Seal assembly for a turbo-injector cone

Abstract

The invention relates to an assembly for a turbine of a turbomachine, said assembly extending along an axis (X), comprising: - an ejection cone (100) comprising a radially outer annular wall (102) delimiting a flow duct for a flow of hot gases and an acoustic box arranged radially inside said outer annular wall (102), said acoustic box comprising a radially inner annular wall (104), - a connecting part (106) intended to be inserted axially between an exhaust casing and said ejection cone (100), said connecting part (106) comprising an upstream annular flange (108) intended to be attached to said exhaust casing and a plurality of downstream fixing tabs (110) connected to said inner annular wall (104), - an annular sealing shroud (112) comprising an upstream portion surrounding said fixing tabs (110) of said connecting part (106) so as to cover the space located circumferentially between said fixing tabs (110) and axially between said upstream annular flange (108) of said connecting part (106) and said radially inner annular wall (104).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an assembly for a turbine of a turbomachine, such as a turbojet or turboprop engine of an aircraft. BACKGROUND

[0002] Turbomachines of the bypass turbojet engine type conventionally comprise, in the direction of circulation of the gases within the turbomachine, from upstream to downstream: a fan, a low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, a low-pressure turbine and an exhaust nozzle.

[0003] The air flow entering the turbomachine is divided downstream of the fan into a primary flow which enters a so-called primary duct and a secondary flow which enters a so-called secondary duct. The low-pressure compressor and the high-pressure compressor, the combustion chamber, and the high-pressure turbine and the low-pressure turbine are located in the primary duct.

[0004] The high-pressure turbine is connected to the high-pressure compressor via a high-pressure shaft. The low-pressure turbine is connected to the low-pressure compressor and to the fan via a low-pressure shaft and possibly via a gear reducer.

[0005] The exhaust nozzle or ejection nozzle of a turbojet engine conventionally comprises an assembly which allows the hot gas flow originating from the turbine to be optimized. This assembly can also have the function of absorbing at least part of the noise generated by the interaction of these hot gases with the ambient air and with the cold air flow originating from the fan.

[0006] Figure 1 A portion of this assembly according to the prior art is illustrated in Figure 1.

[0007] The assembly extends along an axis X. The terms axial, radial and circumferential are defined with reference to the axis X. Furthermore, the terms upstream and downstream are defined with respect to the direction of circulation of the gases within the turbomachine.

[0008] This assembly comprises an ejection cone 10 which comprises an upstream portion 10a having a substantially cylindrical shape and a downstream portion 10b having a conical shape. The upstream portion 10a is formed by a radially outer annular wall 12 comprising a plurality of angular sectors connected together. The radially outer annular wall 12 and the radially outer surface of the conical downstream portion 10b delimit a portion of the aerodynamic duct for the circulation of the hot gases.

[0009] The upstream portion 10a comprises an acoustic box radially positioned inside with respect to the outer annular wall 12. The acoustic box is intended to reduce the noise pollution of the exhaust gases and comprises an inner annular wall 14 and a plurality of acoustic partitions 16 arranged radially between the inner annular wall 14 and the outer annular wall 12.

[0010] The assembly also comprises an exhaust casing. The upstream end of the injection cone 10 is connected to the exhaust casing. In particular, the inner annular wall 14 and the outer annular wall 12 of the injection cone 10 are connected to the exhaust casing by a connecting flange 18.

[0011] The connecting flange 18 comprises an upstream annular portion 17 and fixing tabs 19 extending axially downstream from the upstream annular portion 17. The fixing tabs 19 are uniformly distributed on the circumference and spaced apart from each other along the circumference. The connecting flange 18 is connected to the exhaust casing and the fixing tabs 19 are attached to the inner annular wall 14 of the injection cone 10.

[0012] In operation, hot gases originating from the main duct can penetrate into the inner volume of the downstream portion 10b of the injection cone 10 through the circumferential spaces 21 between the fixing tabs 19. This creates a risk of deterioration of this downstream portion 10b and of a decrease in the performance of the turbine.

[0013] The present invention aims to overcome these drawbacks in a simple, reliable and inexpensive manner. SUMMARY

[0014] To this end, the present invention relates to an assembly for a turbine wheel of a turbine, the assembly extending along an axis, comprising:

[0015] - an injection cone comprising a radially outer annular wall delimiting a hot gas flow duct and an acoustic box arranged radially inside said outer annular wall, said acoustic box comprising a radially inner annular wall,

[0016] - a connecting part intended to be axially interposed between an exhaust casing and said injection cone, said connecting part comprising an upstream annular flange intended to be attached to said exhaust casing and a plurality of downstream fixing tabs connected to said inner annular wall,

[0017] characterized in that the assembly comprises an annular sealing shroud comprising an upstream portion surrounding the fixing tabs of the connecting part so as to cover the spaces located circumferentially between said tabs and axially between the upstream annular flange of the connecting part and said radially inner wall.

[0018] Thus, the annular shroud allows covering the spaces into which the hot gas flow can penetrate. This reduces the penetration of the hot gas flow into the injection cone. Consequently, the performance of the turbine is improved.

[0019] In the present disclosure, upstream and downstream are defined with respect to the direction of circulation of the gases. The terms axial, radial and circumferential are defined with respect to the axis of the assembly, which coincides with the axis of the turbine. The inner annular wall is also referred to as the radially inner wall.

[0020] The sealing shield can be metallic. The sealing shield can be formed from one or more metal sheets. The sealing shield can be formed from multiple angular sectors joined together.

[0021] The sealing shield can have a radial thickness between 0.3 mm and 1 mm.

[0022] The downstream annular seal can be installed at the downstream end of the sealing cover and can be radially positioned relative to the radial inner wall.

[0023] Therefore, the downstream annular seal specifically allows filling any axial gap between the inner wall and the sealing shield during operation in order to limit the effects of differential thermal expansion during operation.

[0024] The downstream annular seal can be formed from a braided annular element. The braided element can be made of a textile material such as an aluminosilicate.

[0025] The downstream end of the sealing shield may include a groove that opens downstream, in which the downstream annular seal is mounted. The groove allows the downstream annular seal to be held in place.

[0026] The groove can have a C-shaped cross-section depending on the plane transverse to the axis of the assembly.

[0027] The groove may be located on the side of the radial outer surface of the annular main portion of the sealing shield.

[0028] The groove can be formed by the downstream end of the annular main portion of the cover and by a different component, which is attached to the downstream end of the annular main portion, for example, by welding. Alternatively, this attachment component can be made as a single piece with the annular main portion.

[0029] The sealing cover can be attached to the upstream annular flange of the connecting device.

[0030] Such attachments can be secured by screws, rivets, or any other suitable fastening components.

[0031] The upstream annular seal can be installed at the upstream end of the sealing shield and can be axially positioned relative to the outer annular wall of the injection cone.

[0032] The upstream annular seal can be formed from a braided annular element. The braided element can be made of, for example, aluminosilicate fabric.

[0033] Therefore, the upstream annular seal allows filling any annular gap located radially between the outer annular wall and the sealing shield.

[0034] The upstream end of the sealing shield may include a radially outwardly opening groove in which an upstream annular seal is mounted. The groove allows the upstream annular seal to be held in place.

[0035] The groove can have a C-shaped cross-section depending on the plane transverse to the axis of the assembly.

[0036] The groove may be located on the side of the radial outer surface of the annular main portion of the sealing shield.

[0037] The groove can be formed at least partially by a dissimilar component, which is attached to the upstream end of the annular main portion, for example, by welding. Alternatively, this attachment component can be made as a single piece with the annular main portion.

[0038] The damping component can be installed radially between the upstream end of the sealing cover and the outer annular wall.

[0039] The upstream annular seal can form the damping member.

[0040] The damping member can be formed by an elastically deformable tab extending radially from the sealing shield, the outer annular wall of which can be supported on the free end of the tab.

[0041] The damping member can be formed by an elastically deformable tab extending radially from the outer annular wall, and the sealing cover can be supported on the free end of the tab.

[0042] The tab can extend axially upstream or downstream. The tab can extend circumferentially around the axis of the assembly. The tab can deform in the radial direction.

[0043] The tabs can be evenly distributed on the circumference of the sealing shield.

[0044] The tab may be formed from a portion different from the rest of the sealing shield. In this case, the tab may be attached to the sealing shield by bolting, riveting, or brazing.

[0045] The tab can be made as a single piece with the rest of the sealing shield. The tab can be formed by cutting and bending a metal sheet that at least partially forms the sealing shield.

[0046] The retaining tabs of the connecting components can be rigid or flexible. Flexible retaining tabs allow for compensation of thermal expansion between the injection cone and the exhaust casing.

[0047] An acoustic enclosure may include multiple acoustic baffles extending radially outward from the inner annular wall of the acoustic enclosure. The acoustic baffles may be made of metal.

[0048] The inner or outer annular wall can be made of composite materials or metallic materials.

[0049] The jet cone may include a downstream portion made of a composite material having a ceramic matrix and connected to an outer annular wall. The downstream portion may be conical.

[0050] The exhaust casing can be made of metal.

[0051] The outer annular wall can form a surface continuity with a portion of the exhaust casing in order to define the flow channel for the hot gas flow.

[0052] The downstream portion of the inner annular wall can be attached to the downstream portion of the outer annular wall.

[0053] This disclosure also relates to turbines that include assemblies as previously mentioned. Attached Figure Description

[0054] [ Figure 1 [This is an exploded perspective view of a prior art jet cone.]

[0055] [ Figure 2 [This is a cross-sectional view of a portion of the assembly according to the first embodiment, wherein the downstream annular seal is shown in the cross-section.]

[0056] [ Figure 3 ] corresponds to Figure 2 The view shows the downstream annular seal in its annular form.

[0057] [ Figure 4 [This is a cross-sectional view of a portion of the assembly according to the second embodiment.]

[0058] [ Figure 5 [This is a cross-sectional view of a portion of the assembly according to the third embodiment.]

[0059] [ Figure 6 ]yes Figure 5 A perspective view of the sealing shield of the assembly. Detailed Implementation

[0060] Figure 2 and 3 This represents a portion of an assembly for a turbine with an axis X according to a first embodiment of the present invention. This assembly includes a jet cone 100, which on its upstream side includes an outer annular wall 102 defining a flow channel for a hot gas flow and an acoustic chamber radially disposed within the outer annular wall 102. The acoustic chamber includes an inner annular wall 104 radially disposed within the outer annular wall 102 and a plurality of acoustic baffles disposed between the outer annular wall 102 and the inner annular wall 104.

[0061] The assembly further includes an exhaust housing (not depicted). The inner annular wall 104 of the injection cone 100 is connected to the exhaust housing via a connecting flange 106.

[0062] The connecting flange 106 includes an upstream annular portion 108 and a retaining tab 110 extending axially downstream from the upstream annular portion 108. The retaining tabs 110 are evenly distributed on the circumference and spaced apart from each other along the circumference. The connecting flange 106 is connected to the exhaust housing, and the retaining tabs 110 are attached to the inner annular wall 104 of the injection cone 100, for example, by bolt connection.

[0063] The fixing tab 110 can be flexible or rigid.

[0064] The assembly further includes an annular sealing shield 112 arranged around the connecting flange 106 to cover the circumferential space between the fixing tabs 110 and the axial space between the annular portion 108 and the inner annular wall 104.

[0065] Therefore, the sealing shield 112 allows hot gas to be prevented from being introduced into the interior annular wall 104 through circumferentially positioned gaps or openings between the tabs 110.

[0066] The sealing cover 112 can be made of metal.

[0067] The upstream end of the sealing cover 112 can be attached to the annular portion 108 of the connecting flange 106.

[0068] The sealing shield 112 includes, for example, a cylindrical annular portion 114. The internal shape of the annular portion 114 matches the external shape of the annular portion 108 of the connecting flange 106.

[0069] The downstream end of the sealing cover 112 also has a downstream groove 116 that opens axially to the downstream.

[0070] According to the plane transverse to X, the groove 116 has a C-shaped cross section according to the longitudinal section.

[0071] The groove 116 may be located on the side of the radial outer surface of the annular portion 114.

[0072] The groove 116 can be formed by the downstream end of the annular portion 114 of the shroud and by a first dissimilar component 116a, which is attached to the downstream end of the annular portion 114, for example, by welding. Alternatively, this first dissimilar component 116a can be made as a single piece with the annular portion 114. According to one embodiment, a downstream annular seal 118 can be arranged in the downstream groove 116. The downstream annular seal 118 is located between the downstream end of the sealing shroud 112 and the upstream end of the radially inner annular wall 104.

[0073] The downstream annular seal 118 is formed of a braided annular element made of a textile material such as aluminosilicate.

[0074] Therefore, the downstream annular seal allows filling any annular gap axially located between the inner annular wall 104 and the sealing shield 112.

[0075] For example, the inner annular wall 104 and the outer annular wall 102 are made of metal or ceramic matrix composite (CMC) material.

[0076] The injection cone 100 includes a tapered downstream portion connected to an outer annular wall 102. The tapered downstream portion is made of a ceramic matrix composite material. The outer annular wall 102 may form a surface continuity with a portion of the exhaust housing to define a flow channel for the hot gas flow.

[0077] The downstream portion of the inner annular wall 104 can be attached to the downstream portion of the outer annular wall 102.

[0078] Figure 4 An assembly according to another embodiment is shown, which is related to the reference. Figure 2 and 3 The difference in the described assembly is that the sealing cover 112 further includes an upstream groove 120, which opens radially outward and accommodates an upstream annular seal 122 therein.

[0079] According to the plane transverse to X, the groove 120 has a C-shaped cross section according to the longitudinal section.

[0080] The groove can be located on the side of the radial outer surface of the cover 112.

[0081] The groove can be formed by a second dissimilar component 120a, which is attached, for example, by welding to the upstream end of the annular portion 114 of the cover 112. Of course, this second dissimilar component 120a can be made as a single piece with the annular portion 114.

[0082] The upstream annular seal 122 is located radially between the upstream end of the sealing cover 112 and the outer annular wall 102 of the injection cone 100.

[0083] The upstream annular seal 122 is formed of a braided annular element made of, for example, a silicate fabric.

[0084] Therefore, the upstream annular seal 122 allows filling of any annular gaps radially located between the outer annular wall 102 and the sealing shield 112.

[0085] The upstream annular seal 122 can deform radially to reduce the radial displacement of the outer annular wall 102.

[0086] Figure 5 and 6 Another embodiment is shown, which is consistent with the reference. Figure 2 and 3 The described embodiment differs in that the elastically deformable tabs 124 extend radially outward and axially upstream from the annular portion 114 of the sealing shield 112. The tabs 124 are evenly distributed on the circumference and spaced apart from each other along the circumference.

[0087] For example, the tab 124 is made as a single piece with the annular portion 114 of the sealing shield 112 by cutting and bending the upstream end of the annular portion 114.

[0088] The outer annular wall 102 is supported on the free end of the tab 124, which reduces radial displacement of the outer annular wall 102. For example, these radial displacements of the outer annular wall 102 are caused by the expansion of the upstream portion of the outer annular wall 102, which is due to thermomechanical stress experienced by the outer annular wall 102. This thermomechanical stress is partly due to the material differences between the conical downstream portion of the injection cone, the outer and inner annular walls, and the exhaust casing.

Claims

1. An assembly for a turbine, the assembly extending along an axis (X), comprising: - A jet cone (100) comprising a radially outer annular wall (102) defining a flow channel for a hot gas flow and an acoustic chamber radially disposed within the outer annular wall (102), the acoustic chamber comprising a radially inner annular wall (104). A connecting component (106) is inserted axially between the exhaust housing and the injection cone (100), the connecting component (106) including an upstream annular flange (108) fixedly attached to the exhaust housing and a plurality of downstream fixing tabs (110) connected to the radially inner annular wall (104). The assembly is characterized in that it includes an annular sealing shield (112), the annular sealing shield comprising an upstream portion of the retaining tabs (110) surrounding the connecting member (106) to cover the space circumferentially located between the retaining tabs (110) and axially located between the upstream annular flange (108) of the connecting member (106) and the radially inner annular wall (104). Furthermore, the assembly further includes: A downstream annular seal (118), which is installed at the downstream end of the sealing shield (112) and radially positioned relative to the radially inner annular wall (104) of the jet cone (100), or An upstream annular seal (122) is installed at the upstream end of the sealing shield (112) and is radially positioned relative to the outer annular wall (102) of the jet cone (100).

2. The assembly according to claim 1, characterized in that, The downstream end of the sealing cover (112) includes a groove (116) that opens downstream, and the downstream annular seal (118) is installed in the groove (116).

3. The assembly according to claim 2, wherein the sealing shield (112) is attached to the upstream annular flange (108) of the connecting member (106).

4. The assembly according to claim 1, characterized in that, The upstream end of the sealing cover (112) includes a radially outwardly opening groove (120), and the upstream annular seal (122) is installed in the groove (120).

5. The assembly according to any one of claims 1 to 4, characterized in that, The damping member is radially installed between the upstream end of the sealing cover (112) and the outer annular wall (102).

6. The assembly according to claim 5, characterized in that, The upstream annular seal (122) forms the damping member.

7. The assembly according to any one of claims 1 to 3, characterized in that, A damping member is radially mounted between the upstream end of the sealing shield (112) and the outer annular wall (102). The damping member is formed by an elastically deformable tab (124) extending radially from the sealing shield (112) or correspondingly from the outer annular wall (102), which is supported on the free end of the tab (124).

8. A turbine comprising an assembly according to any one of the preceding claims.

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