Turbine blade and gas turbine

Patent metadata

Field	Value
Publication number	US-11230932-B2
Application number	US-201916366327-A
Country	US
Kind code	B2
Filing date	Mar 27, 2019
Priority date	Mar 29, 2018
Publication date	Jan 25, 2022
Grant date	Jan 25, 2022

Abstract

A turbine blade includes a blade body including a top plate at a tip portion which is outside of a turbine rotor in a radial direction of the turbine blade and has an outer surface configured to face an inner circumferential surface of a casing, and a tip thinning which protrudes radially outward in the radial direction of the turbine blade from the outer surface of the top plate and extends from a leading edge side of the blade body to a trailing edge side of the blade body. A protrusion amount of the tip thinning based on the outer surface of the top plate is 0.25 times or more and 2.00 times or less a diameter of a discharge port of a cooling hole which passes through the top plate.

First claim

What is claimed is:

1. A turbine blade, comprising:
a blade body including a pressure-surface-side blade wall and a suction-surface-side blade wall extending in a radial direction of the turbine blade and being connected to each other at a leading edge of the blade body and a trailing edge of the blade body, and a top plate having an outer surface configured to face an inner circumferential surface of a casing, the top plate being provided at a tip portion, among end portions of the pressure-surface-side blade wall and the suction-surface-side blade wall; and
a tip-thinning portion protruding outward in the radial direction of the turbine blade from the outer surface of the top plate, the tip-thinning portion extending from a leading edge side of the blade body to a trailing edge side of the blade body, and the tip-thinning portion being closer to a pressure-surface-side blade wall side of the top plate than a suction-surface-side blade wall side of the top plate,
wherein:
the blade body includes: (i) a cooling hole defined to pass through the top plate, (ii) an introduction port defined at a position of an inner surface of the top plate and configured to introduce a cooling medium into the cooling hole, and (iii) a discharge port defined in the outer surface of the top plate closer to the pressure-surface-side blade wall side of the top plate than the tip-thinning portion and configured to discharge the cooling medium via the cooling hole;
a protrusion amount of the tip-thinning portion, based on the outer surface of the top plate, is within a range of at least 0.25 times to at most 2.00 times a diameter of the discharge port of the cooling hole;
the outer surface of the top plate extends in a planar shape from the tip-thinning portion toward the suction-surface-side blade wall side of the top plate, and is configured to direct the cooling medium which has passed through the tip-thinning portion along the outer surface of the top plate toward the suction-surface-side blade wall side of the top plate; and
the tip-thinning portion is the only tip-thinning portion protruding outward in the radial direction of the turbine blade from the top plate.

2. The turbine blade according to claim 1 , wherein the tip-thinning portion is provided only adjacent to the pressure-surface-side blade side of the top plate.

3. The turbine blade according to claim 1 , wherein the cooling hole is one of a plurality cooling holes arranged sequentially in a direction from the leading edge side of the blade body to the trailing edge side of the blade body.

4. The turbine blade according to claim 3 , wherein one of the plurality of cooling holes is inclined with respect to a pressure surface that is an outer surface on the pressure-surface-side blade wall, the one of the plurality of cooling holes facing the leading edge side of the blade body or the trailing edge side of the blade body.

5. The turbine blade according to claim 1 , wherein the top plate has an inclined surface which is disposed on an outside of the outer surface of the top plate to surround the outer surface of the top plate and inclined with respect to the outer surface of the top plate.

6. The turbine blade according to claim 5 , wherein a width of the inclined surface is within a range of at least 0.25 times to at most 3.00 times the diameter of the discharge port of the cooling hole.

7. The turbine blade according to claim 4 , wherein the top plate has an inclined surface which is disposed on an outside of the outer surface of the top plate to surround the outer surface of the top plate and inclined with respect to the outer surface of the top plate.

8. The turbine blade according to claim 1 , wherein an angle between the outer surface of the top plate located closer to the suction-surface-side blade wall side of the top plate than the tip-thinning portion and an axis of the cooling hole is 25° or more and 65° or less.

9. The turbine blade according to claim 4 , wherein an angle between the outer surface of the top plate located closer to the suction-surface-side blade wall side of the top plate than the tip-thinning portion and an axis of the cooling hole is 25° or more and 65° or less.

10. The turbine blade according to claim 1 , wherein a width of the outer surface of the top plate located closer to the pressure-surface-side blade wall side of the top plate than the tip-thinning portion is within a range of at least one times to at most three times the diameter of the discharge port of the cooling hole.

11. The turbine blade according to claim 4 , wherein a width of the outer surface of the top plate located closer to the pressure-surface-side blade wall side of the top plate than the tip-thinning portion is within a range of at least one times to at most three times the diameter of the discharge port of the cooling hole.

12. The turbine blade according to claim 1 , further comprising a flow passage-forming member provided in the blade body and configured to form a flow passage for the cooling medium in the blade body so as to guide the cooling medium to a boundary portion between the top plate and the suction-surface-side blade wall and then guide the cooling medium to the cooling hole.

13. The turbine blade according to claim 1 , wherein the tip-thinning portion and the blade body are integrally formed by: (i) machining a metallic substrate, and (ii) covering only an outer surface of the metallic substrate constituting the blade body with a thermal barrier coating layer.

14. A gas turbine, comprising:
a turbine including a turbine rotor and a plurality of turbine blades according to claim 1 , the plurality of turbine blades being disposed on the turbine rotor in a circumferential direction and an axial direction;
a compressor configured to suction combustion air and to generate compressed air;
a combustor configured to inject fuel into the compressed air to burn the fuel and to generate combustion gas for driving the turbine; and
a casing including a ring segment facing the tip-thinning portion with a gap interposed therebetween, and being configured to accommodate the turbine rotor and the plurality of turbine blades.

15. The turbine blade according to claim 1 , wherein the position of the inner surface of the top plate faces the tip-thinning portion.

16. The turbine blade according to claim 1 , wherein the position of the inner surface of the top plate is closer to the suction-surface-side blade wall side of the top plate than a position of the inner surface of the top plate facing the tip-thinning portion.

17. The turbine blade according to claim 1 , wherein the outer surface of the top plate is configured to be parallel to the inner circumferential surface of the casing.

18. The turbine blade according to claim 1 , wherein the outer surface of the top plate is parallel to the inner surface of the top plate.

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Iida Koichiro
• Ito Ryuta

Classifications

• F05D2260/202

  by film cooling · CPC title

• F01D5/186

  Film cooling (F01D5/187 takes precedence) · CPC title

• F05D2220/32

  in gas turbines · CPC title

• F05D2240/307

  related to the tip of a rotor blade · CPC title

• F01D5/20 Primary

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