Assembly for a turbine engine, comprising a sealing element, and sealing element for such an assembly for a turbine engine

Abstract

The invention relates to an assembly for a turbine engine, the assembly comprising a first casing (20), a second casing (22), an abradable ring support (37) carried by the first casing (20), an annular seal (40, 54) arranged between the first casing (20) and the second casing (22), and a sealing element (42) at least partially arranged between the annular seal (40, 54) and the second casing (22), the sealing element (42) comprising an annular part (44) that has a first face (46) in contact with the annular seal (40, 54), and a second face (48) opposite the first face (46) and in contact with the second casing (22).

Description

[0001] DESCRIPTION

[0002] TITLE: Turbomachine assembly comprising a sealing element and sealing element for such a turbomachine assembly

[0003] Technical field

[0004] The technical field of the invention is the sealing of a turbomachine, in particular the sealing of an air flow from the turbomachine at a connection between two casings of the turbomachine.

[0005] In particular, the present invention relates to a turbomachine assembly comprising a sealing element and a sealing element for such a turbomachine assembly.

[0006] Previous techniques

[0007] A turbomachine comprises a turbine having several turbine stages and a turbine casing. Each turbine stage comprises an annular row of fixed blades and an annular row of moving blades rotating inside the casing. The fixed blades each comprise an inner platform and an outer platform delimiting a flow path for hot gases from a combustion chamber upstream of the turbomachine. The moving blades each comprise an inner platform.

[0008] The turbomachine comprises a downstream exhaust casing and a seal arranged at the connection between the exhaust casing and the turbine casing in order to ensure the sealing, in particular thermal sealing, of said connection.

[0009] The rotating elements of the turbomachine, the temperature variations experienced by the various elements of the turbomachine and the gas pressures cause relative movements of the seal with respect to the turbine casing and / or the exhaust casing. These relative movements cause premature wear of the seal and / or the turbine casing and / or the exhaust casing. This premature wear degrades the sealing of the connection between the exhaust casing and the turbine casing, degrades the efficiency of the turbomachine and generates high maintenance costs.

[0010] Statement of the invention

[0011] The present invention therefore aims to overcome all or part of the aforementioned drawbacks.

[0012] The present invention relates to an assembly for a turbomachine, the assembly comprising a first casing, a second casing, an abradable ring support carried by the first casing, an annular seal arranged at least in part between the abradable ring support and the second casing, and a sealing element arranged at least in part between the annular seal and the second casing, the sealing element comprising an annular part provided with a first face in contact with the annular seal, and provided with a second face opposite the first face and in contact with the second casing.

[0013] The sealing element in contact with the annular seal and the second casing increases the compression of the annular seal, increases the effectiveness of the sealing function of the annular seal and protects the second casing from wear caused by the movement of the annular seal. The cost of replacing the sealing element is also lower than the cost of replacing the second casing. The replacement time of the sealing element is also lower than the replacement time of the second casing.

[0014] Preferably, the turbomachine assembly comprises a turbine, in particular a low-pressure turbine.

[0015] In a particular embodiment, the first casing is a casing surrounding said turbine in the circumferential direction, the second casing being a casing upstream or downstream of said turbine.

[0016] Advantageously, the sealing element comprises a nickel-based alloy.

[0017] The sealing element may comprise at least one large diameter centering portion extending at least axially a large diameter edge of the annular part. Said large diameter centering portion may be in contact with the first casing.

[0018] The sealing element may comprise at least one small diameter centering portion extending at least axially a small diameter edge of the annular part.

[0019] Said small diameter centering portion may be in contact with the second casing.

[0020] In one embodiment, said large diameter centering portion extends at least axially the large diameter edge of the annular part in a first direction, said small diameter centering portion extending at least axially the small diameter edge of the annular part in a second direction, the first direction being opposite to the second direction.

[0021] According to a particular design, the sealing element further comprises an additional annular part which is connected to the annular part by said small diameter centering portion, and which extends at a distance from and opposite the annular part.

[0022] Preferably, the additional annular part is in contact with the second housing.

[0023] Advantageously, the annular part comprises an excess thickness, the additional annular part comprising an excess thickness, said excess thicknesses locally reducing the distance between the annular part and the additional annular part.

[0024] Optionally, the first casing is a low pressure turbine casing for a turbomachine.

[0025] Optionally, the second casing is an exhaust casing for a turbomachine.

[0026] Advantageously, the turbomachine assembly comprises an abradable ring mounted on the abradable ring support, the annular seal comprising at least two convolutions and partly circumferentially surrounding the abradable ring.

[0027] The present invention also relates to a sealing element suitable for a turbomachine assembly as defined above, the sealing element being intended to be arranged at least partly between the annular seal and the second casing, the sealing element comprising an annular part provided with a first face intended to be in contact with the annular seal, and provided with a second face opposite the first face and intended to be in contact with the second casing.

[0028] According to a first design, the sealing element comprises at least a first centering portion extending at least axially a large diameter edge of the annular part in a first direction and at least a second centering portion extending at least axially a small diameter edge of the annular part in a second direction, the first direction being opposite to the second direction.

[0029] According to a second design, the sealing element comprises at least one small diameter centering portion extending at least axially a small diameter edge of the annular part and an additional annular part which is connected to the annular part by said small diameter centering portion, and which extends at a distance from and opposite the annular part.

[0030] Advantageously, the annular part comprises an excess thickness, the additional annular part comprising an excess thickness, said excess thicknesses locally reducing the distance between the annular part and the additional annular part.

[0031] The said sealing element is, for example, a spare part.

[0032] The present invention also relates to a turbomachine comprising a turbomachine assembly as defined above.

[0033] The present invention also relates to an aircraft comprising a turbomachine as defined above.

[0034] Brief description of the drawings

[0035] Other aims, characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings in which: [Fig 1] schematically illustrates a turbomachine comprising a turbomachine assembly according to the invention;

[0036] [Fig 2] schematically illustrates a flow vein of a low pressure turbine of the turbomachine of figure 1;

[0037] [Fig 3] is an enlargement of a portion of Figure 2 centered on a sealing element according to the invention;

[0038] [Fig 4] schematically illustrates a sealing element according to the invention;

[0039] [Fig 5] is a view corresponding to Figure 3 according to a second exemplary embodiment of the invention; and

[0040] [Fig 6] schematically illustrates a sealing element according to a third exemplary embodiment of the invention.

[0041] Detailed description

[0042] Figure 1 schematically represents an aircraft turbomachine 2 comprising a low pressure body comprising a first shaft 4 and a high pressure body comprising a second shaft 6, the second shaft 6 being concentric with the first shaft 4.

[0043] The low pressure body comprises a blower 8, a low pressure compressor 10 and a low pressure turbine 12.

[0044] The high pressure body comprises a high pressure compressor 14, a combustion chamber 16 and a high pressure turbine 18.

[0045] Figure 2 schematically represents a part of the turbomachine 2 centered on an assembly comprising a turbine casing 20 surrounding in the circumferential direction the low pressure turbine 12, an exhaust casing 22 in the axial extension and downstream of the turbine casing 20 and a fixing element 24 of the exhaust casing 22 to the turbine casing 20.

[0046] The axial direction is the direction along the longitudinal dimension of the turbomachine 2, the radial direction being orthogonal to the axial direction, the circumferential direction corresponding to the direction of rotation of the first shaft 4.

[0047] The upstream and downstream sides are considered according to the direction of flow of the hot gases coming from the combustion chamber 16 of the turbomachine 2. The low-pressure turbine 12 comprises several turbine stages, each comprising an annular row of fixed blades 26 and an annular row of moving blades 28 rotating inside the turbine casing 20. The fixed and moving blades 26, 28 each comprise an internal platform 30 and an external platform 32.

[0048] The internal platforms 30 and the external platforms 32 delimit a flow vein 34 of hot gases coming from the combustion chamber 16 of the turbomachine 2.

[0049] The outer platforms 32 of the moving blades 28 comprise wipers 36 spaced axially from each other and extending radially outwardly.

[0050] The fixed blades 26 are fixed by hooks to rails (not shown) of the turbine casing 20.

[0051] The turbine casing 20 of the assembly is provided with a plurality of abradable ring supports 37 each supporting an abradable ring 38, in particular a sectorized abradable ring 38. Each abradable ring support 37 extends radially inward from the inner surface of the turbine casing 20 so that each abradable ring 38 faces the wipers 36 of an outer platform 32 of a moving blade 28. The abradable rings 38 cooperate with the wipers 36 in order to participate in the sealing of the flow vein 34.

[0052] The assembly also comprises an annular seal 40, visible in more detail in FIG. 3, arranged between the exhaust casing 22 and an abradable ring support 37 of the turbine casing 20 in order to ensure the sealing, in particular thermal sealing, of the flow vein 34 at the connection between the exhaust casing 22 and the turbine casing 20.

[0053] More precisely, the annular seal 40 surrounds in the circumferential direction of the turbomachine 2 the abradable ring 38 opposite the wipers 36 of the external platform 32 of the moving blade 28 located furthest downstream of the low pressure turbine 12. The annular seal 40 here comprises a section in the shape of a tiny omega, the annular seal 40 comprising two convolutions. The annular seal 40 is in contact on the upstream side with the abradable ring support 37 furthest downstream of the low pressure turbine.

[0054] The annular seal 40 extends axially from the abradable ring support 37 furthest downstream of the low pressure turbine 12 towards the exhaust casing 22.

[0055] The assembly includes a sealing element 42, also shown in Figure 4, disposed partly between the annular seal 40 and the exhaust casing 22.

[0056] The sealing element 42 comprises an annular part 44 surrounding the first shaft 4 in the circumferential direction and arranged axially between the annular seal 40 of the assembly and the exhaust casing 22 of the assembly. The annular part 44 extends here purely radially.

[0057] The annular part 44 is provided with a first face 46, on the upstream side of the turbomachine 2, in contact with the annular seal 40.

[0058] The annular part 44 is provided with a second face 48, on the downstream side of the turbomachine 2, in contact with the exhaust casing 22.

[0059] The sealing element 42 cooperates with the annular seal 40 in order to ensure the sealing of the flow vein 34 at the connection between the turbine casing 20 and the exhaust casing 22.

[0060] The thickness of the annular part 44, according to the longitudinal dimension of the turbomachine 2, increases the axial stress on the annular seal 40. The annular seal 40 being more compressed, the wear tolerance at the axial ends of the annular seal 40, in particular without loss of thermal sealing, is increased.

[0061] The annular part 44 makes it possible to protect the exhaust casing 22 from contact with the annular seal 40, in particular from friction of the annular seal 40.

[0062] The sealing element 42 comprises, for example, a nickel-based alloy, in particular in order to have high resistance to corrosion, oxidation and high temperatures characteristic of the turbomachine environment 2.

[0063] Advantageously, the sealing element 42 comprises a first centering portion 50, or large diameter centering portion 50, axially extending the large diameter edge of the annular part 44, the first centering portion 50 extending here upstream of the turbomachine 2 and at a distance from the annular seal 40. The first centering portion 50 extends here purely axially. Alternatively, the first centering portion 50 could extend both axially and radially and / or could extend downstream of the turbomachine 2.

[0064] The turbine casing 20 comprises a wall of complementary shape to the first centering portion 50 in contact with the first centering portion 50. Said wall notably forms radial stops radially retaining the sealing element 42.

[0065] Advantageously, the sealing element 42 comprises a second centering portion 52, or small diameter centering portion 52, axially extending the small diameter edge of the annular part 44, the second centering portion 52 extending here downstream of the turbomachine 2. The second centering portion 52 extends here purely axially. Alternatively, the second centering portion 52 could extend both axially and radially and / or could extend upstream of the turbomachine 2.

[0066] The second centering portion 52 bears radially against the exhaust casing 22 in order to radially retain the sealing element 42.

[0067] The first and second centering portions 50, 52 are here annular. Alternatively, the sealing element 42 comprises several centering portions spaced apart from each other in the circumferential direction, the centering portions then forming centering tabs.

[0068] The sealing element 42 is a less expensive and simpler consumable to replace than the exhaust housing 22.

[0069] Optionally, the turbomachine 2 comprises an additional sealing element (not shown) of the same nature as the sealing element 42 and arranged at least in part between the turbine casing 20 and the annular seal 40, in particular arranged at least in part between the abradable ring support 37 furthest downstream of the low-pressure turbine 12 and the annular seal 40, or arranged at least in part between a casing of the turbomachine 2 and another annular seal 54 of the turbomachine 2. Said other annular seal 54 is, for example, arranged at the junction between the low-pressure turbine 12 and the high-pressure turbine 18, said other annular seal 54 and the additional sealing element jointly ensuring the sealing of the flow stream 34 at the connection between the turbine casing 20 and a casing surrounding the high-pressure turbine 18 in the circumferential direction.

[0070] The second embodiment illustrated in Figure 5 differs from the first embodiment illustrated in Figures 1 to 4 in that the sealing element 42 is devoid of the large diameter centering portion and is further provided with an additional annular part 44' which is connected to the annular part 44 by the small diameter centering portion 52, and which extends at a distance from and opposite the annular part 44. The additional annular part 44' is here identical to the annular part 44. Alternatively, the additional annular part 44' could extend both axially and radially, i.e. obliquely, towards the annular part 44.

[0071] More precisely, the small diameter centering portion 52 extends, on the one hand, axially and downstream the small diameter edge of the annular part 44, and on the other hand, axially and upstream the small diameter edge of the annular part the additional annular part 44'. The small diameter centering portion 52 extends here purely axially.

[0072] The annular part 44 is axially in contact with the annular seal 40 and with the exhaust casing 22.

[0073] The small diameter centering portion 52 is radially in contact with the exhaust casing 22. In particular, the outside diameter of the small diameter centering portion 52 is greater than the inside diameter of the exhaust casing 22 so that the small diameter centering portion 52 is pressed against the exhaust casing 22 and does not move during operation of the turbomachine 2.

[0074] The additional annular part 44' is provided with an upstream face which is axially in contact with the exhaust casing 22.

[0075] The third embodiment illustrated in Figure 6 differs from the second embodiment illustrated in Figure 5 in that the annular part 44 and the additional annular part 44' are each of variable thickness. In particular, the annular part 44 and the additional annular part 44' respectively comprise an excess thickness 56, 56' so as to locally reduce the axial distance between the annular part 44 and the additional annular part 44'.

[0076] The excess thickness 56 of the annular part 44 is formed at a distance from the radially outer end of the annular part 44 and at a distance from the small diameter centering portion 52. Similarly, the excess thickness 56' of the additional annular part 44' is formed at a distance from the radially outer end of the additional annular part 44' and at a distance from the small diameter centering portion 52. Thus, the sealing element 42 is pinched on the exhaust casing 22, the excess thicknesses 56, 56' being in contact with the exhaust casing 22.

Claims

CLAIMS 1. A turbomachine assembly (2), the assembly comprising a first casing (20), a second casing (22), an abradable ring support (37) carried by the first casing (20) and an annular seal (40, 54) arranged at least in part between the abradable ring support (37) and the second casing (22), characterized in that it comprises a sealing element (42) arranged at least in part between the annular seal (40, 54) and the second casing (22), the sealing element (42) comprising an annular part (44) provided with a first face (46) in contact with the annular seal (40, 54), and provided with a second face (48) opposite the first face (46) and in contact with the second casing (22).

2. Turbomachine assembly (2) according to claim 1, in which the sealing element (42) comprises at least one large diameter centering portion (50) extending at least axially a large diameter edge of the annular part (44).

3. Turbomachine assembly (2) according to claim 2, wherein said large diameter centering portion (50) is in contact with the first casing (20).

4. Turbomachine assembly (2) according to any one of claims 1 to 3, in which the sealing element (42) comprises at least one small diameter centering portion (52) extending at least axially a small diameter edge of the annular part (44).

5. Turbomachine assembly (2) according to claim 4, wherein said small diameter centering portion (52) is in contact with the second casing (22).

6. Turbomachine assembly (2) according to one of claims 4 and 5 dependent on one of claims 2 and 3, in which said large diameter centering portion (50) extends at least axially the large diameter edge of the annular part (44) in a first direction, said small diameter centering portion (52) extending at least axially the small diameter edge of the annular part (44) in a second direction, the first direction being opposite to the second direction.

7. Turbomachine assembly (2) according to any one of claims 4 to 6, in which the sealing element (42) further comprises an additional annular part (44') which is connected to the annular part (44) by said small diameter centering portion (52), and which extends at a distance from and opposite the annular part (44).

8. Turbomachine assembly (2) according to claim 7, in which the additional annular part (44') is in contact with the second casing (22).

9. Turbomachine assembly (2) according to claim 7 or 8, wherein the annular part (44) comprises an excess thickness (56), the additional annular part (44') comprising an excess thickness (56'), said excess thicknesses (56, 56') locally reducing the distance between the annular part (44) and the additional annular part (44').

10. Assembly for a turbomachine (2) according to any one of claims 1 to 9, in which the first casing (20) is a low pressure turbine casing (12) for a turbomachine (2) and / or in which the second casing (22) is an exhaust casing for a turbomachine (2). 1 1. Turbomachine assembly (2) according to any one of claims 1 to 10, comprising an abradable ring (38) mounted on the abradable ring support (37), the annular seal (40, 54) comprising at least two convolutions and partly circumferentially surrounding the abradable ring (38).

12. Turbomachine assembly (2) according to any one of claims 1 to 11, in which the sealing element (42) comprises a nickel-based alloy.

13. Sealing element suitable for a turbomachine assembly (2) according to any one of claims 1 to 12, the sealing element (42) being intended to be arranged at least partly between the annular seal (40, 54) and the second casing (22), the sealing element (42) comprising an annular part (44) provided with a first face (46) intended to be in contact with the annular seal (40, 54), and provided with a second face (48) opposite the first face (46) intended to be in contact with the second casing (22), the sealing element (42) comprising at least a first centering portion (50) extending at least axially a large diameter edge of the annular part (44) in a first direction and at least a second centering portion (52) extending at least axially a small diameter edge of the annular part (44) in a second direction, the first direction being opposite to the second direction.

14. Sealing element suitable for a turbomachine assembly (2) according to any one of claims 1 to 12, the sealing element (42) being intended to be arranged at least partly between the annular seal (40, 54) and the second casing (22), the sealing element (42) comprising an annular part (44) provided with a first face (46) intended to be in contact with the annular seal (40, 54), and provided with a second face (48) opposite the first face (46) intended to be in contact with the second casing (22), the sealing element (42) comprising at least one small diameter centering portion (52) extending at least axially a small diameter edge of the annular part (44) and an additional annular part (44') which is connected to the annular part (44) by said small diameter centering portion (52), and which extends at a distance from and opposite the annular part (44).

15. Sealing element suitable for a turbomachine assembly (2) according to claim 14 in which the annular part (44) comprises an excess thickness (56), the additional annular part (44') comprising an excess thickness (56'), said excess thicknesses (56, 56') locally reducing the distance between the annular part (44) and the additional annular part (44').

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