LATE LEAN INJECTION SYSTEM
A late lean injection system includes at least one fuel injector disposed proximate a combustion zone. Also included is at least one guide for directing an airflow from a region proximate a compressor discharge exit to the at least one fuel injector.
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The subject matter disclosed herein relates to turbines, and more particularly to late lean injection systems.
BRIEF DESCRIPTION OF THE INVENTIONAccording to one aspect of the invention, a late lean injection system includes at least one fuel injector disposed proximate a combustion zone. Also included is at least one guide for directing an airflow from a region proximate a compressor discharge exit to the at least one fuel injector.
According to another aspect of the invention, a late lean injection system includes a transition duct defining a transition interior, the transition duct having an end adapted for connection to a first turbine zone, and an opposite end. Also included is a sleeve spaced radially outward of the transition duct and extending circumferentially around the transition duct. Further included is at least one fuel injector configured to inject fuel into the transition interior. Yet further included is at least one guide for directing an airflow to the at least one fuel injector.
According to yet another aspect of the invention, a late lean injection system includes a transition duct having an upstream end and a downstream end. Also included is a liner duct disposed proximate the upstream end of the transition duct. Further included is a flowsleeve spaced radially outward of the liner duct and extending circumferentially around the liner duct. Yet further included is at least one fuel injector disposed proximate at least one of the transition duct and the liner duct. Also included is at least one guide for directing an airflow from a region proximate a compressor discharge exit to the at least one fuel injector.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
DETAILED DESCRIPTION OF THE INVENTIONReferring to
The combustor of the gas turbine is late lean injection (LLI) compatible. An LLI compatible combustor is any combustor with either an exit temperature that exceeds 2500° F. or handles fuels with components that are more reactive than methane with a hot side residence time greater than 10 milliseconds (ms).
Referring to
Referring to
Irrespective of the embodiment employed in the gas turbine system, a plurality of fuel injectors 18 are each integrated with or structurally supported by a plurality of housings that extend radially into at least one of the transition duct 12 or the liner duct 16. The plurality of fuel injectors 18 extend through the respective duct, i.e., the transition duct 12 or the liner duct 16, to varying depths. That is, the fuel injectors 18 are each configured to supply a second fuel (i.e., LLI fuel) to the combustion zone through fuel injection in a direction that is generally transverse to a predominant flow direction through the transition duct 12 and/or the liner duct 16. For each of the above-described embodiments, it is emphasized that the plurality of fuel injectors 18 may be disposed proximate the transition duct 12 or the liner duct 16, in spite of the illustrated embodiments showing disposal of the plurality of fuel injectors 18 disposed in connection with only one of the transition duct 12 and the liner duct 16. Furthermore, the plurality of fuel injectors 18 may be disposed in connection with both the transition duct 12 and the liner duct 16. The plurality of fuel injectors 18 may be disposed in a single axial circumferential stage that includes multiple currently operating fuel injectors 18 respectively disposed around a circumference of a single axial location of the transition duct 12 and/or the liner duct 16. It is also conceivable that the plurality of fuel injectors 18 may be situated in a single axial stage, multiple axial stages, or multiple axial circumferential stages. A single axial stage includes a currently operating single fuel injector 18. A multiple axial stage includes multiple currently operating fuel injectors 18 that are respectively disposed at multiple axial locations. A multiple axial circumferential stage includes multiple currently operating fuel injectors 18, which are disposed around a circumference of the transition duct 12 and/or the liner duct 16 at multiple axial locations thereof.
Airflow from a compressor enters into a compressor discharge casing 32. A high pressure dynamic airflow 20 exits the compressor discharge casing 32 proximate a compressor discharge exit 34 and rushes downstream toward the transition duct 12 and/or the liner duct 16 to locations proximate the fuel injectors 18. To reduce the pressure drop of airflow within the fuel injectors 18, where mixing of the air and LLI fuel occurs and penetrates into the transition duct 12 and/or the liner duct 16, it is advantageous to harness the high pressure dynamic airflow 20 into the fuel injectors 18.
Referring to
Irrespective of the exact shape of the guide 22, the guides 22 may be attached individually proximate the impingement sleeve 14 and/or flowsleeve 17, or the transition duct 12 in the case of the embodiment illustrated in
Referring to
In operation, airflow is channeled toward the fuel injectors 18 by the guides 22 that project out into the high pressure dynamic airflow 20 passing the impingement sleeve 14 and/or the flowsleeve 17 of the transition duct 12 and/or the liner duct 16. The guides 22, by a combination of stagnation and redirection, catch air that would previously have passed the apertures 24 aligned with the fuel injectors 18 due to the lack of static pressure differential to drive the flow through them, and directs the airflow 20 inward into the fuel injectors 18 to mix with LLI fuel, and into the transition duct 12 and/or the liner duct 16, thus producing deeper penetration into the combustion zone.
Referring now to
The contour of the guides 122 as they extend from the first end 130 to the second end 132 may vary based on the specific application of use. One typical contour comprises a substantially elongated straight portion 136 extending from a region proximate the first end 130 and a bend portion 128 that functions to transition the airflow 120 from the substantially elongated straight portion 136 to the inlet 134 of the fuel injector 118. As with the scoop guides 22, such a bend portion 128 may impose turning vortices on the airflow. To reduce the occurrence of such vortices, the bend portion 128 may include one or more straightening vanes 126.
Referring to
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
Claims
1. A late lean injection system comprising:
- at least one fuel injector disposed proximate a combustion zone; and
- at least one guide for directing an airflow from a region proximate a compressor discharge exit to the at least one fuel injector.
2. The late lean injection system of claim 1, further comprising a transition duct.
3. The late lean injection system of claim 2, wherein the at least one fuel injector is disposed proximate the transition duct and is configured to inject a fuel into the combustion zone.
4. The late lean injection system of claim 2, further comprising a liner duct, wherein the at least one fuel injector is disposed proximate the liner duct and is configured to inject a fuel into the combustion zone.
5. The late lean injection system of claim 1, wherein the at least one guide includes a first end disposed proximate the compressor discharge exit and a second end disposed proximate the at least one fuel injector.
6. The late lean injection system of claim 1, wherein the at least one guide comprises a bend proximate the at least one fuel injector.
7. The late lean injection system of claim 6, wherein the at least one guide comprises at least one straightening vane proximate the bend.
8. The late lean injection system of claim 1, wherein the at least one guide is operably connected to a compressor discharge casing.
9. The late lean injection system of claim 1, further comprising a plurality of fuel injectors, wherein the plurality of fuel injectors are circumferentially spaced at a single axial location.
10. The late lean injection system of claim 1, further comprising a plurality of fuel injectors, wherein the plurality of fuel injectors are circumferentially spaced a plurality of axial locations.
11. A late lean injection system comprising:
- a transition duct defining a transition interior, the transition duct having an end adapted for connection to a first turbine zone, and an opposite end;
- a sleeve spaced radially outward of the transition duct and extending circumferentially around the transition duct;
- at least one fuel injector configured to inject fuel into the transition interior; and
- at least one guide for directing an airflow to the at least one fuel injector.
12. The late lean injection system of claim 11, wherein the at least one guide includes a first end disposed proximate a compressor discharge exit and a second end disposed proximate the at least one fuel injector.
13. The late lean injection system of claim 12, further comprising a liner duct disposed proximate the opposite end of the transition duct.
14. The late lean injection system transition piece of claim 11, wherein the at least one guide comprises a bend proximate the at least one fuel injector.
15. The late lean injection system transition piece of claim 14, wherein the at least one guide comprises at least one straightening vane proximate the bend.
16. The late lean injection system transition piece of claim 12, wherein the at least one guide is operably connected to a compressor discharge casing.
17. A late lean injection system comprising:
- a transition duct having an upstream end and a downstream end;
- a liner duct disposed proximate the upstream end of the transition duct;
- a flowsleeve spaced radially outward of the liner duct and extending circumferentially around the liner duct;
- at least one fuel injector disposed proximate at least one of the transition duct and the liner duct; and
- at least one guide for directing an airflow from a region proximate a compressor discharge exit to the at least one fuel injector.
18. The late lean injection system of claim 17, wherein the at least one guide includes a first end disposed proximate the compressor discharge exit and a second end disposed proximate the at least one fuel injector.
19. The late lean injection system of claim 17, wherein the at least one guide comprises a bend proximate the at least one fuel injector.
20. The late lean injection system of claim 17, wherein the at least one guide is operably connected to a compressor discharge casing.
Type: Application
Filed: Feb 16, 2012
Publication Date: Aug 22, 2013
Applicant: GENERAL ELECTRIC COMPANY (Schenectady, NY)
Inventor: Patrick Benedict Melton (Horse Shoe, NC)
Application Number: 13/398,630