TURBINE ROTOR BLADE

Abstract

A turbine rotor blade for a thermal continuous flow machine, wherein a transition region and an aerodynamically shaped turbine blade connected to same, follows a blade foot for securing the turbine rotor blade to a rotor along a notional blade longitudinal axis of the turbine rotor blade from bottom to top. The blade foot has two flat end surfaces facing one another, two contoured side surfaces facing one another and joining the two end surfaces to one another, in which side surface at least one respective carrying edge is formed by creating dovetail- or fir tree-like end surface contour. The carrying edges become free edges or extend into the transition region via concave rounded portions. A channel bordering one of the two end sides is arranged in at least one concave rounded portion, the extension of which channel along the side surface is less than that of the carrying edge.

Claims

1. A turbine rotor blade for a thermal continuous flow machine, comprising: a transition region, as well as an aerodynamically curved airfoil adjoining same, which follows a blade root for securing the turbine rotor blade to a rotor of the turbine from bottom to top along a notional blade longitudinal axis of the turbine rotor blade, wherein the blade root has two mutually opposite flat end surfaces and two mutually opposite contoured side surfaces connecting the two end surfaces to one another, in each of which side surfaces at least one supporting flank is formed, and in which the supporting flanks merge into the transition region or become free flanks via concave rounded portions, a flute adjoining one of the two end sides arranged in at least one concave rounded portion, the extension of which flute along the side surface is less than that of the supporting flank.

2. The turbine rotor blade as claimed in claim 1, wherein the flute has an edge contour with a sharp tapering end, which end points toward the opposite side wall.

3. The turbine rotor blade as claimed in claim 1, wherein each side surface has at least two supporting flanks and the flute is arranged above the supporting flank arranged at the lowest level.

4. The turbine rotor blade as claimed in claim 1, wherein at least one flute is arranged above each supporting flank.

5. The turbine rotor blade as claimed in claim 1, wherein the airfoil comprises a pressure side wall and a suction side wall, which extend from a leading edge to a trailing edge for a working medium, and in which at least two flutes are provided, of which one of the two flutes adjoins the end surface on the leading-edge side and is provided on the side surface on the pressure side, and the other of the two flutes is arranged at the end surface on the trailing-edge side and on the side surface on the suction side.

6. The turbine rotor blade as claimed in claim 1, wherein the two end sides lie opposite one another at a 100%-standardized distance, and the axial length of the extent of the recess is not more than 10%, of said distance.

7. The turbine rotor blade as claimed in claim 5, wherein the axial lengths of the flutes situated diagonally opposite one another are different.

8. A turbine rotor blade arrangement comprising: a turbine rotor blade carrier, which is rotatable in use as intended and on the outer circumference of which a multiplicity of retention grooves is provided in a manner distributed uniformly along the circumference, in which grooves turbine rotor blades as claimed in claim 1 are arranged.

9. The turbine rotor blade as claimed in 6, wherein the axial length of the extent of the recess is not more than 5%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention is explained in greater detail in the following description of the figures by means of a number of illustrative embodiments, which do not restrict the invention further. Here, further features and further advantages are indicated. Of the figures:

[0022] FIG. 1 shows a perspective illustration of a turbine rotor blade,

[0023] FIG. 2 shows the side view of the detail of a blade carrier having a retention groove and a turbine rotor blade seated therein, and

[0024] FIG. 3 shows the side view of the side surfaces of the blade root of the turbine rotor blade from FIG. 2.

DETAILED DESCRIPTION OF INVENTION

[0025] In all the figures, identical features are provided with the same reference signs.

[0026] FIG. 1 shows a turbine rotor blade 10 in a perspective illustration. The turbine rotor blade 10 comprises, from bottom to top along a notional longitudinal axis 12, a blade root 14, adjoining which there is a transition region and, adjoining the latter, an aerodynamically curved airfoil 18. The airfoil 18 is aerodynamically curved in a known manner and comprises a leading edge 20 and a trailing edge 22, which are connected to one another by a pressure side wall 21 and a suction side wall 24.

[0027] In the illustrative embodiment shown, the blade root 14 is of dovetail design and thus comprises two flat end surfaces 26, 28, which lie opposite one another, of which one end surface 26 is arranged on the leading-edge side and the other end surface 28 is arranged on the trailing-edge side. The two end surfaces 26, 28 are connected to one another by means of two opposite side surfaces 30, 32, wherein, in each of said side surfaces 30, 32, a supporting flank 34 and a free flank 35 is formed, with the result that the contours of the end surfaces 26, 28 give a dovetail shape. The supporting flanks 34 merge via a concave rounded portion 36 into the transition region 16, which can comprise, on the one hand, a blade neck and, on the other hand, a platform, which can delimit the flow path of the thermal continuous flow machine on the rotor side.

[0028] The supporting flank 34 and the free flank 35 of the blade root 14, which are radially directly adjacent to one another, are connected to one another by a convex rounded portion and thus form a bead, which is arranged in the relevant side surface 30, 32 and which extends from the end surface 26 on the leading-edge side to the end surface 28 on the trailing-edge side.

[0029] Arranged in at least one concave rounded portion is a flute 38, which adjoins the end side 26 and the extent of which along the side surfaces 30 is less than that of the supporting flank 34 and which reduces the supporting area (see FIG. 2) of the supporting flank 34 (in comparison with the relevant supporting flank 34 without the flute adjoining it). By virtue of the flute 38, lower mechanical loads occur in a turbine rotor blade arrangement 40—comprising a turbine rotor blade carrier 42 which can be rotated during use as intended and on the outer circumference of which a multiplicity of retention grooves 48 are provided in a manner uniformly distributed along the circumference, and in which grooves the turbine rotor blade 10 is arranged, extending the life of the turbine rotor blade carrier 42.

[0030] FIG. 2 shows a detail of the turbine rotor blade arrangement 40, in which a turbine rotor blade carrier 42 is designed as a rotor disk, which can be rotated about a machine axis 44. Just one of the turbine rotor blade retention grooves 48 uniformly distributed along the circumference U, in which a turbine rotor blade 10 is inserted, is shown on the outer circumference 46 of the rotor disk 42. The supporting flanks 34 and free flanks 35 arranged in both side surfaces 30, 32 of the blade root 14 result in a contour in the form of a firtree for the end surface 26 of the blade root 14.

[0031] The supporting flanks 34 are configured symmetrically with respect to the notional longitudinal axis 12 of the turbine rotor blade 10. The flute 38 is arranged in such a way that the distance F between the opposite concave rounded portions 36 and the flute 38 is reduced in comparison with the distance without a flute. At the same time, the flute 38 is embodied in such a way that the contact area of the supporting flank 34 of the blade root 40 and of the supporting flank, opposite thereto, of the retention groove 48 is reduced in the region of the flute 38 in comparison with the contact region in which no flute is provided.

[0032] FIG. 3 shows a plan view of the side surface 30 of the blade root 14 of the turbine rotor blade 10. The two flat end sides 26, 28 lie opposite one another at a 100%-standardized distance A, wherein the longitudinal extent of the flute 38 does not exceed a length L, measured from the end side 26 adjoined by the flute 38, amounting to 10%, advantageously not more than 5%, of the distance A. In this case, it amounts to 3%.