Rotor, axial compressor, installation method

Abstract

A rotor of a multi-staged axial compressor which extends along an axis of rotation. The rotor has a shaft which has rotor blade slots. Rotor blades of the rotor are arranged next to one another in the circumferential direction and are each secured to the rotor blade slots by a blade root to form a respective rotor blade stage. At least two rotor blade stages are provided in axial succession and an interspace slot, extending in the circumferential direction, is provided in the shaft axially between the two rotor blade stages. The rotor blade slots open into the interspace slots and blade roots of the rotor blades are insertable radially into the interspace slots and can be pushed into the rotor blade slots. The rotor has an interspace cover which covers the interspace slots, wherein the interspace cover is designed segmented into interspace cover segments in the circumferential direction.

Claims

1. A rotor of a multi-stage axial compressor, which extends along an axis of rotation, with axial, radial and circumferential directions existing relative to the axis of rotation, the rotor comprising: a shaft, wherein the shaft has rotor blade grooves, rotor blades, wherein the rotor blades of the rotor which are arranged next to one another in the circumferential direction and are each fastened to a respective rotor blade groove by means of a blade root defining a respective rotor blade stage, wherein at least two rotor blade stages are provided in axial succession, and an interspace groove, extending in the circumferential direction, is provided in the shaft axially between the two rotor blade stages, wherein the rotor blade grooves open into the interspace groove and are designed such that each respective blade root is are insertable radially into the interspace groove and pushed from there into the respective rotor blade groove, and an interspace cover which covers the interspace groove, wherein the interspace cover is designed segmented into interspace cover segments in the circumferential direction, wherein the interspace cover segments are fastened in a form-fitting manner to the shaft, wherein the shaft is an integral component over at least one axial portion of the two rotor blade stages and the interspace groove, and the interspace groove is formed by a turning process performed on the integral component, wherein the interspace groove at least partially has, extending in the circumferential direction, a first undercut which is formed so as to interact in a form-fitting manner in the radial direction with a second undercut of the interspace cover segments in a manner blocking movement of the interspace cover segments in the radial direction.

2. The rotor as claimed in claim 1, wherein the interspace cover covers the interspace groove such that a substantially continuously radial transition is produced in the axial direction of a radially outer surface between the rotor blade stage positioned upstream and the interspace cover, and between the interspace cover and the rotor blade stage positioned downstream.

3. The rotor as claimed in claim 1, wherein the interspace cover is configured to secure the rotor blades against axial displacement in their respective rotor blade groove in an end position.

4. The rotor as claimed at least in claim 1, wherein at least one interspace lock piece is provided for the interspace groove, which interspace lock piece is arranged at a certain first circumferential position of the interspace groove at which at least one of the interspace groove and the interspace lock piece is designed to avoid interaction of the undercuts for allowing radial insertion of the interspace cover segments.

5. The rotor as claimed in claim 4, wherein the interspace groove does not have the first undercut at the certain first circumferential position.

6. The rotor as claimed in claim 1, wherein the interspace cover segments and/or an interspace lock piece are fastened to the shaft by means of at least one screw.

7. An axial compressor comprising: a rotor as claimed in claim 1.

8. A method for installing a rotor of an axial compressor as claimed in claim 1, the method comprising: a) providing the shaft, b) inserting the blade roots of the rotor blades radially into the interspace groove, c) pushing the blade roots of the rotor blades axially into the rotor blade grooves, d) installing the interspace cover segments on the shaft in a form-fitting manner to secure the axial position of the blade roots of the rotor blades in the rotor blade grooves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is clarified in more detail below on the basis of a specific exemplary embodiment with reference to drawings, in which:

(2) FIG. 1 shows a schematic three-dimensional view of two adjacent rotor blade stages and an interspace groove with an interspace cover,

(3) FIG. 2 shows a schematic three-dimensional view of two adjacent rotor blade stages with an interspace groove arranged therebetween and an interspace cover in a further variant embodiment, and

(4) FIG. 3 shows a schematic sectional view of second adjacent rotor blade stages of an axial compressor with a guide vane stage located therebetween in the region of the interspace with an interspace groove and an interspace cover.

DETAILED DESCRIPTION OF INVENTION

(5) FIGS. 1 and 2 each show different variants of the invention with reference to two adjacent rotor blade stages RBS in a schematic three-dimensional view. FIG. 3 shows a schematic longitudinal section through two adjacent rotor blade stages RBS of an axial compressor ACO which is only illustrated partially here. For simplification of the illustration, the rotor blade stages RBS are each reproduced only as a single rotor blade RB, wherein a plurality of rotor blades arranged next to one another along a circumferential direction CD actually produce a rotor blade stage RBS.

(6) A shaft SH of a rotor R of an axial compressor ACO extends along an axis of rotation X. Shown in the respective illustrations, in each case listed in axial sequence are: a rotor blade stage RBS, an interspace with an interspace groove and an interspace cover IC, and a further rotor blade stage RBS. Between the rotor blade stages radially opposite the interspace groove IG, a guide vane stage GVS consisting of guide vanes GV is also reproduced in FIG. 3. The guide vanes GV are formed without a shroud extending in the circumferential direction and located radially in the inside of the guide vanes and are accordingly self-supporting. The rotor blades RB are each connected to the shaft SH in a form-fitting manner in rotor blade grooves RBG. For this purpose, blade roots RBF are introduced into the rotor blade grooves RBG, said blade roots preventing the rotor blades RB from moving radially out of the shaft SH of the rotor R. As reproduced in FIG. 2, the rotor blade roots RBF are designed in the form of a hammerhead and correspond in shape to the rotor blade groove in the shaft SH, and therefore the undercuts of the hammerhead root together with those of the rotor blade groove form a form-fitting connection against axial movement. Alternatively, the blade root can also be designed as a Christmas tree root, or can have a different shape with undercuts. Between the two rotor blade stages RBS, an interspace groove IG is located in the shaft SH, said interspace groove extending in the circumferential direction CD. The rotor blade grooves, wherein one rotor blade groove RBG is provided for each individual rotor blade RB, all open into said interspace groove IG. In this case, a single interspace groove IG is provided for the installation of the rotor blades RB for two rotor blade stages RBS, on both sides of the interspace groove IG. The rotor blades RB are inserted radially with their rotor blade root RBS into the interspace groove IG and are subsequently pushed substantially axially into the rotor blade groove RBG. After all of the rotor blades RB are positioned in their end position in the rotor R or the shaft SH, the interspace cover IC is attached to the shaft SH or the rotor R for covering the interspace groove IG radially to the outside. Alternatively, individual interspace cover segments of the interspace cover IC can also be mounted in the regions in which the rotor blades RB have already been inserted using the interspace groove IG and are accordingly secured in their end position by means of the interspace cover segments ICS against axial displacement. The interspace cover segments ICS close the interspace groove IG in such a manner that a substantially smooth and continuous transition is produced in the axial direction between the upstream rotor blade stage RBS and the interspace groove IG or the interspace cover IC and the downstream rotor blade stage RBS. The interspace cover segments ICS are attached in a form-fitting manner to the shaft SH. At a certain first circumferential position of the interspace groove IC, the shaft SH or interspace groove IG is designed differently than over the rest of the circumference for the purpose of the radial insertion of the interspace cover segments ICS. This point is reproduced schematically in FIG. 1 where an interspace cover segment ICS has a hammerhead root, and said hammerhead root can be inserted in the circumferential direction with a second undercut L2 into a corresponding formation with a first undercut L1 of the interspace groove IG. The interspace groove does not have any first undercut L1 at the first circumferential position, and therefore a radial insertion of the hammerhead root of the interspace cover segments ICS is possible. An alternative to the hammerhead roots of FIG. 1 shows a variant of the invention which is reproduced in FIG. 2, wherein the interspace cover segments ICS have an omega shape and the second undercut L2 extends beyond the axial region of the interspace groove IG. The corresponding first circumferential position is not illustrated in FIG. 2 and, for the purpose of the radial insertion of the interspace cover segments ICS, has to has recesses which extend axially into the region of the rotor blade stages RBS.

(7) FIG. 3 shows a possibility as to how an interspace cover segment ICS can be designed at the first circumferential position as an interspace lock piece ICL and can be fastened to the shaft SH. By omitting the form fit by means of the first undercut L1 and the second undercut L2, as is advantageously provided at the remaining circumferential positions of the interspace groove IG, the interspace lock piece ICSL is secured radially and against movement in the circumferential direction by means of a screw SR. In this manner, all of the interspace cover segments ISC are also secured in a form-fitting manner in the circumferential position. It is possible in principle that all of the interspace cover segments ICS are fastened to the shaft SH against radial movement, even without a further form fit, in a particular development of the invention, additionally or exclusively by means of a screw SR.