Fuel-air premixer for a gas turbine

Patent metadata

Field	Value
Publication number	US-2017102147-A1
Application number	US-201514879793-A
Country	US
Kind code	A1
Filing date	Oct 9, 2015
Priority date	Oct 9, 2015
Publication date	Apr 13, 2017
Grant date	—

Abstract

The present disclosure relates to a fuel-air premixer for a turbine system. The fuel-air premixer includes a swirler and a centerbody. The swirler is configured to direct a flow of air through the premixer, and the centerbody is configured to inject fuel into the flow of air. Additionally, the centerbody includes an airfoil shape that reduces and/or substantially eliminates recirculation pockets to prevent autoignition and/or flame holding in a combustion chamber. Accordingly, the turbine system may produce fewer NO x emissions.

First claim

1 . A fuel-air premixer for a gas turbine, comprising:
a dual counter-rotating swirler comprising a first rotor and a second rotor, wherein the first rotor and the second rotor are configured to spin about a shaft and the dual counter-rotating swirler is configured to direct a flow of air in a downstream direction; and a centerbody coupled to the dual counter-rotating swirler via the shaft, wherein the centerbody comprises first fuel orifices on a surface of the centerbody, the first fuel orifices are configured to inject fuel into the flow of air to create a fuel-air mixture, and the centerbody comprises an airfoil shape configured to reduce or eliminate formation of a recirculation pocket when in use.

2 . The fuel-air premixer of claim 1 , wherein the fuel-air mixture is configured to be received by a combustor.

3 . The fuel-air premixer of claim 2 , wherein the airfoil shape of the centerbody is configured to prevent one or both of autoignition and flame holding in the combustor.

4 . The fuel-air premixer of claim 2 , wherein the combustor is configured to emit an exhaust gas comprising a NOx concentration of less than 25 parts per million (ppm).

5 . The fuel-air premixer of claim 1 , wherein the first fuel orifices comprise a teardrop shape.

6 . The fuel-air premixer of claim 1 , wherein no recirculation pocket forms between the centerbody and the fuel air mixture when in use.

7 . The fuel-air premixer of claim 1 , wherein the airfoil shape comprises a leading edge and a trailing edge, wherein the leading edge is upstream of the trailing edge.

8 . The fuel-air premixer of claim 7 , wherein a diameter of the centerbody increases and then decreases when moving from the leading edge to the trailing edge.

9 . The fuel-air premixer of claim 7 , wherein the first fuel orifices are positioned closer to the leading edge than the trailing edge.

10 . A fuel-air premixer for a gas turbine, comprising:
an airfoil-shaped centerbody coupled to a swirler and comprising a cross-section having an upper surface, a lower surface, a leading edge, and a trailing edge, wherein the leading edge is upstream of the trailing edge with respect to a flow of a fuel-air mixture, and the fuel-air mixture is configured to substantially conform to the upper surface and the lower surface such that a recirculation pocket is absent when in use.

11 . The fuel-air premixer of claim 10 , wherein the fuel-air mixture is configured to be received by a combustor.

12 . The fuel-air premixer of claim 11 , wherein the airfoil shape of the centerbody is configured to prevent one or both of autoignition and flame holding in the combustor.

13 . The fuel-air premixer of claim 11 , wherein the combustor is configured to emit an exhaust gas comprising a NOx concentration of less than 25 parts per million (ppm).

14 . The fuel-air premixer of claim 10 , wherein a thickness of the air-foil shaped centerbody varies along the cross-section from the leading edge to the trailing edge.

15 . The fuel-air premixer of claim 10 , wherein the airfoil-shaped centerbody comprises fuel orifices configured to mix a fuel with air to form the fuel-air mixture.

16 . A method, comprising:
compressing a stream of air with a compressor; pre-mixing the stream of air with a fuel in a premixer having an airfoil centerbody; mixing the stream of air and the fuel in a mixer to form a substantially homogenous fuel-air mixture; combusting the substantially homogenous fuel-air mixture in a combustion chamber to form an exhaust gas; and emitting the exhaust gas to a surrounding environment.

17 . The method of claim 16 , wherein the exhaust gases comprise a NO x concentration of less than 25 parts per million (ppm).

18 . The method of claim 16 , wherein the airfoil centerbody substantially blocks formation of a recirculation pocket in the premixer.

19 . The method of claim 18 , wherein blocking formation of the recirculation pocket prevents autoignition and flame holding in the combustion chamber.

20 . The method of claim 16 , wherein combusting the substantially homogenous fuel-air mixture rotates one or more blades of a turbine.

Assignees

• Gen Electric

Inventors

• Wang Liangyu
• Dean Anthony John
• Mcmanus Keith Robert
• Singh Kapil Kumar
• Li Suhui
• Kapilavai Sravan Kumar Dheeraj
• Thariyan Mathew Paul
• Graham Owen

Classifications

• F05D2260/14

  Preswirling · CPC title

• F02C7/222

  Fuel flow conduits, e.g. manifolds · CPC title

• F23R3/14 Primary

  by using swirl vanes · CPC title

• F05D2220/32

  in gas turbines · CPC title

• F23R3/286 Primary

  having fuel-air premixing devices (F23R3/30 takes precedence) · CPC title