Systems and methods for varying a throat area between adjacent buckets in a turbine for improved part load performance

Patent metadata

Field	Value
Publication number	US-9771805-B2
Application number	US-201314080447-A
Country	US
Kind code	B2
Filing date	Nov 14, 2013
Priority date	Nov 14, 2013
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

A gas or steam turbine is disclosed herein. The turbine may include a throat area formed between adjacent buckets. The turbine also may include a variable throat device associated with at least one of the adjacent buckets. The variable throat device may be configured to vary the throat area between the adjacent buckets for improved part load performance.

First claim

That which is claimed:

1. A gas or steam turbine, comprising:
adjacent buckets comprising a first bucket and a second bucket, wherein the first bucket and the second bucket each comprise a leading edge, a trailing edge, a pressure side, and a suction side;
a throat area formed within a passage between the adjacent buckets, wherein the throat area comprises the shortest distance from the trailing edge of the first bucket to the suction side of the second bucket; and
a variable throat device comprising a bi-metallic strip disposed at the throat area on the suction side of the second bucket between the leading edge and trailing edge of the second bucket and directly opposite the trailing edge of the first bucket, wherein the variable throat device is configured to bulge towards and contract away from the trailing edge of the first bucket to vary the throat area between the adjacent buckets for improved part load performance.

2. The turbine of claim 1 , wherein the bi-metallic strip is formed from one or more layers of bi-metallic materials with different coefficients of thermal expansion.

3. The turbine of claim 1 , wherein the adjacent buckets comprise last stage buckets.

4. The turbine of claim 1 , wherein the variable throat device is at least partially controlled by an external source of air or compressor extraction air.

5. A gas or steam turbine system, comprising:
a compressor;
a combustion system in communication with the compressor; and
a turbine in communication with the combustion system, wherein the turbine comprises:
adjacent buckets comprising a first bucket and a second bucket, wherein the first bucket and the second bucket each comprise a leading edge, a trailing edge, a pressure side, and a suction side;
a throat area formed within a passage between the adjacent buckets, wherein the throat area comprises the shortest distance from the trailing edge of the first bucket to the suction side of the second bucket; and
a variable throat device comprising a bi-metallic strip disposed at the throat area on the suction side of the second bucket between the leading edge and trailing edge of the second bucket and directly opposite the trailing edge of the first bucket, wherein the variable throat device is configured to bulge towards and contract away from the trailing edge of the first bucket to vary the throat area between the adjacent buckets for improved part load performance.

6. The system of claim 5 , wherein the bi-metallic strip is formed from one or more layers of bi-metallic materials with different coefficients of thermal expansion.

7. The system of claim 5 , wherein the adjacent buckets comprise last stage buckets.

8. A gas or steam turbine, comprising:
adjacent buckets comprising a first bucket and a second bucket, wherein the first bucket and the second bucket each comprise a leading edge, a trailing edge, a pressure side, and a suction side;
a throat area formed within a passage between the adjacent buckets, wherein the throat area comprises the shortest distance from the trailing edge of the first bucket to the suction side of the second bucket; and
a bi-metallic strip disposed at the throat area on a suction side of the second bucket between the leading edge and trailing edge of the second bucket and directly opposite the trailing edge of the first bucket, wherein the bi-metallic strip is configured to bulge towards and contract away from the trailing edge of the first bucket to vary the throat area between the adjacent buckets for improved part load performance, wherein the bi-metallic strip is at least partially controlled by an external source of air or compressor extraction air.

Assignees

• Gen Electric

Inventors

• Subramaniyan Moorthi
• Doss Jeyamani
• Deodhar Subodh Diwakar

Classifications

• F01D17/162

  for axial flow, i.e. the vanes turning around axes which are essentially perpendicular to the rotor centre line (F01D17/167 takes precedence) · CPC title

• F05D2300/505

  Shape memory behaviour · CPC title

• F05D2300/50212

  dissimilar · CPC title

• F01D7/00

  Rotors with blades adjustable in operation; Control thereof (for reversing F01D1/30) · CPC title

• F01D5/148 Primary

  Blades with variable camber, e.g. by ejection of fluid · CPC title