Sealing strip for a turbine of a turbine engine

Abstract

The present document relates to a sealing strip (30a, 30b, 30c, 30d) for a turbine of a turbine engine, in particular for a turbine wheel, extending in a first direction (L1) and a second direction (L2) which are substantially perpendicular to each other, the strip comprising a first portion (32) and a second portion (34) which are connected to each other by an intermediate portion (36a, 36b, 36c, 36d) in the first direction, wherein the first portion (32) and the second portion (34) are substantially planar in the first direction (L1) and the second direction (L2) and wherein the intermediate portion (36a, 36b, 36c, 36d) is shaped so as to have a lower rigidity than the first portion (32) and the second portion (34) in a third direction (L3) perpendicular to the first direction (L1) and the second direction (L2).

Description

Description Title: Sealing blade for turbomachine turbine technical field

[0001] This document concerns the field of sealing fins for turbine ring sectors as well as a ring containing such fins. Previous technique

[0002] Figure 1 represents a twin-spool, twin-flow turbomachine 1. The axis of the turbomachine is referenced as X and corresponds to the axis of rotation of the rotating parts. In what follows, the terms axial and radial are defined with respect to the X-axis.

[0003] The turbomachine 1 comprises, from upstream to downstream in the direction of gas flow, a blower 2, a low pressure compressor 3, a high pressure compressor 4, a combustion chamber 5, a high pressure turbine 6 and a low pressure turbine 7.

[0004] The air from the blower 2 is divided into a primary flow 8 flowing into a primary annular vein 9, and a secondary flow 10 flowing into a secondary annular vein 11 surrounding the primary annular vein 10.

[0005] The low pressure compressor 3, the high pressure compressor 4, the combustion chamber 5, the high pressure turbine 6 and the low pressure turbine 7 are provided in the primary vein 9.

[0006] The rotor of the high-pressure turbine 6 and the rotor of the high-pressure compressor 4 are coupled in rotation via a first shaft 12 so as to form a high-pressure body.

[0007] The rotor of the low-pressure turbine 7 and the rotor of the low-pressure compressor 3 are coupled in rotation via a second shaft 13 so as to form a low-pressure body, the blower 2 being able to be connected directly to the rotor of the low-pressure compressor 3 or via an epicyclic gear train for example.

[0008] As can be more clearly seen in Figure 2, the low-pressure turbine 7 comprises, in particular, several successive stages including rotating runners 14 and stationary parts. The rotating runner has a disc 15 on which blades 16 are mounted. The ends of the blades 16 are surrounded by a fixed ring 17 made of abradable material, said ring 17 being fixed to the turbine housing 18. Distributors 19 are located downstream of the rotating runners 14. The distributors 19 and the rings 17 are mounted on the housing by means of flanges or hooks 20 extending from the radially internal surface of the housing 18.

[0009] Each ring 17 is sectorized, that is, it is composed of several angular sectors 21 arranged contiguously. A sector 21 of ring 17 is shown in Figure 3. Each sector 21 has a radially external part 22 and a radially internal part formed by a block of abradable material 23 fixed, for example by brazing, on the radially internal surface 24 of the external part 22. The circumferential ends of the support have slots 25 in which sealing strips 26 are mounted extending between the sectors 21, as illustrated in figure 4.

[0010] The use of sectors helps to compensate for the effects of thermal expansion during operation and the fins help to prevent or limit leaks of hot gas outside the primary stream.

[0011] Mounting the lamellae 26 between the sectors is relatively tedious, primarily due to the small size of the lamellae 26 and the slots 25. Indeed, a radial offset between two circumferentially facing slots can make mounting the lamella difficult, or even impossible (Figure 4B). In such a configuration, it may be necessary to remove one of the sectors and replace it with a sector having a slot positioned to accommodate a lamella. Furthermore, as illustrated in Figure 4A, the lamellae can have complex shapes formed from several parts, allowing insertion into several slots 25 of the circumferential edges of the sectors 21, which further stiffens the lamellae 26 and complicates their mounting even more. Summary

[0012] This document relates to a sealing flap for a turbomachine turbine, in particular for a turbine wheel, extending along a first direction and a second direction substantially perpendicular to each other, comprising a first part and a second part connected to each other by an intermediate part along the first direction, in which the first part and the second part are substantially planar along the first and second directions and in which the intermediate part is shaped so as to exhibit a lower stiffness than the first and second parts along a third direction perpendicular to the first and second directions.

[0013] According to the invention, varying the rigidity of the intermediate part and lowering its rigidity relative to the first and second parts allows for the creation of an intermediate section that permits the angulation of the first part relative to the second part. This intermediate section acts as a pivot whose axis lies in the plane formed by the first and second directions.

[0014] According to another characteristic, the intermediate part comprises at least two segments extending along the third direction, a first segment of said two segments extending along a first direction of the third direction and a second segment extending along a second direction of the third direction, the first direction being opposite to the second direction.

[0015] According to this document, the lamella thus comprises an intermediate part, which is a median portion because it is intercalated along the first direction, and the second part along the first direction, this second part comprising two segments whose conformation follows the The third direction makes it possible to facilitate the angular deformation of the first portion relative to the third part by means of the intermediate part.

[0016] The first segment and the second segment can be directly connected to each other.

[0017] According to this configuration, the first segment and the second segment can each have a common end connecting the two segments together and an opposite end connected respectively to the first part and the second part.

[0018] The first segment and the second segment can be connected to each other by a third segment.

[0019] The intermediate part may comprise N segments arranged successively one after the other so as to form one or more successive undulations.

[0020] In a particular embodiment of the invention, the undulations are linearly shaped.

[0021] The lamella may have a generatrix along the first direction and a director along a direction extending at least along the second direction.

[0022] The director can extend along the second direction.

[0023] The lamella may exhibit a plane of symmetry extending along the second and third directions.

[0024] The lamella may exhibit a central axis of symmetry along an axis extending along the second and third directions.

[0025] The lamella can have a substantially constant thickness from one end of the lamella to the other along the first direction.

[0026] The intermediate part may comprise two pairs of segments symmetrical to each other with respect to a plane comprising the first direction and the third direction, said two pairs of segments being connected to each other by a segment in C.

[0027] This shape allows for good flexibility in the middle section while having a reduced footprint in the first direction.

[0028] The C-shaped segment may exhibit a concavity oriented along the third direction.

[0029] This document also relates to a sectorized ring, in particular a turbine ring, comprising a plurality of sectors arranged circumferentially end to end and each comprising a slot at each circumferential end, a blade according to one of the preceding claims being mounted in a slot of a sector and in a circumferentially opposite slot of a circumferentially adjacent sector. Brief description of the drawings

[0030] Other features, details, and advantages will become apparent upon reading the detailed description below and analyzing the attached drawings, on which:

[0031] [Fig. 1] is an axial cross-sectional view of a prior art turbofan engine,

[0032] [Fig. 2] is an axial cross-sectional view of part of a prior art turbojet engine, illustrating in particular the low-pressure turbine,

[0033] [Fig. 3] is a detailed perspective view illustrating part of a sectorized turbine ring from the prior art,

[0034] [Fig. 4] is a schematic view illustrating the problem of assembling a complex lamella in a plurality of circumferentially facing sector slots,

[0035] [Fig. 5] comprises several parts, each illustrating an embodiment of a slat according to the invention and along a cutting plane comprising a first direction and a third direction perpendicular to each other. Detailed description of the invention

[0036] We now refer to Figure 5, which depicts several embodiments of the invention of a lamella 30a, 30b, 30c, 30d. In each embodiment, the lamella 30a, 30b, 30c, 30d extends along a first direction L1 and a second direction L2, substantially perpendicular to each other. In Figure 5, the second direction L2 corresponds to a direction perpendicular to the plane of the figure. A third direction L3 is formed by the direction perpendicular to the first and second directions L1 and L2.The lamella 30a, 30b, 30c, 30d comprises a first part 32 and a second part 34 connected to each other by an intermediate portion 36a, 36b, 36c, 36d along the first direction L1, wherein the first part 32 and the second part 34 are substantially planar along the first direction L1 and the second direction L2, and wherein the intermediate portion 36a, 36b, 36c, 36d is shaped to exhibit lower rigidity than the first part 32 and the second part 34 along a third direction L3 perpendicular to the first direction L1 and the second direction L2. It is observed that the first part 32 and the second part 34 extend in the same plane comprising the first direction L1 and the second direction L2.

[0037] In a first embodiment shown in Figure 5A, the intermediate part 36a comprises at least two segments 38, 40 extending along the third direction L3, a first segment 38 of said two segments extending along a first direction L3-1 of the third direction L3 and a second segment 40 extending along a second direction L3-2 of the third direction L3, the first direction L3-1 being opposite to the second direction L3-2. The first part 32 is therefore connected to a first segment 38 which is connected to the second segment 40, the latter being connected to the second part 34.

[0038] According to a more general formulation, the intermediate part 36a, 36b, 36c, 36d can comprise N segments arranged successively one after the other in a given direction of the first direction L1 so as to form one or more successive undulations. The number of segments can be even or odd. It is understood that the 2k+1 segments extend in a first direction L3-1 of the third direction L3 and that the 2k segments extend along a second direction L3-2 of the third direction L3. The ends of the segments are connected to each other by rounded portions 42 to facilitate the deformation of the intermediate part. The radius of curvature of said rounded portions 42 may be less than 0.2 mm, preferably less than 0.1 mm. There could be an even number of segments (Figures 5A and 5B) or an odd number of segments (Figures 5C and 5D).

[0039] The term "segment" should be interpreted as a portion connecting two elements and is not necessarily straight in cross-section along a plane comprising the first direction L1 and the third direction L3. More generally, the term segment should be understood as designating a portion that may be curved.

[0040] As shown in Figure 5B, the intermediate part 36b can exhibit symmetry about a plane comprising the second direction L2 and the third direction L3. It has an even number of segments, specifically four segments 44. In the case of Figure 5C, the lamella 30b has an axis of central symmetry about an axis extending along the second direction L2 and the third direction L3. It has an odd number of segments.

[0041] Although not shown in the figures, the lamella 30a, 30b, 30c, 30d could have a generatrix along the first direction and a director along a direction extending at least in the second direction. This director could be oriented strictly along the second direction L2 or extend partially along the second direction. The generatrix is ​​formed by the cutting line of the lamella 30a, 30b, 30c, 30d illustrated in Figure 5.

[0042] In the embodiment of figure 5A, the lamella 30a comprises only two segments 38, 40 of the same length and which are symmetrical to each other along a plane comprising the second direction L2 and the third direction L3. The two segments 38, 40 could still have different lengths.

[0043] The lamella 30a, 30b, 30c, 30d can have a substantially constant thickness from one end to the other along the first direction L1. The lamella 30a, 30b, 30c, 30d can be formed by successive deformation operations of an initially completely flat lamella.

[0044] In the embodiments of figures 5A, 5B and 5C, the lamella 30a, 30b, 30c could extend relative to the first part 32 and the second part 34 over a distance along the third direction L3 which could be identical or different.

[0045] Figure 5D illustrates an intermediate part 30d comprising two pairs of segments symmetric to each other with respect to a plane comprising the second direction L2 and the third direction L3, said two pairs of segments being connected to each other by a portion in C. The first pair of segments comprises a first segment 46 oriented along the first direction of the third direction L3 from the first part 32 and a second segment 48 oriented along the second direction of the third direction from the first segment.

[0046] The C-shaped portion provides additional flexibility to the sealing strip in the first and third directions without significantly increasing its size.

[0047] The first segment 46 may be shorter than the second segment 48. In another example, the first segment may be longer than the second segment. The second segment 48 comprises two successive portions: a first portion 48a substantially parallel to the first segment 46, and a second portion 48b that may cross the plane formed by the first direction L1 and the second direction L2 and includes the first part 32. In another configuration, the first portion 48a may cross the plane formed by the first direction L1 and the second direction L2 and includes the first part 32. In this configuration, the entire second portion 48b lies above said plane along the first direction of the third direction.

[0048] These two configurations allow the C portion and therefore the overall size to be positioned along the third direction L3 on one side or in a centered manner with respect to the plane formed by the first and second directions L1, L2 and including the first part 32. These possibilities facilitate the adaptation of the sealing strip to the geometry of the slots in which the sealing strips are inserted.

[0049] The second pair of segments 52, 54 may be identical to the first pair of segments and is symmetrical to the first pair of segments with respect to a plane comprising the second direction L2 and the third direction L3. In another variant, the two pairs of segments may not be identical if, for example, the sealing strip is to be inserted into asymmetrical slots.

[0050] The ends of the second segments 48 of each pair of segments are connected by a segment 50 having a C shape whose concave portion can be oriented along the second direction L3-2 of the third direction L3. The junctions of the segment 50 to the said ends of the second segments 48, 54 are made by rounded portions 42.

[0051] The first segment 46 of the first pair of segments and the first segment 52 of the second pair of segments can extend along the first direction L3-1 of the third direction L3 and extend towards each other along the first direction L1.

[0052] In this variant, the first segments of the first pair and the second pair of segments 46, 48 together define a circular arc with a radius of curvature RC1. In another variant, said first segments 46, 48 can extend along a circular arc which may be identical or different.

[0053] The C-shaped segment 50 can have a constant radius of curvature RC2. This radius of curvature RC2 can be between 40 and 60% of the radius of curvature RC1, and preferably about 50% of the radius of curvature RC1. Such radius ratios between circles C1 and C provide a good compromise between the flexibility and strength of the sealing strip.

[0054] The circle C1 defined by the first segment 46, 52 can be concentric with the circle defined by the C-shaped segment 50. This configuration allows for a further reduction in the bulk of the sealing strip in the first and third directions.

[0055] The intermediate part 36a, 36b, 36c, 36d could have a dimension along the third direction L3 between 1 and 4 mm and a dimension along the first direction L1 between 1 and 3 mm.

[0056] With regard to figure 5A, the height of the intermediate part can be substantially equal to its width.

[0057] With regard to figures 5B and 5C, the intermediate part can extend along the third direction L3 over a distance between 2 and 3 times the distance over which a complete undulation extends along the first direction L1. A undulation is formed by the equivalent of one wavelength.

[0058] With regard to figure 5D, the height of the intermediate part can be approximately equal to its width.

Claims

Demands

1. A sealing blade (30a, 30b, 30c, 30d) for a turbomachine turbine, in particular for a turbine wheel, extending along a first direction (L1) and a second direction (L2) substantially perpendicular to each other, comprising a first portion (32) and a second portion (34) connected to each other by an intermediate portion (36a, 36b, 36c, 36d) along the first direction, wherein the first portion (32) and the second portion (34) are substantially planar along the first direction (L1) and the second direction (L2), and wherein the intermediate portion (36a, 36b, 36c, 36d) is shaped to have less rigidity than the first portion (32) and the second portion (34) along a third direction (L3) perpendicular to the first direction (L1) and the second direction (L2).

2. Sealing strip according to claim 1, wherein the intermediate part (36a, 36b, 36c, 36d) comprises at least two segments (38, 40, 44) extending along the third direction (L3), a first segment (38, 44) of said two segments extending along a first direction of the third direction (L3) and a second segment extending along a second direction of the third direction (L3), the first direction being opposite to the second direction.

3. Lamella according to claim 1 or 2, wherein the first segment (38) and the second segment (40) are directly connected to each other.

4. Lamella according to claim 2 to 4, wherein the intermediate part (36a, 36b, 36c, 36d) comprises N segments arranged successively one after another so as to form one or more successive undulations.

5. Lamella according to any one of the preceding claims, wherein the lamella (36a, 36b, 36c, 36d) has a generatrix along the first direction and a director along a direction extending at least along the second direction.

6. Lamella according to the preceding claim, in which the director extends along the second direction.

7. Lamella according to any one of the preceding claims, wherein the lamella (30a, 30b, 30d) has a plane of symmetry extending along the second direction (L2) and the third direction (L3).

8. Lamella according to any one of claims 1 to 6, wherein the lamella (36c) has a central axis of symmetry along an axis extending along the second direction (L2) and the third direction (L3).

9. Lamella according to any one of the preceding claims, wherein it has a substantially constant thickness from one end to the other of the lamella along the first direction (L1).

10. A lamella according to any one of the preceding claims, wherein the intermediate portion (36d) comprises two pairs of segments symmetrical to each other with respect to a plan comprising the second direction (L2) and the third direction (L3), said two pairs of segments being connected to each other by a segment (50) at C.

11. A slat according to claim 9, wherein the C-shaped segment has a concavity oriented along the third direction.

12. A sectorized ring, in particular a turbine ring, comprising a plurality of sectors arranged circumferentially end to end and each having a slot at each circumferential end, a slat according to any one of the preceding claims being mounted in a slot of one sector and in a circumferentially opposite slot of a circumferentially adjacent sector.

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