Annular sealing piece for moving turbine blades of a turbomachine

Abstract

This document relates to a turbine assembly for a longitudinally oriented turbomachine comprising: - a housing (8) having at least one downstream hook (12) on which is fixed a support (16) of an abradable material (14) intended to radially face an annular row of moving blades (2), characterized in that it comprises: - a sealing piece (20) structurally distinct from the support (16) of the abradable material (14), this sealing piece (20) being radially interposed between the abradable material (14) and the housing (8) and being sealed at its downstream end to the downstream hook (12) of the housing. Figure to be published with the abbreviation: Figure 1

Description

Title of the invention: Annular sealing piece for moving turbine blades of a turbomachine. Technical field

[0001] The invention relates to the field of aeronautical turbomachinery and more particularly to annular sealing parts for a moving blade of the turbomachine. Previous technique

[0002] Conventionally, a turbomachine comprises, from upstream (AM) to downstream (AV) according to the direction of gas flow within the turbomachine, a fan, a low-pressure compressor, a high-pressure compressor, an annular combustion chamber, a high-pressure turbine, and a low-pressure turbine. The rotor of the high-pressure compressor and the rotor of the high-pressure turbine are connected by a high-pressure shaft (HP) and together form a high-pressure housing. The rotor of the low-pressure compressor and the rotor of the low-pressure turbine are connected by a low-pressure shaft (LP) and together form a low-pressure housing. In the upstream section of the turbomachine, the fan has blades connected to a fan shaft which, in the example shown, is rotationally connected to the LP shaft via a reduction gear. The fan and the low-pressure compressor thus form an upstream low-pressure module of the turbomachine.The HP and LP shafts extend along the longitudinal X-axis of the turbomachine. The turbomachine also includes a fan casing that extends around the blades and defines an air intake duct for the airflow.

[0003] It is noted that in the present application: - axial or axially means: along the axis of rotation of the moving blade, or parallel to it, which axis is also the longitudinal axis of the turbomachine around which the (moving) blades of the turbine(s), compressor(s), and blower, if present, rotate. - "Radially" means transversely to the X axis, therefore along a Z axis; therefore, radially, external is what is further along the X axis than what is internal, and - "upstream" and "downstream" are understood axially, with respect to the general direction of flow of a fluid which enters upstream and exits downstream.

[0004] The turbine comprises a housing 8 surrounding a plurality of annular rows of movable blades 2 configured to rotate about the X-axis and arranged alternately along the X-axis with annular rows of fixed blades or distributor 4. An abradable material 14 is arranged radially outside the annular row of blades The mobile element 2 is supported by a support ring 16, the upstream end of which 17 comprises an upstream-oriented annular hook 19, which is held by the upstream annular hook 10 of the housing 8 by means of a C-shaped annular clamping element 18. The downstream annular end of the support ring 16 and the abradable material is supported by an upstream annular tab 32 of the downstream distributor 4. This upstream annular tab 32 comprises two radially internal and external annular flanges between which the support ring 16, the abradable material 14, and the downstream annular hook 12 of the housing are mounted. The seal between the downstream annular hook 12 and the support ring 16 is achieved by the radial bearing of these two parts against each other.This fastening method allows for easy upstream disassembly of the support ring 16 and the abradable material 14 of the first annular row of moving blades 2 of the low-pressure turbine, thus enabling rapid replacement of this assembly ([Fig. 1]). Indeed, after disassembly of the clamping element 18, the support ring 16 can be moved axially upstream. However, the seal between the downstream annular hook 12 and the support ring 16 needs improvement because the seal is achieved by the removable support ring 16. To improve the seal, one possibility would be to add axial contact between the support ring 16 and the downstream annular hook 12 of the housing. However, this solution no longer allows upstream dismantling of the support ring 16 and requires the removal of several annular rows of moving blades 2 and annular rows of fixed blades to access the desired support ring 16.

[0005] The invention aims to resolve at least some of the aforementioned drawbacks. Summary of the invention

[0006] This document relates to an assembly for a longitudinally axis turbomachine turbine comprising: - a housing comprising at least one downstream hook on which is fixed a support of an abradable material intended to radially face an annular row of movable blades

[0007] characterized in that it comprises: - a sealing piece structurally separate from the support of the abradable material, this sealing piece being interposed radially between the abradable material and the housing and being fixed to seal at its downstream end on the downstream hook of the housing.

[0008] The sealing function and the function performed by the abradable material are thus decoupled. Thanks to this configuration, the sealing piece remains permanently in place, ensuring the long-term sealing function required for the assembly. This sealing piece now allows the support ring to be disassembled with the The material can be abradable from upstream while keeping the sealing piece in place. This prevents leaks that could occur at the downstream hook. This sealing piece improves turbine performance. It is no longer necessary to disassemble the sealing piece, saving time. Replacing the abradable material is easy and cost-effective.

[0009] The downstream hook may be annular. It may be continuous over 360° or comprise a plurality of hook sectors arranged circumferentially end to end or circumferentially spaced from one another. The downstream hook may also be formed in one piece.

[0010] The support may be annular. It may be continuous over 360° or comprise a plurality of support sectors arranged circumferentially end to end or circumferentially spaced from one another. The support may also be formed from a single piece.

[0011] The sealing piece may be annular. It may be continuous over 360° or comprise a plurality of sealing piece sectors arranged circumferentially end to end or circumferentially spaced from one another. The sealing piece may also be formed from a single piece.

[0012] The sealing piece may include an upstream hook which, together with the downstream hook of the housing, provides radial retention of the sealing piece on the housing.

[0013] The upstream hook may be annular. It may be continuous over 360° or comprise a plurality of hook sectors arranged circumferentially end to end or circumferentially spaced from one another. The upstream hook may also be formed from a single piece.

[0014] Thanks to this downstream hook, better retention of the sealing piece is achieved, which further improves the sealing function performed by the sealing piece.

[0015] The sealing piece may include a downstream groove in which the downstream hook is clamped.

[0016] The downstream groove can be annular. It can be continuous over 360° or over an angular part of the sealing piece.

[0017] This downstream groove makes it easier to fit the sealing piece with the downstream hook of the housing.

[0018] An upstream end of the sealing piece can be held radially between an upstream end of the support and an upstream hook of the housing.

[0019] A better fit of the sealing piece is thus obtained.

[0020] The sealing piece may include an upstream end bearing radially on a radially external face of the support.

[0021] The upstream end of the sealing piece can be interposed longitudinally between an upstream hook of the housing and the downstream hook

[0022] The positioning of the sealing piece between the upstream annular hook of the housing and the downstream hook of the housing ensures a good hold of the sealing piece and ease of assembly.

[0023] A seal can be interposed longitudinally between the downstream hook of the housing and an upstream leg of a downstream distributor.

[0024] The seal may be annular. It may be continuous over 360° or comprise a plurality of seal sectors arranged circumferentially end to end or circumferentially spaced from one another. The seal may also be formed from a single piece.

[0025] The seal makes it possible to significantly improve the sealing between the downstream hook of the housing and the upstream leg of the downstream distributor and to prevent possible leaks.

[0026] The upstream leg of the downstream distributor can be applied radially inwards on a downstream end of the sealing piece or on the downstream hook.

[0027] The sealing piece can be formed of several sectors arranged circumferentially end to end.

[0028] The support can be formed of several sectors, each sector being held radially by form connection at the junction of two sectors of the sealing piece.

[0029] Each sector of the support can include a longitudinal rail with a T-shaped cross-section extending radially outwards, a first branch of which is engaged in a slot of a first sector of the annular sealing piece and a second branch is engaged in a slot of a second sector circumferentially adjacent to the first sector.

[0030] This longitudinal rail allows for easy assembly and excellent holding of the support ring sector with the longitudinal rail. Brief description of the drawings

[0031] [Fig-1] represents a turbomachine turbine assembly comprising a abradable according to prior art,

[0032] [Fig.2] represents a turbomachine turbine assembly comprising an annular sealing piece according to a first embodiment of the invention,

[0033] [Fig.3] represents a turbomachine turbine assembly comprising an annular sealing piece according to a second embodiment of the invention,

[0034] [Fig.4] represents a turbomachine turbine assembly comprising an annular sealing piece according to a third embodiment of the invention,

[0035] [Fig.5] represents a 3D view of the turbomachine turbine assembly including the annular sealing piece according to the third embodiment of the invention illustrated in [Fig.4],

[0036] [Fig.6] represents a 3D view of an arrangement of a support ring comprising an abradable material with an annular sealing piece according to the third embodiment of the invention illustrated in [Fig.4] and 5,

[0037] [Fig.7] represents a 3D view of an interlocking between a longitudinal rail of a support ring according to the third embodiment with the sectorized sealing annular piece,

[0038] [Fig.8] represents a schematic view of the longitudinal rail with the sectorized annular sealing piece illustrated in [Fig.6]. Description of the implementation methods

[0039] As illustrated in Figures 2, 3 and 4, this document applies to a casing 8 of a turbomachine turbine.

[0040] The housing 8 includes means for fixing a support ring 16 to which is fixed an abradable material 14 and a sealing piece 20. These means include a downstream annular hook 12 and an upstream annular hook 10.

[0041] The downstream annular hook 12 has an L-shaped form. The downstream annular hook 12 has a radial annular wall 22 extending radially inwards. The radial annular wall 22 is connected at an inner radial end to a cylindrical wall 24 extending downstream. This downstream annular hook 12 is said to be oriented downstream.

[0042] The upstream annular hook 10 has an L-shaped form. The upstream annular hook 10 has a radial annular wall 26 extending radially inwards. This radial annular wall 26 of the upstream annular hook 10 is connected at an inner radial end to a cylindrical wall 28 extending upstream. This upstream annular hook 10 is said to be oriented downstream.

[0043] A distributor 4 is located downstream of said downstream annular hook 12. This distributor 4 comprises a plurality of fixed vanes 4. The distributor includes a radial annular platform 30 from which extends an annular arm 32. This annular arm 32 extends radially outwards. The annular arm 32 comprises a succession of four annular walls: a frustoconical wall 34 with a cross-section extending upstream, a cylindrical wall 36, a radial annular wall 38, and a cylindrical wall 40.

[0044] An annular seal 42 is interposed longitudinally between the downstream annular hook 12 of the housing 8 and the annular tab 32 of the downstream distributor 4. More specifically, the annular seal 42 has a first end 44 that comes into contact with the wall radial 22 extending radially towards the inside of the downstream annular hook 12 and a second end 46 coming into contact with the radial annular wall 38 of the annular leg 32 of the distributor 4.

[0045] The support ring 16 for the abradable material 14 is fixed to the inner periphery of said housing 8. The support ring 16 is formed of several sectors; it is said that this support ring 16 is sectorized. The abradable material 14 is radially aligned with an annular row of movable blades 2. An upstream end 48 of the support ring 16 is held tightly on the upstream annular hook 10 by a clamping member 18. This clamping member 18 comprises a first part 50 including a C-shape and a second part 52 including an L-shape.

[0046] The sealing annular piece 20 is radially interposed between the support ring 16 of abradable material 14 and the housing 8. The sealing annular piece 20 comprises a first part 54 and a second part 56. The first part 54 of the sealing annular piece 20 has an annular wall 58.

[0047] According to a particular embodiment illustrated in [Fig.2], the second part 56 of the annular sealing piece 20 comprises a downstream end 60 including an annular hook 62. The annular hook 62 of the second part 56 of the annular sealing piece 20 comprises a radial wall 64 extending radially outwards connected to a cylindrical wall 66 extending upstream. The cylindrical wall 66 extending upstream of the annular hook 62 of the second part 56 of the annular sealing piece 20 has an internal face which contacts an external face of the cylindrical wall 24 extending downstream of the downstream annular hook 12. The cylindrical wall 66 extending upstream of the annular hook 62 of the second part 56 of the annular sealing piece 20 has an external face which contacts an internal face of the cylindrical wall 36 of the tab 32 of the distributor 4.

[0048] According to a particular embodiment illustrated in Figures 3 and 4, the annular sealing piece 20 is sectorized, that is to say, formed of several sectors arranged circumferentially end to end. The first part 54 of the annular sealing piece 20 comprises an upstream annular end 59 held tightly by the clamping member 18 on an inner face of the cylindrical wall 28 of the upstream annular hook 10. The second part 56 comprises a groove 61 configured to receive an inner face of the cylindrical wall 24 extending downstream of the downstream annular hook 12. Said groove 61 comprises a stop element 63 entering into contact with the cylindrical wall 24 extending downstream of the downstream annular hook 12. The groove 61 is adapted to clamp the stop element 63 and reduce potential leaks.

[0049] According to a particular embodiment illustrated in Figures 4 to 7, the radial annular wall 22 of the downstream annular hook 12 extends to an external radial end by a cylindrical wall 66. The radial annular wall 40 of the lug 32 comprises a radially external face that is applied to a radially internal face of the cylindrical wall 66 located at the outer radial end of the downstream annular hook 12. The sealing annular piece 20 is sectored. Each sector of the support ring comprises a longitudinal rail 68 with a T-section extending radially outwards. A first leg 70 of this T-section longitudinal rail 68 is engaged in a slot 72 of a first sector 71 of the sealing annular piece 20. A second leg 74 of the T-section longitudinal rail 68 is engaged in a slot 76 of a second sector 73 circumferentially adjacent to the first sector 71. Each sector of the support ring 16 is retained radially by a form connection at the junction of the first 71 and second 73 sectors of the sealing annular piece 20.

Claims

Demands

1. Assembly for a longitudinally oriented turbomachine turbine comprising: - a housing (8) having at least one downstream hook (12) on which is fixed a support (16) of an abradable material (14) intended to radially face an annular row of moving blades (2), said at least one downstream hook (12) comprising a radial annular wall (22) extending radially inwards, characterized in that it comprises: - a sealing piece (20) structurally distinct from the support (16) of the abradable material (14), this sealing piece (20) being radially interposed between the abradable material (14) and the housing (8) and being sealed at its downstream end to the downstream hook (12) of the housing, in which a seal (42) is longitudinally interposed between the downstream hook (12) of the housing (8) and an upstream tab (32) from a downstream distributor (4),in which the annular seal (42) has a first end (44) coming into contact with the radial annular wall (22) of said at least one downstream hook (12) and a second end (46) coming into contact with a radial annular wall (38) of the upstream leg (32) of the downstream distributor (4).

2. Assembly according to claim 1, wherein the housing (8) includes an upstream hook (10) which together with the downstream hook (12) provides radial retention of the sealing piece (20) on the housing (8).

3. Assembly according to claim 1 or 2, wherein the sealing piece (20) includes a downstream groove (61) in which the downstream hook (12) is mounted.

4. Assembly according to claim 1 to 3, wherein an upstream end of the sealing piece (20) is held radially between an upstream end of the support (16) and an upstream hook (10) of the housing (8).

5. Assembly according to any one of claims 1 to 3, wherein the sealing piece (20) comprises an upstream end bearing radially on a radially external face of the support (16).

6. Assembly according to claim 5, wherein the upstream end of the sealing piece (20) is interposed longitudinally between an upstream hook (10) of the housing and the downstream hook (12).

7. Assembly according to any one of the preceding claims, wherein the upstream leg (32) of the downstream distributor (4) is applied radially inward to a downstream end of the sealing piece (20) or to the downstream hook (12).

8. Assembly according to any one of the preceding claims, wherein the sealing piece (20) is formed of several sectors arranged circumferentially end to end.

9. Assembly according to the preceding claim, wherein the support (16) is formed of several sectors, each sector being retained radially by form connection at the junction of two sectors of the sealing piece (20).

10. Assembly according to the preceding claim, wherein each support sector (16) comprises a longitudinal rail (68) with a T-shaped cross-section extending radially outwards, a first branch (70) of which is engaged in a slot (72) of a first sector (71) of the sealing piece (20) and a second branch (74) of which is engaged in a slot (76) of a second sector (73) circumferentially adjacent to the first sector.

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