EP2818639B1 - Turbomachine rotor blade and corresponding turbomachine - Google Patents

Description

The present invention relates to a blade for a turbomachine and a turbomachine, in particular a gas turbine, with such a blade.

From the DE 10 2009 007 664 A1 For example, a blade for a turbomachine with a flow deflecting blade, a blade root for attachment to a rotor of the turbomachine, an inner platform between the blade and the blade root, and a pocket defined by two axially spaced walls extending away from the blade Side of the platform to the blade root out. These walls are offset with respect to a blade root edge in the direction of a radial longitudinal axis in order to improve the mechanical stress. The pocket-facing outer sides of these walls are circumferentially parallel.

From the US 4,595,340 Also, a blade having a circumferentially inwardly tapered pocket between an inner platform and a blade root is known to improve mechanical stress. The pocket-facing outer sides are also circumferentially parallel.

By inclined, tapered inner and peripheral parallel outer sides results in an increasing circumferential wall thickness towards the bottom of the bag. If two such pockets are arranged opposite each other in the circumferential direction, a material accumulation in the area of the blade leaf results in particular.

Other blades are from the documents GB1062170A . EP2586967A2 known. A blade according to the preamble of claim 1 is in the document US5924699A disclosed.

An object of an embodiment of the present invention is to provide an improved turbomachine.

This object is achieved by a blade having the features of claim 1. Claim 8 protects a turbomachine with such a blade under protection. Advantageous embodiments of the invention are the subject of the dependent claims.

A blade for a turbomachine according to one aspect of the present invention includes a flow deflecting blade having a pressure side, a suction side, leading and trailing edges (with respect to a flow direction in operation of the turbomachine).

A blade root for fastening the blade to a rotor of the turbomachine is connected to the blade leaf, in particular integrally or integrally. The blade root can in particular be designed as a so-called fir tree root and have one or more ribs, which engage behind respective undercuts of a groove in the rotor and thus fix the rotor blade, in particular radially, on the rotor.

Between the airfoil and the blade root is arranged a (in the mounted state radially inner) platform which defines a flow channel for a working medium of the turbomachine radially inward. Directional data such as axial, radial and circumferential direction generally relate in particular to the mounting position of the blade in the turbomachine.

In one embodiment, the inner platform has one or two opposing axial flanges to form a labyrinth seal with adjacent baffles.

In each case a pocket is arranged on both circumferentially opposite sides of the blade. At least one of them is defined in the axial direction by two axially spaced walls, which extend from the blade side facing away from the platform to the blade root and radially inward and are referred to below for compact representation as the first and second wall. The first wall may be an upstream or downstream wall (relative to a flow direction during operation of the turbomachine).

In the radial direction, the outside of the platform facing away from the blade on the outside limits the pocket; radially inward, the rotor can limit the pocket in the mounted state. The bag is in one embodiment in the circumferential direction on one side open or blind hole-like design, with a common Between wall in the circumferential direction opposite pockets of a blade from one another can limit or limit. Mutually facing pockets of adjacent blades, particularly the faces of their first and second walls and inner platforms, may contact one another in an embodiment such that their walls have two, at least substantially, closed, axially spaced sealing rings or flanges between the rotor and the inner Form platform ring.

According to one aspect of the present invention, at least the first wall of one or two opposing pockets of the blade each have a pocket-facing outer surface or surface, in one or more, preferably - at least substantially - all cross-sections perpendicular to a radial longitudinal axis of the blade in Viewed circumferential direction of the blade away from the outside or away from the bag. In other words, the outer side of the first wall diverges as it progresses in the circumferential direction on an adjacent blade or on an end face of the pocket or wall in the circumferential direction in the axial direction. Accordingly, the outer side converges or tapers from an end face of the first wall in the circumferential direction onto the blade towards axially inward direction or towards the pocket.

In this way, an increase in material due to a tapered pocket can be reduced, which can be advantageous in particular for the presentation of a draft angle.

In one embodiment, the second, axially opposite wall can also have an outer side facing away from the pocket, which is inclined in one or more, preferably - at least substantially - all cross sections perpendicular to the radial longitudinal axis in the circumferential direction away from the blade outwardly or in progression in Circumferential direction diverges on an adjacent blade or on an end face of the pocket or wall in the circumferential direction in the axial direction.

In another embodiment, however, the outer side of the second wall is, at least substantially, aligned in the circumferential direction or circumferentially parallel. In this way, in one embodiment, an advantageous Entformungsschräge, at least substantially provided by the first wall, while the second walls form a, at least substantially, circumferentially parallel sealing ring.

If the blade has two pockets facing each other in the circumferential direction, the outer sides of the first walls can be inclined to one another in a V-like manner.

The outside of the first wall is, at least substantially, parallel to an inside or surface of the first wall. Additionally or alternatively, the outside of the second wall may be, at least substantially, parallel to the inside of the second wall. This can be particularly advantageous in terms of manufacturing and / or loading technology. Additionally or alternatively, in one embodiment, a material accumulation due to a Entformungsschräge be minimized.

The first and / or second wall can be seen in the radial direction to be arched axially towards the pocket, in particular parabolic, as shown in the DE 10 2009 007 664 A1 is explained.

In a further development, the first wall is seen in the radial direction, in particular parabolic, arched axially to the bag, wherein its outer side facing away from the pocket in at least one cross section perpendicular to the radial longitudinal axis in a radially outer half and in at least one cross section perpendicular to the radial longitudinal axis in a radially inner Half is inclined in each case outwards or diverges to an open end side of the pocket in the circumferential direction in the axial direction.

An outwardly inclined outer side may, in at least one cross-section perpendicular to the radial longitudinal axis of the blade, in particular uniform, be curved, preferably strictly concave. Similarly, an outwardly inclined outside in at least one cross section perpendicular to the radial longitudinal axis of the blade, at least substantially, be straight. In one embodiment, a tangential plane to the outside in at least one cross section perpendicular to the radial longitudinal axis of the blade with the circumferential direction forms an angle which is at least 5 °, in particular at least 10 °, and / or at most 45 °, in particular at most 30 °.

In one embodiment, at least the pocket, in a further development also the blade leaf integrally formed therewith and / or the blade root integrally formed therewith, is formed in a particular way cast, and / or formed, in particular forged. Due to the inclined outer side (s), demoulding slopes for demolding the pocket from a casting mold or for executing a forming tool can be represented in one embodiment with a reduced material accumulation.

Advantageously, a blade according to the invention is used in a turbine or compressor stage of a gas turbine, in particular of an aircraft engine. Accordingly, a turbomachine, in particular a gas turbine, preferably an aircraft engine, according to one aspect of the present invention, a rotor and one or more of the above-described blades, which are fixed by means of their blade roots on the rotor, in particular form-fitting and / or releasably.

Fig. 1

einen Teil einer Laufschaufel einer Gasturbine nach einer Ausführung der vorliegenden Erfindung in perspektivischer Ansicht; und

Fig. 2

einen Querschnitt senkrecht zu einer radialen Längsachse der in Fig. 1 gezeigten Laufschaufel.

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. 1

a part of a rotor of a gas turbine according to an embodiment of the present invention in a perspective view; and

Fig. 2

a cross section perpendicular to a radial longitudinal axis of in Fig. 1 shown blade.

Fig. 1 shows a part of a rotor of a gas turbine according to an embodiment of the present invention in perspective view, Fig. 2 a section perpendicular to a radial longitudinal axis of the blade.

The blade has an airfoil 1, to which a blade root 2 is connected, which is designed as a so-called fir tree root.

Between the airfoil and the blade root, an inner platform 3 is arranged, which has two opposite axial flanges, of which in the Fig. 1, 2 only one flange 3.1 can be seen.

On both circumferentially opposite sides (top, bottom in Fig. 2 ) of the blade, a pocket 4 and 5 is arranged. This is in each case in the axial direction (horizontal in Fig. 2 ) are defined by a first wall 4.1 and 5.1, respectively, and a second wall 4.2 or 5.2 axially spaced therefrom, which faces away from the blade side (at the bottom in FIG Fig. 1 ) of the platform 3 to the blade root 2 and extend radially inward. In the radial direction bounded outside (top in Fig. 1 ) the shovel blade side facing away from the platform 3, the pocket 4 and 5, radially inside when mounted a rotor (not shown) of the gas turbine limit the pocket to which the blade is releasably secured by means of its blade root 2. The pocket 4 or 5 is open on one side in the circumferential direction, wherein a common partition wall 45 delimits the two circumferentially opposite pockets 4, 5 from each other.

The first walls 4.1, 5.1 each have a pocket facing away (right in Fig. 2 ) Outside 4.1A and 5.1A, in particular in the cross section of Fig. 2 is inclined outwards, ie viewed in the circumferential direction on an open end side of the pocket axially diverged away from the pocket. Ie, the in Fig. 2 bottom outside 4.1A diverges in the illustrated cross-section from top to bottom viewed to the right, the in Fig. 2 upper outer side 5.1A diverges from bottom to top, looking to the right. Accordingly, the outside 4.1A converges from the front side (bottom in FIG Fig. 2 ) of the first wall 4.1 viewed in the circumferential direction (upwards in Fig. 2 ) on the airfoil 1 toward the inside or on the pocket 4, the outside 5.1A converges from the end face (top in FIG Fig. 2 ) of the first wall 5.1 viewed in the circumferential direction (down in Fig. 2 ) to the blade 1 to.

Accordingly, the outsides 4.1A, 5.1A of the first walls 4.1, 5.1 are V-like inclined to each other.

The outer sides 4.2A, 5.2A of the second walls 4.2, 5.2 are, however, in the circumferential direction (vertically in Fig. 2 ).

The outer sides 4.1A, 5.1A of the first walls 4.1, 5.1 are parallel to the pocket-facing inner sides 4.1B and 5.1B of the first walls 4.1 and 5.1, respectively. In addition, the outer sides 4.2A, 5.2A of the second walls 4.2, 5.2 parallel to the inner sides 4.2B and 5.2B of the second walls 4.2 and 5.2, so that the first and second walls in the circumferential direction have constant wall thicknesses.

In this way, on the one hand by the outwardly inclined or diverging first walls 4.1, 5.1 provided a Entformungsschräge available, without on the other hand lead to a material accumulation in the middle of the blade, in particular in the region of the intermediate wall 45, as in the case of circumferentially parallel outer sides would result.

The first and second walls 4.1, 5.1 and 4.2, 5.2 of the two opposite pockets 4, 5 are seen in the radial direction (vertically in Fig. 1 ) arched parabolic to the bag.

The pocket-facing outer side 4.1A or 5.1A of the first wall 4.1 or 5.1 of the pocket 4 or 5 is in cross-sections perpendicular to the radial longitudinal axis in a radially outer (top in Fig. 1 ) Half, like Fig. 2 one, and also in cross-sections perpendicular to the radial longitudinal axis in a radially inner (bottom in Fig. 1 ) Half each outwardly inclined. In the transition region of the two halves, the outer sides 4.1A, 5.1A due to the parabolic curvature as well as the parallel thereto inner sides 4.1B and 5.1B are substantially circumferentially parallel.

The pocket-facing outer sides 4.1A, 5.1A, which are inclined away from the pocket, are straight in substantially all cross-sections perpendicular to the radial longitudinal axis of the blade. The outsides 4.1A, 5.1A of the two pockets 4, 5 go in the execution of Fig. 1, 2 in a radius into one another, which is arranged at the height of the intermediate wall 45.

The tangent planes to the outsides 4.1A, 5.1A close in the cross section of the Fig. 2 with the circumferential direction an angle α, which is about 20 °.

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.

LIST OF REFERENCE NUMBERS

1

airfoil

2

blade

3

inner platform

3.1

axial flange

4; 5

bag

4.1; 5.1

first wall

4.1A; 5.1A

outside

4.1B; 5.1B

inside

4.2; 5.2

second wall

4.2A; 5.2A

outside

4.2B; 5.2B

inside

45

partition

Claims (8)

1. Rotor blade for a turbomachine, comprising an airfoil (1) for deflecting flow, a blade root (2) for fastening to a rotor of the turbomachine, an interior platform (3) between the airfoil and the blade root, and a first and a second pocket (4, 5) which are arranged on circumferentially opposite sides of the rotor blade, a first of said pockets (4, 5) being defined by two walls (4.1, 4.2; 5.1, 5.2), which extend from the side of the platform that faces away from the airfoil toward the blade root and are axially spaced apart, a first (4.1, 5.1) of said walls having an outer face (4.1A, 5.1A) which faces away from the pockets and is outwardly inclined in at least one cross section perpendicular to a radial longitudinal axis of the rotor blade such that, as it proceeds away from the rotor blade in the circumferential direction, the outer face (4.1A, 5.1A) of the first wall (4.1, 5.1) diverges in the axial direction (α), characterized in that said outer face (4.1A, 5.1A) which faces away from the pockets is at least substantially parallel to an inner face (4.1B, 4.2B, 5.1B, 5.2B) of the first (4.1, 5.1) of said walls which faces the pockets.
2. Rotor blade according to claim 1, characterized in that a second (4.2, 5.2) of said walls comprises an outer face (4.2A, 5.2A) which faces away from the pockets and is oriented at least substantially in the circumferential direction.
3. Rotor blade according to claim 1, characterized in that a second of said walls comprises an outer face (4.2A, 5.2A) which faces away from the pockets and is outwardly inclined in at least one cross section perpendicular to the radial longitudinal axis of the rotor blade.
4. Rotor blade according to any of the preceding claims, characterized in that at least one outwardly inclined outer face (4.1A, 5.1A, 4.2A, 5.2A) which faces away from the pockets is curved or at least substantially straight in at least one cross section perpendicular to the radial longitudinal axis of the rotor blade.
5. Rotor blade according to any of the preceding claims, characterized in that the first and/or second wall (4.1, 4.2, 5.1, 5.2) is arched axially toward the first pocket when viewed in the radial direction.
6. Rotor blade according to any of the preceding claims, characterized in that the first pocket is made by primary shaping, in particular by casting, and/or by forming, in particular by forging.
7. Rotor blade according to any of the preceding claims, characterized in that the additional, circumferentially opposite second pocket (5) is defined by two additional axially spaced walls (5.1, 5.2), which extend from the side of the platform that faces away from the airfoil toward the blade root, at least a first (5.1) of said additional walls having an additional outer face (5.1A) which faces away from the pockets and is outwardly inclined in at least one cross section perpendicular to a radial longitudinal axis of the rotor blade.
8. Turbomachine, in particular a gas turbine, comprising a rotor and at least one rotor blade according to any of the preceding claims, which is fastened to the rotor, in particular in a form-fitting and/or detachable manner.

Images