhaust casing (30) and to the inner annular wall (46), wherein an upstream end of the outer annular wall (42) is connected to the connection part (50) with a degree of freedom in radial direction and with a degree of freedom in longitudinal direction.

Description

Technical Field

[0001] This disclosure relates to a turbine assembly. It also relates to a turbine including such an assembly, and to a turbine including such a turbine. Background Technology

[0002] Normally, such as Figure 1 As indicated, the turbofan turbine 10 includes, from upstream to downstream, a fan 12, a low-pressure compressor 14a, a high-pressure compressor 14b, a combustion chamber 16, a high-pressure turbine 18a, a low-pressure turbine 18b, and an exhaust nozzle 20 in the gas circulation direction within the turbine 10. The high-pressure compressor 14b and the low-pressure compressor 14a are connected to the high-pressure turbine 18a and the low-pressure turbine 18b, respectively, via corresponding shafts extending in the longitudinal direction X according to the rotation of the turbine shaft. Next, directional qualifiers such as "longitudinal," "radial," and "circumferential" are defined with reference to the longitudinal axis X.

[0003] The airflow entering the turbine is split downstream of fan 12 into an annular primary airflow entering a so-called primary annular flow path 22a and an annular secondary airflow entering a so-called secondary annular flow path 22b surrounding the primary annular flow path 22a. The low-pressure compressor 14a and high-pressure compressor 14b, combustion chamber 16, and high-pressure turbines 18a and low-pressure turbines 18b are located within the primary annular flow path 22a for their respective working components.

[0004] The exhaust sleeve 30 is located directly at the outlet of the low-pressure turbine 18b. The exhaust sleeve 30 includes a radial inner shroud 32 and a radial outer shroud 34. The annular space formed between the inner shroud 32 and the outer shroud 34 forms part of a primary annular flow path 22a at the outlet of the low-pressure turbine 14b.

[0005] The exhaust nozzle 20 of the turbine 10, or the exhaust nozzle in general, includes an assembly that allows for the optimization of hot gases originating from the turbine. This assembly may also have the function of absorbing at least a portion of the noise generated by the interaction of these hot gases with ambient air and cool airflow from the fan.

[0006] This assembly includes Figure 2 The jet cone 40, as shown herein, includes an upstream portion 40a having a substantially cylindrical shape and a downstream portion 40b having a conical shape. The upstream portion 40a is formed by a radially outer annular wall 42 and a acoustic chamber 44 radially arranged inside the outer annular wall 42. The acoustic chamber 44 includes a radially inner annular wall 46. The radially outer surfaces of the outer annular wall 42 of the upstream portion 40a and the radially outer surfaces of the conical downstream portion 40b define a primary annular flow path 22a radially inward at the jet cone 40.

[0007] The injection cone 40 is connected upstream to the exhaust sleeve 30 via a connecting member 50 inserted longitudinally between the exhaust sleeve 30 and the injection cone 40. The upstream end of the injection cone 40 is connected to the inner shroud 32 of the exhaust sleeve 30.

[0008] Due to the significant temperature gradient applied between the inner annular wall 42 and the outer annular wall 46, it is known to mechanically separate the outer annular wall 42 from the inner annular wall 46 upstream. This has the effect of limiting the thermomechanical stress applied to the outer annular wall 42. For this purpose, the inner annular wall 46 is firmly connected to the connecting member 50, while the upstream end of the outer annular wall 42 is free to allow free expansion of the outer annular wall 42 relative to the inner annular wall 46. Therefore, the upstream portion of the outer annular wall 42 is arranged radially opposite the radially outer surface of the connecting member 50.

[0009] However, this arrangement has the disadvantage of creating a radial gap between the radially outer surface of the connecting member 50 and the upstream portion of the outer annular wall 42. This radial gap induces recirculation of hot air from the low-pressure turbine 14b towards the interior of the acoustic chamber (i.e., between the inner annular wall 42 and the outer annular wall 46) at the junction between the exhaust sleeve 30 and the injection cone 40, which reduces the efficiency of the turbine and may reduce the efficiency of the acoustic chamber 44. Summary of the Invention

[0010] A turbine assembly with a longitudinal axis is provided, comprising:

[0011] -Exhaust sleeve,

[0012] - A jet cone, arranged downstream of an exhaust sleeve, the jet cone comprising an outer annular wall for the flow of a primary airflow and a acoustic chamber radially arranged within the outer annular wall, the acoustic chamber comprising a radially inner annular wall.

[0013] A connecting component, which is longitudinally inserted between the exhaust sleeve and the inner annular wall of the injection cone, is fastened to both the exhaust sleeve and the inner annular wall.

[0014] The upstream end of the outer annular wall is connected to the connecting component with degrees of freedom in the radial and longitudinal directions.

[0015] This technical solution allows for the reduction of thermomechanical stress in the outer annular wall of the cone and the inner annular wall of the box, because the thermal expansion of each of these two walls can occur independently.

[0016] Due to the use of flexible connections with degrees of freedom in both the radial and longitudinal directions, the installation according to this document allows for satisfactory aerodynamic stability of the primary airflow path. Therefore, at the junction between the outer annular wall and the connecting components, the circulation of primary airflow towards the space within the soundbox located between the outer and inner annular walls is restricted, or even blocked.

[0017] A specific annular sealing member can be provided between the connecting component and the upstream end of the outer annular wall.

[0018] The downstream end of the outer annular wall of the cone and the downstream end of the downstream annular wall of the sleeve can be rigidly fastened to each other, due to the different thermal expansion between the two walls caused by the installation according to the invention performed upstream.

[0019] The connecting component may include an outer annular wall, which at its downstream end comprises a connecting member that is elastically deformable in the radial and longitudinal directions.

[0020] The outer annular wall of the connecting component may include a plurality of circumferential tabs, each tab having a first circumferential end connected to the outer annular wall of the connecting component and an opposing second circumferential end that is freely and rigidly fastened to the upstream end of the outer annular wall of the injection cone.

[0021] Compared to longitudinal tabs, the use of circumferential tabs allows for good flexibility in the tabs while having a reduced longitudinal volume.

[0022] Each tab's free end can be convex and fit into a concave groove with an outer annular wall of a connecting component.

[0023] The upstream end of the outer annular wall of the cone can be applied radially to the outer radial surface of the connecting component. In this way, the tab is covered by the upstream end of the outer annular wall of the cone, which allows for the reconstruction of a substantially continuous surface of more than 360°, thereby limiting interference with the primary airflow.

[0024] The connecting components may include a plurality of elastically deformable lugs, which are circumferentially spaced apart from each other and rigidly fastened, for example by bolts, to the upstream end of the inner annular wall of the sound box.

[0025] The connecting components may include a first annular portion and a second annular portion that are structurally different from each other and fastened to the exhaust sleeve. The first annular portion is the portion that allows the upstream end of the outer annular wall to be connected to the connecting component with degrees of freedom in the radial and longitudinal directions. The second annular portion is connected to the upstream end of the inner annular wall of the sound box.

[0026] Each of the inner and outer annular walls can be made of a ceramic matrix composite material. This material has a low density, thus enabling a reduction in the mass of the jet cone. The composite material used can be carbide-based or oxide-based, with long or short fibers.

[0027] According to another aspect, a turbine is described, which includes a turbine assembly as previously described.

[0028] According to another aspect, a turbine is described, which includes a turbine as previously described. Attached Figure Description

[0029] Other features, details, and advantages will be presented when reading the detailed description below and when analyzing the accompanying drawings, wherein:

[0030] [ Figure 1 This is a partial schematic half-view of the axial section of a prior art turbine;

[0031] [ Figure 2 ]for Figure 1 A schematic diagram of a larger proportion of the area defined by dotted lines;

[0032] [ Figure 3 [This is a schematic diagram of an embodiment according to this document.] Detailed Implementation

[0033] For reference Figure 3 This refers to the turbine assembly 48 according to an embodiment of this specification. (See reference...) Figure 1 The turbine assembly described, which has a longitudinal axis, can be implemented in a turbine.

[0034] The assembly further includes an injection cone 40. The injection cone 40 is arranged downstream of the exhaust sleeve 30. Figure 3 (Not shown in the image). The jet cone 40 includes an upstream portion 40a, which includes an outer annular wall 42 for the flow of a primary airflow. The jet cone further includes a sound chamber 44 radially disposed within the outer annular wall 42, the sound chamber 44 including a radially inner annular wall 46. The sound chamber may include multiple sections extending between the inner and outer annular walls to form a honeycomb structure. The outer annular wall 42 may include perforations that allow sound waves to enter the interior of the sound chamber 44.

[0035] Each of the inner annular wall 42 and the outer annular wall 46 may be made of a ceramic matrix composite material. This material has a low density, thus enabling a reduction in the mass of the injection cone 40. The composite material used may be carbide-based or oxide-based, with long or short fibers.

[0036] The assembly also includes a connecting member 50 that is longitudinally inserted between the exhaust sleeve 30 (not shown) and the inner annular wall 46 of the injection cone 40. The connecting member 50 is fastened to the exhaust sleeve 30 on one hand and to the inner annular wall 46 on the other.

[0037] For this purpose, the connecting member 50 includes a radial annular flange 52 fastened to the inner shroud 32 of the exhaust sleeve 30. In particular, the radial annular flange 52 is screwed onto the inner shroud 32 and is located on an annular flange that is longitudinally opposite to the exhaust sleeve.

[0038] The radially inner end of the radial annular flange 52 is connected to a plurality of elastically deformable lugs 54, which are circumferentially spaced from each other and rigidly fastened, for example by bolts, to the upstream end of the inner annular wall 46 of the sound box 44. Figure 3 The diagram is shown schematically.

[0039] like Figure 3 As shown, the connecting member 50 includes a first annular portion 50a and a second annular portion 50b. The second annular portion 50b is formed by a radial annular flange 52 for fastening to the exhaust sleeve 30 and is formed by a flexible lug 54. The first annular portion 50a includes an upstream annular flange 56 of the radial annular flange 52 that is fastened to the second annular portion 50b, for example, by bolting.

[0040] The radial annular flange 56 of the first annular portion 50a is connected to an outer annular wall 58 arranged radially opposite to the flexible lug 54 of the second annular portion 50b.

[0041] The downstream portion of the outer annular wall 58 of the first part 50a includes a member that is elastically deformable in both the radial and longitudinal directions. Figure 3 In the specific example illustrated, these components include circumferential tabs 60. Each tab 60 includes a first circumferential end 60a connected to the outer annular wall 58 of the connecting member 50 and an opposing second circumferential end 60b that is free and rigidly fastened to the upstream end of the outer annular wall 42 of the jet cone 40.

[0042] The downstream edges of the circumferential tabs 60 are circumferentially aligned. Each tab 60 includes a circumferentially elongated body 60c, which defines a slot 69 with an outer annular wall 58 capable of deforming the tab 60. A second circumferential end 60b has a convex peripheral shape and fits into a corresponding concave groove in the outer annular wall 58 of the first portion 50a of the connecting member 50. The second end 60b of each circumferential tab 60 includes an aperture 62 intended for a screw to pass through for fastening at the upstream end of the outer annular wall 42 of the cone 40. The upstream end of the outer annular wall 42 of the cone 40 is radially applied herein to the outer radial surface of the outer annular wall 58 of the first annular portion 50a of the connecting member 50.

[0043] According to the proposed configuration, the upstream end of the outer annular wall 42 is thus connected to the connecting member 50 with degrees of freedom in the radial direction and in the longitudinal direction.

[0044] The previously described assembly separates the outer annular wall 42 of the cone 40 and the inner annular wall 46 of the soundbox 44, so that these two walls are no longer fastened to each other. This allows for different expansions between the two walls in the radial and longitudinal directions, thereby allowing for reduced thermomechanical stress during the application of a radial thermal gradient to the assembly 48 according to this document. Furthermore, the partial sealing and resistance of the outer annular wall 42 of the cone 40 under mechanical load ensures aerodynamic stability of the engagement between the connecting member 50 and the outer annular wall 42 of the cone 40.

Claims

1. A turbine assembly (48) having a longitudinal axis, comprising: -Exhaust sleeve (30). - A jet cone (40) is arranged downstream of the exhaust sleeve (30), the jet cone (40) including an outer annular wall (42) for the flow of a primary airflow and a sound box (44) arranged radially inside the outer annular wall (42), the sound box (44) including a radially inner annular wall (46). - A connecting component (50) is longitudinally inserted between the exhaust sleeve (30) and the inner annular wall (46) of the injection cone (40). The connecting component (50) includes a first annular portion (50a) and a second annular portion (50b), which are fastened to each other and to the exhaust sleeve (30). The second annular portion (50b) is connected to the upstream end of the inner annular wall (46), wherein the upstream end of the outer annular wall (42) is connected to the first annular portion (50a) of the connecting component (50) with degrees of freedom in the radial direction and in the longitudinal direction.

2. The assembly (48) according to claim 1, characterized in that, The connecting component (50) includes an outer annular wall (58) which is contained at its downstream end as a connecting member that is elastically deformable in the radial direction and in the longitudinal direction.

3. The assembly according to claim 2, characterized in that, The outer annular wall (58) of the connecting member (50) includes a plurality of circumferential tabs (60), each tab (60) having a first circumferential end (60a) connected to the outer annular wall (58) of the connecting member (50) and an opposing second circumferential end (60b) freely and rigidly fastened to the upstream end of the outer annular wall (42) of the jet cone (40).

4. The assembly according to claim 3, characterized in that, Each tab (60) has a convex free end and is fitted into a concave groove in the outer annular wall (42) of the connecting member (50).

5. The assembly according to any one of claims 1 to 4, characterized in that, The connecting component (50) includes a plurality of elastically deformable lugs (54) that are circumferentially spaced apart from each other and rigidly fastened by bolts to the upstream end of the inner annular wall (46) of the sound box (44).

6. The assembly according to any one of claims 1 to 4, characterized in that, The upstream end of the outer annular wall (42) of the cone (40) is radially applied to the outer radial surface of the connecting member (50).

7. A turbine comprising a turbine assembly according to any one of the preceding claims.

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