US20140044537A1

US20140044537A1 - Gas turbine

Info

Publication number: US20140044537A1
Application number: US13/959,021
Authority: US
Inventors: Hans-Peter Hackenberg
Original assignee: MTU Aero Engines AG
Current assignee: MTU Aero Engines AG
Priority date: 2012-08-10
Filing date: 2013-08-05
Publication date: 2014-02-13
Also published as: ES2547340T3; EP2696039A1; EP2696039B1

Abstract

A gas turbine stage, in particular a low-pressure compressor stage, for a gas turbine, in particular an aircraft engine gas turbine having a guide vane assembly having at least one guide vane (1) having a radially inner guide vane root (1.1), on which a sealing ring element (2) is supported by a spoke-type centering that has an inner wall (1.2) and a circumferential groove (2.1, 2.2) receiving the same, the inner wall having at least one face (1.4) facing a groove inner surface of the circumferential groove and a flank (1.5) adjacent thereto and angled therefrom; a rounded portion, in particular a radius (R) being formed between the face and the flank.

Description

This claims the benefit of European Patent Application EP 12179978.7, filed Aug. 10, 2012 and hereby incorporated by reference herein.
The present invention relates to a gas turbine stage, in particular a low-pressure compressor stage having a guide vane assembly and a sealing ring element, to a gas turbine, in particular an aircraft engine gas turbine having one or a plurality of such gas turbine stages, as well as to a guide vane assembly and a sealing ring element for such a gas turbine.

BACKGROUND

PCT Patent Application No. WO 2002/090720 A1 describes a guide vane assembly on which a brush sealing ring is mounted via what is generally referred to as a spoke-type centering. Therefore, to avoid being unnecessarily redundant, reference is made to the disclosure of this prior publication in its entirety, and it is hereby expressly incorporated by reference in the disclosure of the present invention.
This type of spoke centering provides for an inner wall to engage from the one guide vane assembly and a sealing ring element into a circumferential groove of the other guide vane assembly and the sealing ring element. Along the lines of operation-internal practice, a developed view in the circumferential direction, respectively a plan view of the spoke-type centering shows that the inner wall has a rectangular cross section having two mutually opposing faces facing the groove inner surfaces of the circumferential groove and two flanks angled by 90° therefrom that merge integrally with one another at one edge.
If the guide vane assembly is subject to a torsional deformation, in particular if the guide vanes undergo radial torsion, especially due to pressure loading and/or temperature loading, this may cause one or two mutually diagonally opposing edges to abut against the groove inner surfaces. This may lead, in particular, to localized stress peaks and/or increased wear.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide an improved gas turbine.
The present invention provides a gas turbine, in particular an aircraft engine gas turbine having one or a plurality of gas turbine stages, in particular low-pressure compressor stages, which, in accordance with another aspect of the present invention, each have one guide vane assembly having one or a plurality of guide vanes having a radially inner guide vane root. In a further refinement, two or more guide vanes may be joined to one another, in particular integrally.
A sealing ring element is supported on the guide vane by a spoke-type centering that features an inner wall and a circumferential groove receiving the same. In this case, a circumferential groove is understood, in particular, to be a circumferentially extending depression, respectively recess that is delimited on both sides by parallel groove inner surfaces, in particular. A sealing ring element may be one part of a multipart, closed sealing ring. For the sake of brevity, a one-piece sealing ring is also generally described along the lines of the present invention as a sealing ring element.
The inner wall has one or a plurality of, in particular two mutually opposing, preferably parallel faces, which each face a groove inner surface of the circumferential groove and, particularly in an undeformed state, may be oriented, at least substantially, normally to an axial direction of the gas turbine stage. Adjacently thereto, in particular joining the same, the inner wall has one or a plurality of, in particular two mutually opposing, preferably parallel flanks, which are each angled relative to the adjacent faces, respectively form an angle therewith, that may preferably be greater than 75° and/or smaller than 105°.
In accordance with one aspect of the present invention, a rounded portion, in particular a radius is formed in each case between at least one of these faces and at least one of these flanks. In the present case, a rounded portion is understood, in particular, to be a singly or multiply, in particular convexly curved joining surface which, in particular, may have radially extending, straight generatices; it being possible in one further refinement for the rounded portion to be configured to be kink-free, respectively to have a continuous curvature.
In accordance with this aspect, instead of the previous in-plant, known edges, which can lead to localized stress peaks and/or increased wear, a rounded portion is formed between the face facing the groove inner surface and the flank adjacent thereto, making it possible to advantageously reduce any occurring stress and/or wear, particularly in the case of guide vane-torsion induced abutting of the inner wall obliquely against one or both groove inner surfaces.
As explained at the outset, the inner wall of the spoke-type centering may be joined, in particular integrally, to the guide vane root, and the circumferential groove may be formed on the sealing ring element. Conversely, the inner wall may likewise be joined, in particular integrally, to the sealing ring element, and the circumferential groove may be formed on the guide vane root. Accordingly, other aspects of the present invention relate to a guide vane assembly, respectively a sealing ring element for the gas turbine (stage) described here, having an inner wall joined thereto that is provided to be received in a circumferential groove to form a spoke-type centering of the sealing ring element on the guide vane assembly, the inner wall having at least one face facing a groove inner surface of the circumferential groove and a flank adjacent thereto and angled therefrom, and a rounded portion, in particular a radius being formed between the face and the flank. Therefore, these embodiments, in particular advantageous further refinements relate equally to such a guide vane assembly, respectively such a sealing ring element, a gas turbine stage and a gas turbine having such a spoke-type centering.
In one embodiment of the present invention, the inner wall has at least one radial groove for receiving a sliding element, in particular a sliding block connected to the circumferential groove, to provide a spoke-type centering.
In a further refinement of the embodiment, in accordance with which the rounded portion is a radius, respectively a constant curvature, this radius is at least 25%, in particular at least 30% of a width of the flank. A width of a flank is understood, in particular, to be the axial width thereof, respectively the wall thickness of the inner wall. In particular, the radius may be at least 0.5 mm, in particular at least 10 mm, and preferably at least 15 mm.
A rounded portion may be produced by master forming, especially it may be cast, in particular together with the inner wall, respectively the face(s) and flank(s) thereof. Additionally or alternatively, the rounded portion may preferably be formed and/or machined, respectively manufactured.
In accordance with one embodiment of the present invention, a rounded portion may be hardened, in particular by an appropriate thermal process and/or by application of a coating. In particular, this may hereby further reduce the wear in the region of the rounded portion.
The present invention is particularly advantageous for the spoke-type centering of a brush-type sealing ring element.
A guide-vane assembly may have a preferential direction for torsion that may result, for example, from an angle of attack and/or a profile of the guide vanes or the like. In the present case, this is understood, in particular, to be a torsional direction about a radial axis in which the guide vane(s) of the guide vane assembly are subject to twisting action during operation in response to increased through-flow and/or power of the gas turbine (stage). In one preferred embodiment, a rounded portion is then also or only provided, in particular at one end of the face(s) in the circumferential direction that is positioned against the adjacent groove inner surface in response to torsion in the preferential direction for torsion.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages and features will become apparent from the dependent claims and the exemplary embodiment. To this end, in a partially schematized form:

FIG. 1 shows a meridian section of a portion of a gas turbine having a gas turbine stage having a guide vane assembly in accordance with an embodiment of the present invention;

FIG. 2 shows the guide vane assembly of FIG. 1 in a perspective view; and

FIG. 3 shows a developed section, respectively a plan view in the radial direction of a spoke-type centering of the guide vane assembly of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 shows a meridian section of a portion of a gas turbine having a gas turbine stage having a guide vane assembly in accordance with one embodiment of the present invention. The guide vane assembly shown in a perspective view in FIG. 2 has a plurality of integrally interconnected guide vanes I having a common, radially inner guide vane root 1.1, from where a common inner wall 1.2 extends out from a side facing away from the guide vane blade (at the bottom in FIG. 1, 2) of guide vane root 1.1 radially inwardly (toward the bottom in FIG. 1, 2). A radial groove 1.3 is configured in inner wall 1.2.
Radially movably disposed therein is a sliding block that is connected to a circumferential groove having two sides 2.1, 2.2 that is configured in a brush sealing ring element 2. Brush sealing ring element 2 is hereby supported with spoke-type centering action on the guide vane assembly.
As is discernible in the circumferentially developed sectional view, respectively the plan view in FIG. 3 in the radial direction from radially outwardly to radially inwardly, inner wall 1.2, which is configured between the two sides 2.1, 2.2 of the circumferential groove of brush sealing ring element 2, features two parallel, plane axial faces 1.4, which, in the undeformed condition of guide vanes 3, are oriented normally to an axial direction of the gas turbine stage, i.e., extend vertically in FIG. 3. These two faces 1.4 are joined by two parallel, plane flanks 1.5 that are angled at right angles relative to faces 1.4.
A rounded portion in the form of a radius R is configured in each instance between the face that is forward facing relative to the flow direction (left in FIG. 3), and the face that is rearward facing relative to the flow direction (right in FIG. 3), and flank 1.5 at the bottom in FIG. 3.
If, as shown in FIG. 3, guide vane torsion causes face 1.4, which is forward facing relative to the flow direction, to make contact with groove inner surface of side 2.1, this radius R reduces the stress load and the wear. If, in response to guide vanes 3 being subject to even greater torsion, face 1.4, which is rearward facing relative to the flow direction, is additionally induced to make contact with groove inner surface of side 2.2, radius R there like reduces the stress load and the wear. In other words, this is the case if rounded portions R are provided in the circumferential direction in each instance at the end of faces 1.4 (above in the case of left face in FIG. 3; below in the case of right face in FIG. 3) that is positioned against the adjacent groove inner surface in response to torsion in the preferential direction for torsion (mathematically positive, respectively counterclockwise in FIG. 3).

LIST OF REFERENCE NUMERALS

1 guide vane
1.1 guide vane root
1.2 inner wall
1.3 radial groove
1.4 face
1.5 flank
2 (brushes) sealing ring element
2.1, 2.2 groove sides
3 guide vane
R radius/rounded portion

Claims

What is claimed is:

1. A gas turbine stage for a gas turbine, the gas turbine stage comprising:

a guide vane assembly having at least one guide vane having a radially inner guide vane root,

a sealing ring element supported on the guide vane assembly by a spoke-type centering that has an inner wall and a circumferential groove receiving the inner wall, the inner wall having at least one face facing a groove inner surface of the circumferential groove and a flank adjacent thereto and angled therefrom, wherein a rounded portion is formed between the face and the flank.

2. The gas turbine stage as recited in claim I wherein the rounded portion defines a radius R.

3. The gas turbine stage as recited in claim 1 wherein the inner wall is joined to the guide vane root, and the circumferential groove is formed on the sealing ring element.

4. The gas turbine stage as recited in claim 3 wherein the inner wall is joined integrally to the guide vane root.

5. The gas turbine stage as recited in claim 1 wherein the inner wall is joined to the sealing ring element, and the circumferential groove is formed on the guide vane root.

6. The gas turbine stage as recited in claim 5 wherein the inner wall is joined integrally to the sealing ring element.

7. The gas turbine stage as recited in claim 1 wherein the at least one guide vane includes at least two interconnected guide vanes having a common inner wall or circumferential groove.

8. The gas turbine stage as recited in claim 7 wherein the two interconnected guide vanes are integrally interconnected.

9. The gas turbine stage as recited in claim 1 wherein the inner wall has a radial groove for receiving a sliding element for forming the spoke-type centering.

10. The gas turbine stage as recited in claim 2 wherein the radius is at least 25% of a width of the flank.

11. The gas turbine stage as recited in claim 10 wherein the radius is at least 30% of the width of the flank.

12. The gas turbine stage as recited in claim 2 wherein the radius is at least 0.5 mm.

13. The gas turbine stage as recited in claim 12 wherein the radius is at least 10 mm.

14. The gas turbine stage as recited in claim 13 wherein the radius is at least 15 mm.

15. The gas turbine stage as recited in claim 1 wherein the rounded portion is produced by master forming, forming, or machining, or is hardened.

12. The gas turbine stage as recited in claim 1 wherein the sealing ring element is a brush sealing ring element.

13. The gas turbine stage as recited in claim 1 wherein the rounded portion is provided at one end of the face in the circumferential direction that is positioned against the adjacent groove inner surface in response to torsion in the preferential direction for torsion of the guide vane assembly.

14. A low-pressure compressor stage comprising the gas turbine stage as recited in claim 1.

15. A gas turbine comprising at least one gas turbine stage as recited in claim 1.

16. An aircraft engine comprising the gas turbine as recited in claim 15.

17. A guide vane assembly for a gas turbine, the guide vane assembly comprising at least one guide vane having a radially inner guide vane root and an inner wall joined thereto that is provided to be received in a circumferential groove of a sealing ring element of the gas turbine, the inner wall having at least one face facing a groove inner surface of the circumferential groove and a flank adjacent thereto and angled therefrom, and a rounded portion being formed between the face and the flank.

18. The guide vane assembly as recited in claim 17 wherein the rounded portion defines a radius R.

19. A sealing ring element for a gas turbine comprising an inner wall joined thereto that is provided to be received in a circumferential groove of a guide vane assembly of the gas turbine, the inner wall having at least one face facing a groove inner surface of the circumferential groove and a flank adjacent thereto and angled therefrom, and a rounded portion being formed between the face and the flank.

20. The sealing ring element as recited in claim 19 wherein the rounded portion defines a radius R.