EP2878769A1 - Gas turbine rotor blade with shroud sealing fins - Google Patents

Abstract

The present invention relates to a rotor blade for a turbine or compressor stage of a gas turbine, comprising a radially outer shroud (1) with a sealing rib arrangement having a first (3.1) and an adjacent second sealing rib (3.2), with the first sealing rib by a first Groove base (10) is connected to a peripheral region (13) of maximum radial height, which is arranged at a first circumferential position, wherein the sealing rib arrangement adjacent to the second sealing rib, the first sealing rib opposite third sealing rib (3.3), with the second sealing rib through a second groove bottom (20) is connected to a circumferential portion (23) of maximum radial height which is disposed at a second circumferential position different from the first circumferential position.

Description

The present invention relates to a blade for a turbine or compressor stage of a gas turbine, a gas turbine, in particular an aircraft engine gas turbine, with such a blade and a method for producing such a blade.

From the EP 2 402 559 A1 For example, a turbine blade having a radially outer shroud is known.

In particular, due to asymmetric overhangs of the shroud relative to the airfoil, centrifugal forces during operation induce stresses in the shroud that seek to distort it.

The EP 2 402 559 A1 therefore proposes, in a shroud pocket delimited circumferentially by two opposing z-shaped ribs, to arrange at least one reinforcing rib which extends substantially in the direction of the maximum or the principal axis of inertia of the blade or its radially outer portion.

However, such inclined in the pockets of the axis of rotation ribs are difficult to manufacture and may also be unfavorable in terms of flow.

An object of an embodiment of the present invention is to provide a gas turbine, in particular, to reduce at least one of the disadvantages explained above.

This object is achieved by a blade having the features of claim 1. Claims 8, 9 provide a gas turbine with a corresponding blade or a method for producing a corresponding blade under protection. Advantageous embodiments of the invention are the subject of the dependent claims. According to one aspect of the present invention, a gas turbine, in particular an aircraft engine gas turbine, one or more turbine stages and one or more compressor stages, each having one or more circumferentially distributed blades on. The blades can be detachably or non-detachably, in particular cohesively, connected to a rotor of the gas turbine or be formed integrally with this or be.

At least one of these blades has a radially outer shroud. In one embodiment, the shroud may be integrally formed with an airfoil of the blade, in particular ur- and / or reshaped, or materially connected, in particular welded or be. In one embodiment, the shroud has two edges which face each other in the circumferential direction. These are z-shaped in one embodiment. In one embodiment, the shrouds in the circumferential direction of adjacent blades touch each other along their edges.

On its radially outer, blade-side facing away from the outer surface, the shroud has a sealing rib arrangement with at least three sealing ribs, in particular a first sealing rib, one of these adjacent second sealing rib and one of the second sealing rib adjacent, the first sealing rib opposite third sealing rib. In a further development, the sealing rib arrangement can also have one or more further sealing ribs, in particular a fourth sealing rib adjacent to the third sealing rib, a fourth sealing rib adjacent to the second sealing rib, the fifth sealing rib opposite the third sealing rib, etc. In one embodiment, the first sealing rib is a leading edge closest sealing rib, in another embodiment, a trailing edge downstream seal rib.

In one embodiment, the sealing rib arrangement is opposite a housing sealing surface of the gas turbine.

The sealing ribs extend in one embodiment, at least substantially, in the circumferential direction. In one embodiment, different, in particular in the axial direction adjacent sealing ribs, different radial heights, in particular, to follow a divergent or convergent flow channel in which the blade is located.

Each two adjacent sealing ribs in the axial direction are each connected to each other by a groove bottom. In one embodiment, one or both sealing ribs, in particular in a, in particular rounded, edge pass into the groove base, which additionally or alternatively in at least one meridian section, in particular all meridian sections, in the axial direction may have an at least substantially constant radial height. In particular, the first and second sealing rib are connected by a groove bottom, which is referred to below as the first groove bottom, the second and third sealing rib by a groove bottom, which is hereinafter referred to as a second groove bottom. A groove bottom between a further sealing rib and one of these adjacent sealing rib, in particular a groove bottom, the third and one of the third sealing rib adjacent, the second sealing rib opposite fourth sealing rib or such a fourth sealing rib and the fourth sealing rib adjacent, the third sealing rib opposite fifth Sealing rib connects, is referred to in each case as another groove bottom.

At least the first and second groove base, in one embodiment also at least one, in particular all other groove bases, each have a region of maximum radial height in the circumferential direction. By radial height is meant in the present case in particular a distance to a rotational axis of the gas turbine or to a blade root of the blade.

If, in one embodiment, a groove base in the circumferential direction has two opposing flanks which merge into one another in an edge, in particular this edge can be a circumferential region of maximum radial height in the sense of the present invention. If, in another embodiment, a groove base in the circumferential direction has two opposing flanks which merge into two plateaus in two edges, then in particular this plateau can be a circumferential region of maximum radial height in the sense of the present invention.

A circumferential region of maximum radial height of a groove bottom is arranged in the circumferential direction at a circumferential position. If the circumferential area of maximum radial height is an edge in which two opposing flanks merge, the circumferential position of this edge may be the circumferential position of the circumferential area of maximum radial height. If the circumferential area of maximum radial height is a plateau into which two opposing flanks merge into two edges, in particular the circumferential position of the leading edge near edge, the leading edge distal edge, or the middle between both edges can be the circumferential position of the circumferential area of maximum radial height in the sense of the present invention Be invention.

Hereinafter, the circumferential position of the circumferential portion of the maximum radial height of the first groove bottom is referred to as the first circumferential position for discrimination, the circumferential position of the circumferential portion of the maximum radial height of the second groove bottom as the second circumferential position, the circumferential position of the circumferential portion of the maximum radial height of another groove base as a corresponding circumferential position.

In one aspect, the first and second circumferential positions are different. In other words, the circumferential area of the maximum radial height of the first groove bottom is offset from the circumferential area of the maximum radial height of the second groove base in the circumferential direction. In one embodiment, one or more further circumferential positions may be different from the first and / or second circumferential position, or a circumferential region of maximum radial height of at least one further groove base may be offset in the circumferential direction against the circumferential region of maximum radial height of the first and / or second groove base. In one embodiment, the circumferential positions of the circumferential areas of maximum radial height of all groove bottoms are different from one another or the circumferential regions of maximum radial height of all groove bottoms are offset from one another in the circumferential direction.

As a result, in particular in production and / or flow engineering advantageous manner, a stiffening rib within the sealing rib arrangement available are provided, which is inclined at least partially against the axis of rotation, in particular, to counteract a distortion of the shroud due to centrifugal forces.

This can be explained vividly by a very simple embodiment: if the first and second groove bottom are each formed like a ridge, wherein the ridges are circumferentially offset from each other, this results in a stiffening rib on both groove grounds, which diagonally intersects the second rib arranged therebetween and simply through each opposing, offset in the circumferential direction grinding of the first and second groove bottom can be made.

In one embodiment, a circumferential position of a circumferential area of maximum radial height of a leading edge remote groove bottom is offset from a circumferential position of a circumferential area of maximum radial height of a leading edge near groove bottom in the circumferential direction from a rear edge to a leading edge of the blade. In particular, in one embodiment, the circumferential region of the maximum radial height of the second, more downstream groove base relative to the peripheral region of maximum radial height of the first upstream groove base may be circumferentially offset to a leading edge of the rotor blade. As a result, in one embodiment, advantageously, those corners of the shroud which are less supported by the airfoil can be more strongly supported by the diagonal bracing rib in the rib assembly.

In particular, additionally or alternatively, the circumferential areas of maximum radial height of three or more, in particular all adjacent groove bases, at least substantially, lie on a straight line. In other words, the peripheral portions of the maximum radial height may be circumferentially offset from each other so as to form a continuous diagonal rib crossing the peripheral ribs of the rib assembly.

In one embodiment, one or more, in particular all groove bases of the sealing rib arrangement each have a first flank and a second flank opposite thereto. The first flank increases in the circumferential direction to the peripheral region of maximum radial height, the second edge decreases in the circumferential direction from the peripheral region of maximum radial height starting from. In one embodiment, the first and second flanks may merge into one another, in particular rounded edges, or transition into two, in particular rounded, edges into a plateau of at least substantially constant radial height, as explained above.

The first flank may in particular rise from a first edge of the shroud, the second flank additionally or alternatively fall down to a second edge of the shroud opposite the first edge in the circumferential direction. As a result, in one embodiment, the processing, in particular the entry or exit of a tool in or out of the groove can be improved.

Additionally or alternatively, in one embodiment, the radial height of the first and / or second edge in the circumferential direction monotonically, in particular strictly monotone, change, in other words, the first edge, in particular from the first edge, to the peripheral region of maximum radial height monotone, in particular increase strictly monotonically and / or the second edge of the peripheral region of maximum radial height, in particular down to the second edge, monotonically, in particular strictly monotonically decrease. In particular, the first and / or second flank may be linear or straight in the circumferential direction. As a result, machining, in particular a tool guide, can be improved in one embodiment.

As already explained above, the groove bottoms are circumferentially offset from each other peripheral areas maximum radial height in particular for machining, in particular by machining with geometrically undefined cutting edge, preferably grinding, honing, lapping and / or jets. Additionally or alternatively, a groove bottom in one embodiment can also be contoured by machining with a geometrically determined cutting edge, preferably filing, milling and / or sawing, by, in particular thermal and / or electrochemical, ablation, in particular die sinking, and / or Archetypes, in particular casting.

Fig. 1A

ein Deckband einer Laufschaufel einer Gasturbine nach einer Ausführung der vorliegenden Erfindung in einer Draufsicht in radialer Richtung;

Fig. 1B-1D

Schnitte längs der Linien B-B (Fig. 1B), C-C (Fig. 1C) bzw. D-D (Fig. 1D) in Fig. 1A; und

Fig. 2B-2D

Schnitte längs der Linien B-B (Fig. 2B), C-C (Fig. 2C) bzw. D-D (Fig. 2D) in Fig. 1A für eine alternative Ausführung der vorliegenden Erfindung.

Further advantageous developments of the present invention will become apparent from the dependent claims and the following description of preferred embodiments. This shows, partially schematized:

Fig. 1A

a shroud of a rotor of a gas turbine according to an embodiment of the present invention in a plan view in the radial direction;

Fig. 1B-1D

Sections along the lines BB ( Fig. 1B ), CC ( Fig. 1C ) or DD ( Fig. 1D ) in Fig. 1A ; and

Fig. 2B-2D

Sections along the lines BB ( Fig. 2B ), CC ( Fig. 2C ) or DD ( Fig. 2D ) in Fig. 1A for an alternative embodiment of the present invention.

Fig. 1A shows in a plan view in the radial direction from the outside a shroud 1 of a blade of a turbine stages of an aircraft engine gas turbine according to an embodiment of the present invention, the Fig. 1B to 1D Sections along the lines BB ( Fig. 1B ), CC ( Fig. 1C ) or DD ( Fig. 1D ) in Fig. 1A ,

The radially outer shroud is formed integrally with a blade 2 of the blade, which in Fig. 1B to 1D partially shown. It has two edges (top, bottom in Fig. 1 ), which in the circumferential direction (vertically in Fig. 1 ) are opposite and Z-shaped.

On its radially outer, blade-side facing away lateral surface (right in Fig. 1B to 1D ), the shroud has a sealing rib arrangement with a first, front edge next or upstream (left in Fig. 1A ) Sealing rib 3.1, one of these adjacent second sealing rib 3.2, one of the second sealing rib adjacent, the first sealing rib opposite third sealing rib 3.3 and the third sealing rib adjacent, the second sealing rib opposite another, hinterkantennächste or strömungsabwärtigste (right in Fig. 1A ) Sealing rib 3.4. The sealing ribs extend in the circumferential direction (vertically in Fig. 1 ).

The first and second sealing rib are connected by a first groove bottom 10, the second and third sealing rib by a second groove bottom 20, the third and further sealing rib by a further groove bottom 30th

The groove bottoms each have a first flank 11, 21 and 31, and a second flank 12, 22 and 32, which is in opposite directions for this purpose. The first flank increases in the circumferential direction (from top to bottom in Fig. 1B to 1D ) from a first edge of the shroud (at the top of FIG Fig. 1 ) linearly to an edge 13, 23 and 33, respectively, in which it merges into the second flank, which in opposite directions up to a second edge of the shroud opposite the first edge in the circumferential direction (bottom in FIG Fig. 1 ) decreases linearly. Thus, these edges 13, 23, 33 each form a circumferential region of maximum radial height of the respective groove base 10, 20 and 30, respectively.

These edges or peripheral regions of maximum radial height 13, 23 and 33 of the first, second and further groove base are offset from each other in the circumferential direction, as shown in particular the synopsis of the sections 1B, 1C and 1D.

Here, the second circumferential position of the peripheral portion 23 of the second groove bottom is against the first circumferential position of the peripheral portion 13 of the leading edge next groove base in the circumferential direction from a rear edge to a leading edge of the blade (from top to bottom in FIG Fig. 1 ), as shown in particular by the synopsis of sections 1B and 1C.

The further circumferential position of the further peripheral region 33 of the front edge remote groove bottom 30 is offset in the same way against the second circumferential position of the peripheral region 23 of the groove base in the circumferential direction, as shown in particular by the synopsis of the sections 1C and 1D. As a result, the circumferential areas of maximum radial height 13, 23 and 33 of the three adjacent groove bases 10, 20 and 30 lie on a straight line.

This results in a stiffening rib V on the Nutgründen 10, 20 and 30, which intersects the ribs arranged therebetween 3.2, 3.3 diagonally and simply by each opposing, offset in the circumferential direction grinding the groove bases can be made.

Fig. 2B to 2D show in Fig. 1B to 1D Similarly, sections through a blade according to an alternative embodiment of the present invention, the a plan view in the radial direction from the outside Fig. 1A equivalent. Corresponding elements are denoted by identical reference numerals, so that reference is made to the above description and will be discussed below only the differences.

In the execution of Fig. 2 go the first and second flanks 11, 12; 21, 22 and 31, 32 in each case in two edges in a plateau 13, 23 and 33 constant, maximum radial height, which thus each forms the peripheral region of maximum radial height in the sense of the present invention. Its circumferential position may, in particular, the circumferential position of the front edge closer (in Fig. 2 lower edge), the leading edge farther edge (in Fig. 2 above) or the middle between both edges.

Again, the second circumferential position of the peripheral portion 23 of the second groove bottom is against the first circumferential position of the peripheral portion 13 of the leading edge nearest groove bottom in the circumferential direction from a rear edge to a leading edge of the blade (from top to bottom in FIG Fig. 2 ), as shown in particular by the synopsis of sections 2B and 2C. The further circumferential position of the further peripheral region 33 of the front edge remote groove bottom 30 is offset in the same way against the second circumferential position of the circumferential region 23 of the groove base in the circumferential direction, as shown in particular the synopsis of the sections 2C and 2D. As a result, the circumferential areas of maximum radial height 13, 23 and 33 of the three adjacent groove bottoms 10, 20 and 30 are again on a straight line.

This results again in a stiffening rib on the Nutgründen 10, 20 and 30, which intersects the ribs arranged therebetween 3.2, 3.3 diagonal and are produced for example by die sinking, electro-chemical removal or by casting can. While this diagonal stiffening rib in the execution of the Fig. 1 However, it is formed roof ridge-like, it has in the execution of Fig. 2 a plateau up.

Although exemplary embodiments have been explained in the foregoing description, it should be understood that a variety of modifications are possible. It should also be noted that the exemplary embodiments are merely examples that are not intended to limit the scope, applications and construction in any way. Rather, the expert is given by the preceding description, a guide for the implementation of at least one exemplary embodiment, with various changes, in particular with regard to the function and arrangement of the components described, can be made without departing from the scope, as it turns out according to the claims and these equivalent combinations of features.

Reference numeral List

1

shroud

2

airfoil

3.1

first rib

3.2

second rib

3.3

third rib

3.4

another rib

10

first groove bottom

20

second groove bottom

30

further groove bottom

11; 21; 31

first flank

12; 22; 32

second flank

13; 23; 33

Edge / plateau (circumferential area of maximum radial height)

V

stiffening rib

Claims (9)

Blade for a turbine or compressor stage of a gas turbine, comprising a radially outer shroud (1) with a sealing rib arrangement having a first (3.1) and an adjacent second sealing rib (3.2) with the first sealing rib by a first groove bottom (10) a peripheral portion (13) of maximum radial height connected at a first circumferential position;
characterized in that
the sealing rib assembly has a third sealing rib (3.3) adjacent to the first sealing rib and connected to the second sealing rib by a second groove bottom (20) having a circumferential portion (23) of maximum radial height which is at one of the first circumferential position different second circumferential position is arranged. Blade according to the preceding claim, characterized in that the sealing rib arrangement has at least one further sealing rib (3.4) which is connected to an adjacent sealing rib (3.3) by a further groove base (30) with a peripheral region (33) of maximum radial height a further, in particular from the first and / or second circumferential position different circumferential position is arranged. A moving blade according to any one of the preceding claims, characterized in that a circumferential position of a circumferential portion (23; 33) of maximum radial height of a forward edge remote groove bottom against a circumferential position of a peripheral portion (13; 23) maximum radial height of a leading edge near groove bottom in the circumferential direction from a rear to a Front edge of the blade is offset towards. Blade according to one of the preceding claims, characterized in that the peripheral regions (13, 23, 33) of the maximum radial height of at least three adjacent groove bottoms lie, at least substantially, on a straight line. Blade according to one of the preceding claims, characterized in that at least one groove bottom of the sealing rib arrangement a first flank (11; 21; 31), in the circumferential direction, in particular from a first edge of the shroud, to the peripheral region of maximum radial height, in particular monotonically has, and in particular an opposite second flank (12; 22; 32) which decreases in the circumferential direction of the peripheral region of maximum radial height, in particular to a first edge in the circumferential direction opposite the second edge of the shroud, in particular monotonically decreases. A moving blade according to the preceding claim, characterized in that the first and second flanks merge into one another in one edge (13; 23; 33) or merge into two edges in a plateau (13; 23; 33). Blade according to one of the preceding claims, characterized in that at least one groove bottom of the sealing rib arrangement, at least partially, by machining with geometrically undefined cutting edge, in particular by grinding, by, in particular thermal and / or electrochemical, ablation, in particular Senkerodieren, and / or Archetypes, in particular casting, is contoured. Gas turbine, in particular aircraft engine gas turbine, with at least one turbine and / or compressor stage with at least one blade according to one of the preceding claims. Method for producing a moving blade according to one of the preceding claims, characterized in that at least one groove bottom of the sealing rib arrangement, at least partially, by machining with geometrically undefined cutting edge, in particular by grinding, by, in particular thermal and / or electrochemical, ablation, in particular Senkerodieren , and / or prototypes, in particular casting, is contoured.

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