Turbine rotor blade and gas turbine

Patent metadata

Field	Value
Publication number	US-11118461-B2
Application number	US-201916978998-A
Country	US
Kind code	B2
Filing date	Mar 27, 2019
Priority date	Mar 29, 2018
Publication date	Sep 14, 2021
Grant date	Sep 14, 2021

Abstract

A second outer surface ( 49 ab ) of a top plate ( 49 ) is recessed from a first outer surface ( 49 aa ) of the top plate ( 49 ) in the direction away from the inner peripheral surface ( 34 a ) of a turbine casing ( 34 ) so that a step ( 50 ) is formed between the second outer surface ( 49 ab ) and the first outer surface ( 49 aa ). At least part of the discharge opening ( 53 B) of a cooling hole ( 53 ) is disposed in the second outer surface ( 49 ab ). The cooling hole ( 53 ) extends so as to be tilted relative to the second outer surface ( 49 ab ) so that the cooling hole ( 53 ) discharges a cooling medium to the upstream side of a combustion gas flowing between the second outer surface ( 49 ab ) and the inner peripheral surface ( 34 a ) of the turbine casing ( 34 ).

First claim

The invention claimed is:

1. A turbine rotor blade comprising:
a blade body that includes a pressure surface side blade wall and a suction surface side blade wall that extend in a radial direction of a turbine rotor and are connected to each other at a leading edge and a trailing edge and a top plate that is provided at a tip end portion out of end portions of the pressure surface side blade wall and the suction surface side blade wall and includes an outer surface facing an inner peripheral surface of a casing, the tip end portion being disposed on an outer side in the radial direction of the turbine rotor; and
a cooling hole that penetrates the top plate and includes a discharge port through which a cooling medium is discharged to an outside of the top plate,
wherein the outer surface of the top plate includes a first outer surface that is provided at a suction surface side region and a central region and a second outer surface that is provided at a pressure surface side region and constitutes the rest of the outer surface excluding the first outer surface, the suction surface side region being disposed on the suction surface side blade wall side and extending from the leading edge to the trailing edge, the central region being disposed between the pressure surface side region disposed on the pressure surface side blade wall side and extending from the leading edge to the trailing edge and the suction surface side region and extending from the leading edge to the trailing edge, and the pressure surface side region being disposed on the pressure surface side blade wall side and extending from the leading edge to the trailing edge,
wherein the second outer surface is more distant from the inner peripheral surface of the casing than the first outer surface such that a step is formed between the second outer surface and the first outer surface,
wherein a portion where the step is formed is provided with a side surface that connects the first outer surface and the second outer surface to each other and extends along a pressure surface of the pressure surface side blade wall,
wherein the cooling hole extends while being inclined with respect to the second outer surface such that the cooling medium is discharged to an upstream side of combustion gas flowing between the second outer surface and the inner peripheral surface of the casing, and
wherein at least a portion of the discharge port is disposed in the second outer surface.

2. The turbine rotor blade according to claim 1 ,
wherein the cooling hole includes a portion of which a section obtained when the portion is cut in a plane orthogonal to an axial direction of the cooling hole is circular, and
wherein a height of the step in the radial direction of the turbine rotor falls into a range of 0.25D to 2.00D, where D is a diameter of the cooling hole at the section.

3. The turbine rotor blade according to claim 1 ,
wherein the cooling hole includes a portion of which a section obtained when the portion is cut in a plane orthogonal to an axial direction of the cooling hole is circular, and
wherein a distance from a connection position between the side surface and the second outer surface to an axis of the cooling hole in a direction orthogonal to the side surface is equal to or greater than 0 and equal to or smaller than D, where D is a diameter of the cooling hole at the section.

4. The turbine rotor blade according to claim 1 ,
wherein an angle formed by an axis of the cooling hole and the second outer surface is equal to or greater than 30° and equal to or smaller than 45°.

5. The turbine rotor blade according to claim 1 , further comprising:
a first inclined surface that is provided between the second outer surface and the pressure surface of the pressure surface side blade wall, connects the second outer surface and the pressure surface to each other, and is inclined with respect to the second outer surface and the pressure surface; and
a second inclined surface that is provided between the first outer surface and a suction surface of the suction surface side blade wall, connects the first outer surface and the suction surface to each other, and is inclined with respect to the first outer surface and the suction surface.

6. The turbine rotor blade according to claim 3 ,
wherein the blade body includes a metal substrate that corresponds to a shape of the blade body and a thermal insulation coating layer that covers an outer surface of the metal substrate, and
wherein the first outer surface, the second outer surface, and the side surface are formed by an outer surface of the thermal insulation coating layer.

7. The turbine rotor blade according to claim 3 ,
wherein the blade body includes a metal substrate that corresponds to a shape of the blade body and a thermal insulation coating layer that covers an outer surface of the metal substrate except for the second outer surface, and
wherein the first outer surface and the side surface are formed by an outer surface of the thermal insulation coating layer, and
wherein the second outer surface is formed by the outer surface of the metal substrate.

8. The turbine rotor blade according to claim 1 ,
wherein a plurality of the cooling holes are formed at intervals from the leading edge to the trailing edge along the pressure surface of the pressure surface side blade wall.

9. The turbine rotor blade according to claim 8 ,
wherein a cooling channel through which the cooling medium flows is formed inside the blade body,
wherein the plurality of cooling holes include a plurality of first cooling holes that are formed in a leading edge side region positioned on the leading edge side and a trailing edge side region positioned on the trailing edge side and a plurality of second cooling holes that are formed in an intermediate region disposed between the leading edge side region and the trailing edge side region,
wherein a section of the first cooling hole which is cut in a plane orthogonal to an axial direction of the first cooling hole is circular,
wherein the second cooling hole includes a first portion that is formed on the cooling channel side and a second portion that is formed outside the first portion in a state of being connected to the first portion and includes the discharge port,
wherein a section of the first portion which is cut in a plane orthogonal to an axial direction of the second cooling hole is circular and a diameter of the first portion in the axial direction of the second cooling hole is constant, and
wherein a width of the second portion in a direction along the pressure surface of the pressure surface side blade wall increases toward the discharge port from the first portion.

10. A gas turbine comprising:
a turbine that includes a turbine rotor in which a plurality of the turbine rotor blades according to claim 1 are disposed in a circumferential direction and an axial direction and the plurality of turbine rotor blades;
a compressor that generates compressed air by sucking in air for combustion;
a combustor that injects fuel into the compressed air to cause combustion and to generate combustion gas with which the turbine is driven; and
a casing that includes a ring segment and accommodates the turbine rotor and the plurality of turbine rotor blades, the ring segment facing the first and second outer surfaces of the top plate in a state where a gap is interposed therebetween.

Assignees

• Mitsubishi Heavy Ind Ltd
• Mitsubishi Power Ltd

Inventors

• Ito Ryuta
• Iida Koichiro

Classifications

• F05D2260/202

  by film cooling · CPC title

• F01D5/20

  Specially-shaped blade tips to seal space between tips and stator {(F01D5/225 takes precedence)} · CPC title

• F02C7/28

  Arrangement of seals · CPC title

• F01D5/18 Primary

  Hollow blades, {i.e. blades with cooling or heating channels or cavities (structure of hollow blades in general F01D5/147)}; Heating, heat-insulating or cooling means on blades · CPC title

• F05D2240/307

  related to the tip of a rotor blade · CPC title