Gas turbine

Patent metadata

Field	Value
Publication number	US-11028699-B2
Application number	US-201916239524-A
Country	US
Kind code	B2
Filing date	Jan 3, 2019
Priority date	Feb 9, 2018
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A gas turbine includes a housing in which combustion gas flows; a rotor section rotatably installed in the housing; and a turbine blade configured to rotate the rotor section by receiving a rotational force from the combustion gas and to be cooled by a cooling fluid flowing in a cooling path, the turbine blade including a tip side provided with tip cooling holes through which a portion of the cooling fluid in the cooling path is discharged from the turbine blade. The tip cooling holes include a first tip cooling hole formed in a pressure surface of the turbine blade, and a second tip cooling hole formed in a suction surface of the turbine blade. The gas turbine can easily maintain a gap between the tip side of the turbine blade and an inner circumferential surface of the housing, preventing degradation of the turbine blade efficiency.

First claim

What is claimed is:

1. A gas turbine comprising:
a housing in which combustion gas flows;
a rotor section rotatably installed in the housing;
a turbine blade configured to rotate the rotor section by receiving a rotational force from the combustion gas and to be cooled by a cooling fluid flowing in a cooling path, the turbine blade including a tip side provided with a plurality of tip cooling holes through which a portion of the cooling fluid in the cooling path is discharged from the turbine blade, the tip side of the turbine blade forming a tip gap with respect to an inner circumferential surface of the housing through which leakage gas flows from a pressure surface of the turbine blade to a suction surface of the turbine blade; and
a squealer rib extending centrifugally from the tip side of the turbine blade, between an end surface of the turbine blade and the suction surface of the turbine blade,
wherein the squealer rib includes:
an upper rib surface spaced apart from the end surface of the turbine blade,
an outer rib surface that is substantially perpendicular to the end surface of the turbine blade and extends in a radial direction continuously relative to the suction surface of the turbine blade, the outer rib surface extending radially at a slope equal to that of a radially outer portion of the suction surface of the turbine blade, and
an inner rib surface forming a back surface of the outer rib surface and extending between the end surface of the turbine blade and the upper rib surface,

wherein the cooling path of the turbine blade includes a first inner wall formed opposite to an outer portion of the pressure surface of the turbine blade, a second inner wall formed opposite to an outer portion of the suction surface of the turbine blade to be parallel to the first inner wall, and a third inner wall that is substantially perpendicular to the first and second inner walls and connects the first and second walls at a radially outer end of the cooling path,
wherein the plurality of tip cooling holes include:
a first tip cooling hole formed in the pressure surface of the turbine blade so as to communicate with the first inner wall of the cooling path at a first communication point along the first inner wall and configured to discharge the cooling fluid and form a first air curtain for reducing the flow of the leakage gas through the tip gap, and
a second tip cooling hole formed in the squealer rib so as to communicate with the third inner wall of the cooling path at a second communication point along the second inner wall and configured to discharge the cooling fluid and form a second air curtain for further reducing the flow of the leakage gas through the tip gap, the second tip cooling hole extending through the turbine blade from the cooling path to the upper rib surface, the second air curtain formed by an outlet of the second tip cooling hole that faces the inner circumferential surface of the housing and is disposed downstream from an outlet of the first tip cooling hole,

wherein the first and third inner walls communicate with each other at a first perpendicular junction, the first perpendicular junction including a first surface portion of the first inner wall and a second surface portion of the third inner wall, the first surface portion including a flat surface extending from the first perpendicular junction to the first communication point, and
wherein the second and third inner walls communicate with each other at a second perpendicular junction, the second perpendicular junction including a third surface portion of the second inner wall and a fourth surface portion of the third inner wall, the fourth surface portion including a flat surface extending from the second perpendicular junction to the second communication point.

2. The gas turbine of claim 1 , wherein the tip side of the turbine blade includes a first inclined surface (S 1 ) for facilitating the formation of the first tip cooling hole.

3. The gas turbine of claim 1 , wherein the tip side of the turbine blade includes a first inclined surface (S 1 ) formed between an end surface of the turbine blade and the pressure surface of the turbine blade, such that the first inclined surface is inclined with respect to each of the end surface and the pressure surface.

4. The gas turbine of claim 3 , wherein the first tip cooling hole extends through the turbine blade from the cooling path to the first inclined surface (S 1 ).

5. The gas turbine of claim 3 , wherein the first tip cooling hole extends in a direction perpendicular to the first inclined surface (S 1 ).

6. The gas turbine of claim 3 , wherein the tip side of the turbine blade includes a second inclined surface (S 2 ) for facilitating the formation of the second tip cooling hole.

7. The gas turbine of claim 3 , wherein the inner rib surface of the squealer rib includes a second inclined surface (S 2 ) formed between the end surface and the upper rib surface such that the second inclined surface is inclined with respect to each of the end surface and the upper rib surface.

8. The gas turbine of claim 7 , wherein the second inclined surface (S 2 ) is spaced apart from the second tip cooling hole.

9. The gas turbine of claim 7 , wherein the second tip cooling hole extends in a direction parallel to the second inclined surface (S 2 ).

10. The gas turbine of claim 6 , wherein the inner rib surface is parallel to the outer rib surface and is spaced apart from the second tip cooling hole.

11. A gas turbine comprising:
a housing in which combustion gas flows;
a rotor section rotatably installed in the housing; and
a turbine blade configured to rotate the rotor section by receiving a rotational force from the combustion gas and to be cooled by a cooling fluid flowing in a cooling path, the turbine blade including
a tip side provided with a plurality of tip cooling holes through which a portion of the cooling fluid in the cooling path is discharged from the turbine blade,
an inclined surface (S 1 , S 2 ) for facilitating formation of the plurality of tip cooling holes, and
a squealer rib extending centrifugally from the tip side of the turbine blade, between an end surface of the turbine blade and a suction surface of the turbine blade,
wherein the tip side of the turbine blade includes an inclined surface (S 1 ) formed between the end surface of the turbine blade and the pressure surface of the turbine blade, such that the surface is inclined with respect to each of the end surface and the pressure surface,

wherein the cooling path of the turbine blade includes a first inner wall formed opposite to an outer portion of the pressure surface of the turbine blade, a second inner wall formed opposite to an outer portion of the suction surface of the turbine blade to be parallel to the first inner wall, and a third inner wall that is substantially perpendicular to the first and second inner walls and connects the first and second walls at a radially outer end of the cooling path,
wherein the plurality of tip cooling holes include:
a first tip cooling hole formed in a pressure surface of the turbine blade to communicate with the first inner wall of the cooling path at a first communication point along the first inner wall, the first tip cooling hole extending through the turbine blade from the cooling path to the inclined surface (S 1 ), and
a second tip cooling hole formed in the squealer rib to communicate with the third inner wall of the cooling path at a second communication point along the second inner wall,

wherein the first tip cooling hole forms an air curtain with a cooling fluid discharged from the first tip cooling hole, so that leakage gas flowing fro

Assignees

• Doosan Heavy Ind & Construction Co Ltd
• Doosan Heavy Ind Constr Co Ltd

Inventors

• Lee Jae Bin

Classifications

• F05D2260/202

  by film cooling · CPC title

• F05D2240/307

  related to the tip of a rotor blade · CPC title

• F01D5/186 Primary

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

• F02C7/18

  the medium being gaseous, e.g. air {(F02C7/125 takes precedence)} · CPC title

• F05D2260/22141

  using fins or ribs · CPC title