Inner ring for a turbomachine, vane ring with an inner ring, turbomachine and method of making an inner ring

Abstract

The invention relates to an inner ring for a guide vane assembly for mounting adjustable guide vanes of a turbomachine, of a compressor stage or turbine stage of a gas turbine, a guide vane assembly for a turbomachine having an inner ring, a turbomachine having an inner ring, and a method for producing an inner ring, wherein the inner ring has a plurality of guide vane bearing mounts, which are each arranged spaced apart in the peripheral direction, recesses, which are each formed for receiving a bearing element, a bearing journal, of a guide vane, wherein, between at least two adjacent guide vane bearing mounts, the inner ring has at least one depression with a wall thickness in a radial direction that is reduced in comparison to a region that abuts the depression and is outside of the depression.

Claims

1. An inner ring for a guide vane assembly for mounting adjustable guide vanes of a turbomachine, of a compressor stage or turbine stage of a gas turbine, wherein the inner ring has a plurality of guide vane bearing mounts, which are each arranged spaced apart from one another in a peripheral direction, recesses, which are each formed for receiving a bearing element, a bearing journal, of a guide vane, wherein, between at least two adjacent guide vane bearing mounts, the inner ring has at least one depression with a wall thickness that is reduced in a radial inward direction from a radial outermost surface of the inner ring in comparison to a region that abuts the depression and is outside of the depression, wherein, in relation to an axis of rotation of the turbomachine in a functionally installed state of the inner ring in a turbomachine, the depression has a larger extension in an axial direction than in the peripheral direction, and the region that abuts the depression is arranged at a radial height that is the same as the radial outermost surface of the inner ring and the region extends between the at least one depression and the recess defining a wall.

2. The inner ring according to claim 1, wherein the depression are a plurality of depressions that are each arranged on a side of the inner ring that faces away from the guide vanes, wherein the plurality of depressions are distributed, at least essentially equidistantly.

3. The inner ring according to claim 1, wherein at least between two adjacent guide vane bearing mounts or adjacent groups of guide vane bearing mounts, exactly one depression is provided in each case.

4. The inner ring according to claim 1, wherein, in relation to a functionally installed state of the inner ring in a turbomachine, at least one depression is arranged on a side of the inner ring that faces away from the guide vanes, in an inner-lying surface of the inner ring in a radial direction, in an inner shell surface of the inner ring.

5. The inner ring according to claim 1, wherein a peripheral contour of at least one depression extends at least partially parallel to a peripheral contour of an adjacent recess, in a region of the peripheral contour that extends in the axial direction of the inner ring, in relation to a functionally installed state in a turbomachine, wherein the peripheral contour extends at least partially parallel to the peripheral contours of both adjacent recesses.

6. The inner ring according to claim 1, wherein a peripheral contour of at least one depression extends at least partially parallel to a contour of the inner ring in the peripheral direction of the inner ring, in a region of the peripheral contour that extends essentially in the peripheral direction of the inner ring, in relation to a functionally installed state in a turbomachine.

7. The inner ring according to claim 1, wherein at least one depression has a bone-shaped, bone-like-shaped, hourglass-shaped, or hourglass-like-shaped peripheral contour, in relation to a projection of a peripheral contour of the depression in a tangential plane of the inner ring.

8. The inner ring according to claim 1, wherein at least one depression has a peripheral contour that is completely closed or is open at least at one axial end.

9. The inner ring according to claim 1, wherein at least one depression has a bottom surface, wherein the depression has a constant depth at least partially, at least in the region of the bottom surface, over the entire bottom surface.

10. The inner ring according to claim 1, wherein the inner ring is formed in multiple parts.

11. The inner ring according to claim 1, wherein at least one depression is introduced by a cutting manufacturing method into the inner ring by machining.

12. The inner ring according to claim 1, wherein a compressor stage or turbine stage of a gas turbine, has adjustable guide vanes which are mounted at the inner ring.

13. The inner ring according to claim 12, wherein a guide vane assembly has a seal carrier or a seal carrier segment, wherein the seal carrier or the seal carrier segment is arranged at the inner ring on the side facing away from the guide vanes and covers at least one depression that is arranged in a surface facing away from the guide vanes at least partially.

14. The inner ring according to claim 1, wherein the inner ring is configured and arranged in a turbomachine with at least a compressor stage or turbine stage.

15. The inner ring according to claim 1, wherein at least one depression is produced by milling.

Description

BRIEF DESCRIPTION OF THE DRAWING FIGURES

(1) Additional advantageous enhancements of the present invention ensue from the dependent claims and the following description of preferred embodiments. Shown for this purpose in a partially schematic manner are:

(2) FIG. 1 shows a cutout of a guide vane assembly segment of a turbomachine, which is designed as a compressor and is known from prior art, in the region of an inner ring in a side view,

(3) FIG. 2 shows a cutout of the guide vane assembly segment from FIG. 1 in a perspective illustration,

(4) FIG. 3 shows a cutout of a first exemplary embodiment of an inner ring segment of an inner ring according to the invention in a perspective illustration in a view from radially inward,

(5) FIG. 4 shows the inner ring segment from FIG. 3 in a view from radially inward,

(6) FIG. 5 shows a cutout of an inner ring segment of a second exemplary embodiment of an inner ring according to the invention in a perspective illustration,

(7) FIG. 6 shows the inner ring segment from FIG. 5 in another perspective illustration, and

(8) FIG. 7 shows a cutout of a third exemplary embodiment of an inner ring according to the invention in a perspective illustration.

DESCRIPTION OF THE INVENTION

(9) For better understanding of the invention, FIG. 1 shows a cutout of a generic guide vane assembly 1 of a turbomachine, which is known from prior art and has an inner ring segment 20, in the region of the inner ring segment 20 in a side view.

(10) The guide vanes 10 are mounted on the inner ring segment 20 in a way that is known from prior art, whereby, to this end, the inner ring segment 20 has guide vane bearing mounts 24, which are arranged uniformly distributed in the peripheral direction and are designed, in particular, as through openings, wherein the guide vanes 10 are joined to the inner ring segment 20 via bearing journals 11 that extend in a radial direction y and are supported at the inner ring segment 20 in a radial direction.

(11) In this case, the guide vanes 10 are adjustably formed and joined to the inner ring segment 20 so as to rotate around a longitudinal axis L. For minimization of the friction between the bearing journal 11 and the inner ring segment 20, a bushing 25 is introduced into the through hole for the guide vane bearing mount 24 in each case.

(12) For sealing with respect to the rotatably mounted rotor 30 of the turbomachine, the guide vane assembly 1 further has a seal carrier segment 21 that is fastened to the inner ring segment 20 on a side facing away from the guide vanes 10, wherein the seal carrier segment 21 is likewise arranged in a known way at the inner ring segment 20, wherein in this case, in particular for promoting a high sealing effect, the guide vane bearing mounts 24, which are formed as through holes, are covered by the seal carrier segment 21 on a side of the inner ring that faces away from the guide vanes 10.

(13) For a further improvement of the sealing effect, a sealing structure 22, in particular a honeycomb-shaped sealing structure 22, is provided at a radial inner side of the seal carrier segment 21 and interacts with so-called sealing fins 31, which are fastened at the rotor, extend outward in a radial direction from the rotor, and seal a gap between guide vane assembly or guide vane assembly segment 1, which is in fixed arrangement at the housing, and the rotatably mounted rotor 30 of the turbomachine in order to reduce flow losses due to leakages during flow around the guide vane 10 and, in particular, to bring about a reduction of the volume flows in the region of the guide vanes 10.

(14) The guide vane assembly segment 1 is hereby a part of a guide vane assembly that is divided in the peripheral direction into a plurality of guide vane assembly segments 1, wherein each guide vane assembly segment 1 has an inner ring segment 20 and a corresponding seal carrier segment 21. For connection of the individual guide vane assembly segments to one another in the peripheral direction, in particular for connection of the individual inner ring segments 20 to one another in the peripheral direction, each inner ring segment 20 has a connecting journal 23 at one of its front sides in the peripheral direction and, at the other front side, a recess that is formed correspondingly to the connecting journal 23 and is not illustrated here.

(15) FIG. 2 shows a cutout of the guide vane assembly segment from FIG. 1 in a perspective illustration, wherein, in this illustration, in particular the connecting journals 23 at the front side of the inner ring segment 20, the guide vane bearing mounts 24 formed as through holes, and the bushings 25 arranged in the through holes for the guide vane bearing mounts 24 can be seen especially well.

(16) During operation of the turbomachine, working fluid flows around the guide vanes 10 in the axial direction x and, in consequence thereof, the inner ring or the individual inner ring segments 20 heats up or heat up, whereby the inner ring segments 20 hereby heat up more rapidly on their outer side owing to the working fluid that directly flows by than at their inner side, which faces away from the guide vanes 10 and faces the seal carrier segment 21, as a result of which a widening of gaps, in particular a widening of sealing gaps, occurs and, in consequence thereof, leakages occur.

(17) FIG. 3 shows a cutout of a first exemplary embodiment of an inner ring segment 120 of a multipart inner ring according to the invention, which is divided in the peripheral direction, in a perspective illustration in a view from radially inward and FIG. 4 shows the inner ring segment 120 from FIG. 3 in a view from radially inward. The inner ring segment 120 of an inner ring formed in accordance with the invention, illustrated in FIG. 3 and FIG. 4, has a plurality of depressions 126, which are only indicated in the illustration and which, in particular, are arranged uniformly distributed in the peripheral direction and are introduced into an inner shell surface of the inner ring segment 120, wherein, in particular, exactly one depression is arranged between every two adjacent guide vane bearing mounts 124 of a pair of guide vane bearing mounts 124.

(18) The depressions 126 in accordance with the invention result in a local reduction in the cross-sectional area of the inner ring segment 120 and, in particular, in a local reduction in the wall thickness of the inner ring segment 120. In this way, it is advantageously possible to achieve an improved, transient heating behavior of the inner ring segment 120 and, accordingly, of the entire inner ring, because less material of the inner ring needs to be heated. In particular, it is possible to achieve an improved, transient temperature profile in a radial direction y, in particular a temperature profile with a smaller thermal gradient in a radial direction y.

(19) In accordance with the invention, the depressions 126 hereby have a larger extension in the axial direction x than in the peripheral direction. This results in an especially advantageous thermal behavior of the inner ring or of the inner ring segments 120 during operation of an associated turbomachine.

(20) In this exemplary embodiment, the depressions 126 hereby each have a closed peripheral contour 127, wherein the peripheral contour in the region of their axial extension 127A and 127B extends parallel in each case, that is, with a constant separation, to a peripheral contour of the guide vane bearing mounts 124 and, in its segments 127C and 127D, which extend in the peripheral direction, extends parallel in each case to a peripheral contour of the inner ring segment 120.

(21) The depressions 126 hereby have, in particular, an essentially bone-shaped peripheral contour 127 in relation to a projection in a tangential plane of the inner ring segment 120. Furthermore, the depressions 126 are formed symmetrically in the axial direction and extend, in particular locally, between two abutting and in particular adjacent guide vane bearing mounts 124 nearly completely over the region between these guide vane bearing mounts 124.

(22) FIG. 5 shows a cutout of a second inner ring segment 220 of a second exemplary embodiment of an inner ring according to the invention in a perspective illustration. FIG. 6 shows the inner ring segment 220 from FIG. 5 in another perspective illustration, wherein this exemplary embodiment of an inner ring segment 220 of an inner ring according to the invention is part of an inner ring than is divided both in the peripheral direction and in the axial direction x, wherein a subplane hereby extends in the axial direction centrally all the way through the guide vane bearing mounts 224 and the depressions 226.

(23) In this illustration, the depressions 126 in accordance with the invention, which likewise have an essentially bone-shaped peripheral contour that, in this case, however, is not identified in greater detail, can be seen especially well. The depressions 226 each have a bottom surface 228, wherein the individual depressions 226 in this exemplary embodiment each have a constant depth T over nearly the entire bottom surface 228 and thus a constant, local wall thickness in the region of the depressions 226.

(24) FIG. 7 shows a cutout of a third exemplary embodiment of an inner ring according to the invention in a perspective illustration, wherein, in this exemplary embodiment, on account of the large number and, in particular, tighter arrangement of the guide vane bearing mounts 324, the depressions 326 extend over a smaller surface, but are otherwise formed similarly to the previously described exemplary embodiments.

(25) All of the above-described exemplary embodiments of inner rings according to the invention share in common the fact that, in relation to a functionally installed state of the inner ring segments 120, 220, 320 or the associated inner rings, the depressions 126, 226, 326 are each arranged on a side of the inner ring that faces away from the guide vanes and, in particular, in an inner shell surface of the inner ring. Furthermore, all depressions 126, 226, 326 are each introduced by machining into the inner ring segments 120, 220, 320, in particular by milling.

(26) It has been found that an embodiment of the depressions 126, 226, 326 of this kind enables an especially advantageous heating behavior of the inner ring segments 120, 220, 320 and, accordingly, of the associated inner ring to be achieved and, in particular, a heating behavior of the respective inner ring that is improved in regard to the “cording effect” and, in particular, a heating behavior that reduces the “cording effect.” In consequence thereof, smaller leakages occur and this, in turn, has an advantageous effect on the efficiency and the specific fuel consumption of the compressor.

(27) Furthermore, it is possible in this way, namely, in particular by means of the previously described depressions 126, 226, 326, to achieve a bending stiffness that is reduced by about 15% in comparison to a comparable inner ring without depressions, as a result of which a further improvement of the “cording effect” can be achieved.

(28) Furthermore, the depressions 126, 226, 326 lead to an advantageous reduction in the weight of the inner ring and, accordingly, also to a reduction in the weight of the turbomachine.

(29) It is noted that the exemplary embodiments are merely examples, which are not intended to limit the protective scope, the applications, and the structure in any way. Instead, the above description affords the person skilled in the art a guide for the implementation of at least one exemplary embodiment, with it being possible to make diverse modifications, in particular in regard to the function and arrangement of the described component parts, without leaving the protective scope as ensues from the claims and the combinations of features equivalent thereto.