EP2787178B1 - Guide vane assembly - Google Patents

Description

The present invention relates to a vane arrangement for a turbomachine, in particular a gas turbine, and a gas turbine, in particular an aircraft engine gas turbine, with one or more such vane arrangements. A generic vane arrangement is for example from the EP 2 397 653 A1 and the US 2012/128472 A1 known. In addition, it was also on the US 5,248,240 pointed.

In particular, vane arrangements in aircraft engine gas turbines are subject to high thermal loads. Therefore, it is known from the field of internal practice, for example, to provide cooling slots in rear radial flanges of outer shrouds of such vane assemblies through which cooling air flows during operation to cool the vane assemblies and / or a housing in which it is disposed.

Such cooling slots represent a possible root of component cracks.

An object of an embodiment of the present invention is to provide an improved turbomachine, in particular an improved gas turbine.

This object is achieved by a vane arrangement with the features of claim 1. Claim 7 provides a corresponding gas turbine 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 compressor and / or turbine stages, in particular low-pressure compressor and / or turbine stages, each having a vane arrangement.

A vane assembly according to one aspect of the present invention comprises a single or multiple outer shroud from which two or more vanes project radially inward. The vanes can be detachable or permanent with connected to the outer shroud, in particular integrally made with this or materially connected thereto, in particular welded, be.

In one embodiment, the outer shroud has a, in particular at least substantially conical, circumferential surface and at least one radial flange, in particular a rear radial flange in the throughflow direction and / or a front radial flange in the flow direction. In one embodiment, the guide vane assembly by means of at least one radial flange, in particular by a rear radial flange and / or a front radial flange with a housing, in particular releasably and / or positively connected, preferably suspended in this.

In one embodiment, seen in the circumferential direction, between a pair of adjacent vanes, in a development between all vanes of the vane assembly, each arranged a pair of axial ribs which are spaced apart in the circumferential direction and from the outer surface of the outer shroud radially outward or on the protrude away from the guide vane. Additionally or alternatively, the axial ribs of at least one, in particular rear and / or front, radial flange of the outer cover strip can project axially toward the lateral surface. In one embodiment, the axial ribs with the lateral surface and / or at least one, in particular a rear and / or a front, radial flange, materially connected.

Due to the axial ribs, a possible crack propagation in one embodiment can advantageously be guided between the axial ribs and thus limited to a specific region of the outer platform. In particular, in a development, crack propagation into an area in which a guide blade is arranged is made more difficult, preferably blocked, and thus directed into areas which are more favorable for this purpose.

In one embodiment, a, in particular rear, radial flange has one or more recesses. In particular, these can be designed like slits and / or produced by electrical discharge machining (EDM) and / or extend, at least substantially, in the radial direction, in particular from a radially outer edge of the radial flange. They are provided or arranged in an embodiment for the flow through a cooling fluid, in particular cooling air.

As explained in the introduction, form such recesses, in particular radially inner ends of slot-like recesses, due to the notch effect preferred Anrißstellen.

Therefore, according to the invention, the axial ribs of an axial rib pair of adjacent axial ribs extend radially outward at least as far as a radially inner end from a recess, in particular a cooling slot, in a, in particular rear, radial flange. They are in one embodiment, seen in the circumferential direction, arranged on either side of the recess or the recess is arranged in the Umtangsrichtung between the two adjacent axial ribs of a Axialrippenpaares. In this way, in one embodiment, a possible crack propagation is already limited at its root between the axial ribs and guided by them at the radial flange and further in the lateral surface.

The axial ribs are in one embodiment, at least substantially, L-shaped, wherein one leg is integrally connected to the radial flange and the other leg is materially connected to the lateral surface. In this way, a possible crack propagation in both the radial flange and in the manhole can be performed, in particular limited in one embodiment with the lowest possible cost of materials. The leg connected to the radial flange may, as stated above, in particular extend radially outward at least up to a radially inner end of a recess. Such an axial rib thus extends radially outward at least as far as the radially inner end only in the area of the radial flange. Similarly, viewed in the circumferential direction, an axial rib can also be triangular, rectangular, Ü-shaped or the like, for example.

The axial ribs extend or run in an embodiment, at least substantially, in the axial direction. Likewise, they may also include an angle with the axial direction or axis of rotation of the turbomachine in one embodiment corresponds to a stagger angle of the vanes. For a more compact representation such oblique ribs are referred to as axial ribs in the context of the present invention. Axial ridges can be rectilinear or curved or extend axially. Generally, in one embodiment, the axial ribs may be equidistant from the adjacent vanes in the circumferential direction, at least substantially. In particular, a minimum circumferential clearance between an axial rib of an axial rib pair and its adjacent vane may be, at least substantially, equal to the minimum circumferential clearance between the other axial rib of that axial rib pair and the adjacent vane.

The axial ribs may extend in one embodiment from a rear to a front radial flange. In another embodiment, the axial ribs, in particular starting from a rear radial flange, end axially in front of a further, in particular front, radial flange. It has been found that this customary crack sufficient and yet the material cost of the axial ribs can be minimized.

In one embodiment, the axial ribs are connected to the lateral surface and / or the radial flange in a rounding, in particular a so-called fillet. This can make it difficult to climb over the ribs by a crack.

In one embodiment, the lateral surface is lowered in the circumferential direction between the axial ribs radially inward. In this way, a possible crack additionally be directed between the pair of axial ribs. Similarly, in one embodiment, the lateral surface increases in the circumferential direction between the axial ribs radially outward, in particular thickened between the axial ribs, be to complicate the progression of a crack. In particular, outside the Axialrippenpaare, in a development between the Axialrippenpaaren, the lateral surface, at least substantially, the same wall thickness as the radial flange.

The axial ribs can be made separately in one embodiment and then materially connected to the lateral surface and / or the radial flange, in particular be welded. Likewise, they can be produced by build-up welding or be urformed with the lateral surface and / or the radial flange.

• Fig. 1 einen Teil einer Leitschaufelanordnung einer Gasturbine nach einer Ausführung der vorliegenden Erfindung mit einem Axialrippenpaar in perspektivischer Ansicht; und
• Fig. 2 einen Axialschnitt zwischen dem Axialrippenpaar der Fig. 1.

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 portion of a guide vane assembly of a gas turbine according to an embodiment of the present invention with an axial rib pair in perspective view; and
• Fig. 2 an axial section between the Axialrippenpaar the Fig. 1 ,

Fig. 1, 2 show a portion of a vane assembly of a low pressure compressor stage of an aircraft engine gas turbine according to an embodiment of the present invention in perspective view and an axial section, respectively.

The vane assembly has an outer shroud from which a plurality of vanes 1 radially inward (vertically downward in Fig. 1, 2 ) stand out. The foot contours of the guide vanes 1 are in Fig. 1 indicated by dashed lines.

The outer shroud has a substantially conical surface 2, one in the flow direction (from left to right in Fig. 1, 2 ) rear radial flange 3 and a front in the flow direction radial flange 4, in Fig. 1 is omitted. Through the front and rear radial flange, the outer shroud is mounted in a housing (not shown), as for example in the EP 1 462 616 A2 is disclosed, to which reference is made.

Seen in the circumferential direction (perpendicular to the plane of the Fig. 2 ) is arranged between the two adjacent vanes 1, a pair of axial ribs 5, which are spaced apart in the circumferential direction and from the outer surface 2 of the outer shroud radially outward (vertically upwards in FIG Fig. 1, 2 ) and from the rear Radial flange 3 axially towards the lateral surface 2 out (from right to left in Fig. 2 ) protrude and are welded to each.

In the rear radial flange 3, a slot-like recess 6 is formed by spark erosion, which extends substantially in the radial direction from a radially outer edge of the rear radial flange 3 (top in FIG Fig. 1 ) and for the flow through a cooling fluid, in particular cooling air, is provided.

The radially inner end (bottom in Fig. 1 ) of this cooling slot 6 forms a preferred Anrißstelle for a crack 7 due to the notch effect.

The axial ribs 5 are viewed in the circumferential direction (in the plan view of Fig. 2 ) L-shaped, with a leg (right in Fig. 2 ) is materially connected to the rear radial flange 3 and the other leg (bottom in Fig. 2 ) is materially connected to the lateral surface 2. The leg connected to the rear radial flange 3 extends radially outward to the radially inner end of the recess 6, which is arranged in the circumferential direction between the two adjacent axial ribs 5. In this way, a propagation of the crack 7 can already be limited at its root between the axial ribs 5 and guided by these at the radial flange 3 and in the lateral surface 2.

The axial ribs 5 extend substantially in the axial direction or parallel to a stagger angle of the guide vanes 1 and are equidistant from the adjacent stator vanes 1 in the circumferential direction.

The axial ribs 5 end, starting from the rear radial flange 3, axially in front of the front radial flange 4 (see. Fig. 2 ). It has been found that this customary crack sufficient and yet the material cost of the axial ribs can be minimized.

The axial ribs are connected to the lateral surface 2 and the rear radial flange 3 in a fillet 8. As a result, an over-climbing of the ribs 5 are made difficult by the crack 7.

The lateral surface 2 is slightly lowered in the circumferential direction between the axial ribs 5 radially inward.

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 the claims.

LIST OF REFERENCE NUMBERS

1

vane

2

lateral surface

3

rear radial flange

4

front radial flange

5

axial rib

6

cooling slot

7

Crack

8th

fillet

Claims (7)

1. Vane assembly for a turbomachine, in particular a gas turbine, comprising an outer shroud from which at least two vanes (1) protrude radially towards the inside, comprising a pair of axial ribs (5) which are spaced apart from each other in the peripheral direction and protrude radially towards the outside from a lateral surface (2) of the outer shroud and/or axially to the lateral surface from a radial flange (3) of the outer shroud in the peripheral direction between two adjacent vanes (1), characterized in that the axial ribs extend, at least in the region of the radial flange, radially towards the outside, at least as far as a radially inner end of a recess (6), in particular a slot-like recess, in the radial flange.
2. Vane assembly according to the preceding claim, characterized in that the axial ribs are at least substantially L-shaped and each comprise one leg which is integrally connected to the radial flange and one leg which is integrally connected to the lateral surface.
3. Vane assembly according to either of the preceding claims, characterized in that the axial ribs end before a further radial flange (4) of the outer shroud.
4. Vane assembly according to any of the preceding claims, characterized in that the axial ribs are connected to the lateral surface and/or the radial flange in a fillet (8).
5. Vane assembly according to any of the preceding claims, characterized in that, in the peripheral direction, the lateral surface is sunk radially towards the inside between the axial ribs.
6. Vane assembly according to any or the preceding claims, characterized in that the axial ribs are welded to the lateral surface and/or the radial flange, in particular in a fillet (8), or are produced by means of deposition welding.
7. Gas turbine, in particular a gas turbine in an aircraft engine, comprising at least one compressor stage and/or turbine stage comprising a vane assembly according to any of the preceding claims, characterized in that the vane assembly is connected, in particular releasably connected, to a housing of the gas turbine by means of the radial flange (3).

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