Axial rotor portion and turbine rotor blade for a gas turbine

Abstract

A turbine rotor blade is provided with a blade root, platform adjoining it, and turbine blade on that side of the platform which faces away from the blade root, with at least one opening for feeding coolant into the turbine rotor blade interior on an underside of the blade root, which opening merges into a coolant duct. An axial rotor section for a rotor is provided, having an outer circumferential surface adjoining two end-side first side surfaces with rotor blade holding grooves distributed over the circumference and extending along an axial direction, wherein a turbine rotor blade is arranged in every holding groove, wherein a multiplicity of sealing elements are at the side of a side surface of the rotor section, and lie opposite the end sides of blade roots to form a gap. Multiple outlet holes for impingement cooling of the sealing elements are provided in the end surface.

Claims

1. A turbine rotor blade comprising: a blade root, an adjoining platform and a main blade part located on that side of the platform which is remote from the blade root, wherein at least one opening for feeding a coolant into the interior of the turbine rotor blade is provided on an underside of the blade root and which merges into a coolant duct, and wherein a number of outlet holes for impact cooling of adjacent components are provided in at least one of two end faces of the blade root and open into the coolant duct.

2. The turbine rotor blade as claimed in claim 1, in which the coolant duct is directly adjacent to a respective end face of the blade root.

3. The turbine rotor blade as claimed in claim 1, in which at least one spacer for an abutment of a sealing element is provided on a respective end face.

4. The turbine rotor blade as claimed in claim 1, in which an element which generates a pressure loss for the coolant is arranged on the underside between the at least one opening and a corresponding end face of the two end faces.

5. An axial rotor portion for a rotor of a turbine, comprising: an outer circumferential surface which adjoins two first side surfaces of the axial rotor portion and in which rotor blade retainer grooves distributed over the outer circumferential surface and extending along an axial direction are provided for rotor blades of the turbine, a turbine rotor blade comprising a blade root arranged in each retainer groove, and a multiplicity of sealing elements provided adjacent a side surface of the axial rotor portion and opposite end faces of blade roots to form a gap between the multiplicity of sealing elements and the end faces, wherein each turbine rotor blade further comprises an adjoining platform and a main blade part located on that side of the platform which is remote from the blade root, wherein at least one opening for feeding a coolant into an interior of a respective turbine rotor blade is provided on an underside of the respective blade root and merges into a respective coolant duct in the respective turbine rotor blade, and wherein a number of outlet holes for impact cooling of adjacent components are provided in at least one of the two end faces of each blade root and open into a respective coolant duct.

6. A method for cooling a sealing element of an axial rotor portion as claimed in claim 5, comprising: flowing cooling air for impact cooling of the multiplicity of sealing elements out through the number of outlet holes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and features of the invention will be explained in more detail on the basis of an exemplary embodiment. In the drawing:

(2) FIG. 1 shows an axial rotor portion with turbine rotor blades arranged on the external circumference,

(3) FIG. 2 shows the cross-sectional view as shown in FIG. 1 along the sectional line II-II,

(4) FIG. 3 shows a longitudinal section through the root region of a turbine rotor blade according to the invention, and

(5) FIG. 4 shows a perspective illustration of the blade root of the turbine rotor blade according to the invention.

DETAILED DESCRIPTION OF INVENTION

(6) In all of the figures, identical features are provided with the same reference signs.

(7) FIG. 1 shows an axial rotor portion 10 in a lateral view and FIG. 2 shows an axial rotor portion 10 in a cross section as per the sectional line II-II shown in FIG. 1. For each turbine rotor blade 14, referred to hereinbelow as rotor blade for short, to be secured against axial displacement within the rotor blade retainer groove 12 thereof, provision is made of two adjacent sealing elements 16, which in each case equally cover the opening on the end face of the respective rotor blade retainer groove 12. Each sealing element 16 sits with its radially inner end 18 in a groove 20 provided on the end face on a rotor disk 19 and with its radially outer end 22 in a securing groove 24, which is provided on the underside 26 of a platform 28 of the rotor blade 14. In order to secure each sealing element 16 against displacement in the circumferential direction U, a radially rectilinear sheet metal strip 30 is fastened to each of them. Each sheet metal strip 30 ends at its radially outer end 32 in a uniformly converging tip 34. Beveled edges 36 are present on the platforms 28 of the rotor blades 14, with in each case two opposing edges 36 of directly adjacent rotor blades 14 forming a pointed recess 38, into which the tip 34 of the sheet metal strip 30 can protrude and bear to secure the sealing element 16 against displacement in the circumferential direction U.

(8) The sealing elements 16 moreover ensure the separation of two spaces 37, 39, in which firstly coolant and secondly a mixture of coolant and a hot-gas stream can arise.

(9) To fasten the sheet metal strips 30 to the sealing element 16, the latter is provided with two parallel slots 40, through which the sheet metal strip 30 which has already been pre-bent in a U shape is inserted. That end 41 of the sheet metal strip 30 which lies opposite the tip 34 is already bent into the position shown in FIG. 2 for fastening the sheet metal strip 30 before the sealing element 16 is mounted on the rotor disk 19.

(10) After the rotor blades 14 have been mounted in the rotor disks 19, the sealing elements 16 together with the pre-assembled sheet metal strips 30 are threaded in succession into the endlessly encompassing groove 20 arranged on the rotor disk 19 and into the securing groove 24 arranged on the underside 26 of the platform 28. The sealing elements 16 are positioned along the circumference of the groove 20 in such a way that each sheet metal strip 30 lies opposite a recess 38. Then, the tips 34 of the sheet metal strips 30 are bent into the recesses 38, in order to rule out displacement of the sealing elements 16 in the circumferential direction U.

(11) Outlet holes 58 are provided in an end face 52 of the blade root 54 and in the side surfaces 53 of what are termed claws 56, which form the outer rim of the rotor disk 19 between two directly adjacent retainer grooves 12. As can be seen from FIG. 2, the outlet holes 58 arranged in the blade root 54 are connected to a coolant duct 60, the inflow-side opening 62 of which for feeding a coolant is arranged in the underside 64 of the blade root 54.

(12) During the operation of a gas turbine equipped with such a rotor portion 10, coolant 66 flows through a cooling duct 65 arranged in the rotor disk 19 into the clearance 67 between the blade root underside 64 and the groove base of the retainer groove 12. From there, some of the coolant 66 passes to the opening 62, after which it then enters into the coolant duct 60. On account of the pressure gradient which is present, the coolant 66 then flows out through the outlet holes 58 in the form of impact cooling jets and strikes the sealing element 16 with an impact cooling action.

(13) In order to set the desired pressure gradient, it may be expedient to arrange an element 68 which generates a pressure loss on the underside 64 of the blade root 54 between the opening 62 and the end face 52. Said element can also be in the form of a sealing element.

(14) A spacer element 70 can also be provided on the end face 52 to achieve a defined distance between the end face 52 of the blade root 54 and the sealing element 16.

(15) The supply of cooling air to the outlet holes 58 arranged in the claws 56 can be achieved with the aid of suitable bores (not shown) in the rotor disk 19.

(16) FIGS. 3 and 4 show the turbine rotor blade 14 according to the invention comprising the blade root 54, a platform 28 and the main blade part 15 arranged thereon, with the latter only being shown in part, however. The feed opening 62 and the outlet holes 58 are also shown. The distance between the end face 52 of the blade root 54 and the opening 62 is comparatively small, and therefore the coolant duct 60 shown in cross section in FIG. 3 is arranged comparatively close to the end face 52 assigned thereto. The coolant duct 60 extends parallel to the substantially planar end face 52 of the blade root 54.

(17) Overall, the invention therefore relates to a turbine rotor blade 14 having a blade root 54, an adjoining platform 28 and a main blade part 15 located on that side of the platform 28 which is remote from the blade root 54, wherein at least one opening 62 for feeding a coolant 66 into the interior of the turbine rotor blade is provided on an underside 64 of the blade root 54 and merges into a coolant duct 60. The invention also relates to an axial rotor portion 10 for a rotor 23 of a turbine, having an outer circumferential surface which adjoins two first side surfaces 53 at the end and in which rotor blade retainer grooves 12 distributed over the circumference and extending along an axial direction are provided for rotor blades 14 of the turbine, a turbine rotor blade 14 being arranged in each retainer groove 12, wherein a multiplicity of sealing elements 16 are provided to the side of a side surface 53 of the rotor portion 10 and lie opposite the end faces 52 of the blade roots 54 to form a gap. In order to achieve improved cooling of the sealing element 16, which increases the service life thereof or makes the latter suitable for higher ambient temperatures, it is proposed that a multiplicity of outlet holes 58 for the impact cooling of the sealing elements 16 are provided in the side surface 53 and/or in the end face 52.