Fuel-air mixing system with mixing chambers of various lengths for gas turbine system

Patent metadata

Field	Value
Publication number	US-9650959-B2
Application number	US-201313797848-A
Country	US
Kind code	B2
Filing date	Mar 12, 2013
Priority date	Mar 12, 2013
Publication date	May 16, 2017
Grant date	May 16, 2017

Abstract

Embodiments of the present disclosure are directed to systems and methods for premixing fuel and air prior to combustion within a combustion chamber. The system includes a plurality of fuel injectors and a plurality of mixing tubes, wherein each mixing tube has a first portion for receiving one of the plurality of fuel injectors and a second portion having a mixing chamber that is configured to mix fuel and air. The length of the mixing chamber varies among the plurality of mixing tubes to allow for different mixing times.

First claim

The invention claimed is:

1. A premixing system for a gas turbine engine, the premixing system comprising:
a plurality of fuel injectors;
a plurality of mixing tubes, each mixing tube comprising:
an annular wall defining the mixing tube and comprising a plurality of apertures configured to enable air to flow radially into the mixing tube;
a first portion configured to receive one of the plurality of fuel injectors, wherein the one fuel injector of the plurality of fuel injectors is positioned coaxially within the first portion of the mixing tube; and
a second portion comprising a mixing chamber configured to mix fuel provided via one or more holes formed in the one fuel injector and the air, wherein the mixing chamber is defined by and extends between a tip of the one fuel injector and a second and of the mixing tube that is configured to deposit the fuel and the air directly into a combustion chamber of the gas turbine engine, wherein the fuel injector having a first end and the tip of the one fuel injector disposed at an opposite downstream end of the one fuel injector and the one or more holes are positioned upstream of the tip of the one fuel injector; wherein a respective length of the respective mixing chamber varies among the plurality of mixing tubes.

2. The system of claim 1 , wherein the plurality of mixing tubes are of substantially similar length.

3. The system of claim 2 , wherein a ratio between a first length of the first portion and a second length of the second portion varies among the plurality of mixing tubes.

4. The system of claim 1 , wherein at least two of the plurality of fuel injectors have different lengths.

5. The system of claim 1 , wherein the plurality of apertures formed on the respective annular wall of a first mixing tube of the plurality of mixing tube are the only apertures formed on the respective annular wall of the first mixing tube of the plurality of mixing tubes that are configured to enable air to flow radially into the first mixing tube, the plurality of apertures formed on the respective annular wall of the first mixing tube are positioned a first distance away from a first outlet of the first mixing tube, and the plurality of apertures formed on the respective annular wall of a second mixing tube of the plurality of mixing tubes are the only apertures formed on the respective annular wall of the second mixing tube of the plurality of mixing tubes that are configured to enable air to flow radially into the second mixing tube, and the plurality of apertures formed on the respective annular wall of the second mixing tube are positioned a second distance away from a second outlet of the second mixing tube, wherein the first and second distances are different.

6. The system of claim 5 , wherein each of the plurality of fuel injectors comprises one or more holes configured to inject fuel directly into the respective mixing tube, and the respective one or more holes of a first fuel injector of the plurality of fuel injectors are the only holes formed in the first fuel injector that are configured to inject fuel directly into the first mixing tube, the respective one or more holes of the first fuel injector are positioned at a third distance from the first outlet of the first mixing tube, the respective one or more holes of a second fuel injector of the plurality of fuel injectors are the only holes formed in the second fuel injector that are configured to inject fuel directly into the second mixing tube, and the respective one or more holes of the second fuel injector are positioned at a fourth distance from the second outlet of the second mixing tube, and the third and fourth distances are different.

7. The system of claim 1 , wherein the respective second ends of each of the plurality of mixing tubes are substantially aligned in a plane.

8. The system of claim 1 , wherein the plurality of apertures are positioned upstream of the one or more holes.

9. The system of claim 1 , wherein the plurality of apertures are the only apertures formed on the annular wall of each mixing tube that are configured to enable air to flow radially into each mixing tube, the one or more holes are the only holes formed in the one fuel injector, and an axial distance between the plurality of apertures and the one or more holes is constant among the plurality of mixing tubes.

10. The system of claim 1 , wherein a respective axial distance between the tip and the one or more holes is constant among the plurality of fuel injectors.

11. A gas turbine system comprising:
a combustor comprising:
a combustion chamber;
a plurality of fuel injectors;
a plurality of mixing tubes, each mixing tube comprising:
an annular wall defining the mixing tube and comprising a plurality of apertures configured to enable air to flow radially into the mixing tube, wherein the plurality of apertures are positioned in a section of the annular wall that extends along part of an axial length of the annular wall and the remainder of the annular wall outside of the section is devoid of apertures that are configured to enable air to flow radially into the mixing tube;
a first portion configured to receive one of the plurality of fuel injectors; and
a second portion downstream of the first portion and comprising a mixing chamber configured to mix fuel provided by the one fuel injector of the plurality of fuel injectors and the air;

wherein the respective mixing chamber of a first mixing tube of the plurality of mixing tubes has a different length than the respective mixing chamber of a second mixing tube of the plurality of the mixing tubes;
wherein the respective section of the first mixing tube is positioned a first distance away from the combustion chamber, and the respective section of the second mixing tube is positioned a second distance away from the combustion chamber, and the first and second distances are different from one another.

12. The system of claim 11 , wherein the plurality of mixing tubes are of substantially similar length.

13. The system of claim 11 , wherein at least two fuel injectors of the plurality of fuel injectors have different lengths.

14. The system of claim 11 , wherein each of the plurality of mixing tubes extends between a first end and a second end, wherein the first end is configured to receive the one fuel injector and the second end is configured to deposit a fuel-air mixture directly into the combustion chamber.

15. The system of claim 11 , wherein each of the plurality of fuel injectors comprises one or more holes configured to inject fuel into the respective mixing tube, and the respective one or more holes of a first fuel injector of the plurality of fuel injectors are the only holes formed in the first fuel injector that are configured to inject fuel directly into the first mixing tube, the respective one or more holes of the one of the plurality of mixing injectors are positioned at a third distance from the combustion chamber and the respective one or more holes of the another of the plurality of fuel injectors are the only holes formed in the another of the plurality of fuel injectors, and the respective one or more holes of the another fuel injector are positioned at a fourth distance different from the third distance from the combustion chamber.

16. The system of claim 11 , wherein each fuel injector of the plurality of fuel injectors comprises one or more holes configured to flow the fuel from the respective fuel injector into the respective mixing chamber, the respective one or more holes are the only holes formed in the respective fuel injector that are config

Assignees

• Gen Electric

Inventors

• Boardman Gregory Allen
• Melton Patrick Benedict
• Westmoreland James Harold
• Chila Ronald James
• Crothers Sarah Lori

Classifications

• F02C7/22 Primary

  Fuel supply systems · CPC title

• F23D14/64

  with injectors · CPC title

• F23D14/62

  Mixing devices; Mixing tubes · CPC title

• Y02T50/675

  Cross-Sectional Technologies · mapped topic

• F23R3/286

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