Aerodynamic Fuel Nozzle
The present application and the resultant patent provide a combustor for a turbine engine. The combustor may include a number of fuel nozzles with one or more of the fuel nozzles including a swirler assembly. The swirler assembly may include a number of stages with a number of fueled structures and a number of unfueled structures.
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The present application relates generally to gas turbine engines and more particularly relates to an aerodynamic fuel nozzle with a triple stage swirler for late lean injection and turndown.
BACKGROUND OF THE INVENTIONDry Low NOx technology may be applied for emissions control with gaseous fuel combustion in industrial gas turbines using annular can combustion systems and the like. These known Dry Low NOx combustion systems provide premixing of the fuel and the air for a generally uniform rate of combustion with relatively constant reaction zone temperatures. Through careful air management, these reaction zone temperatures may be optimized for very low production of nitrogen oxides (“NOx”), carbon monoxide (“CO”), unburned hydrocarbons (“UHC”), and other types of undesirable emissions. Specifically, the modulation of a center premix fuel nozzle may expand the range of operation by allowing the fuel-air ratio and the corresponding reaction rates of the outer nozzles to remain relatively constant while varying the fuel input into the turbine.
Fuel staging allows for higher turbine inlet temperatures with a uniform heat release. Axially staged systems generally employ multiple planes of fuel injection along the combustor flow path. Even with advances in materials and heat transfer methods, however, current combustor designs are challenged to produce low nitrogen oxide emissions at full load conditions. Likewise, carbon monoxide emissions at part load conditions pose a challenge in reducing combustion firing temperatures. By firing only selected nozzles, the adjacent unfired nozzles may quench the reaction and produce carbon monoxide. The fired nozzle also may cause significant thermal stresses in the combustor liner so as to reduce component life time.
There is thus a desire for improved fuel nozzle and combustor designs and/or methods of staging fuel therein so as to lower peak fuel temperatures. Such improved designs should maintain adequate system output and efficiency with correspondingly low production of nitrogen oxides, carbon monoxide, and other types of emissions.
SUMMARY OF THE INVENTIONThe present application and the resultant patent thus provide a combustor for a turbine engine. The combustor may include a number of fuel nozzles with one or more of the fuel nozzles including a swirler assembly. The swirler assembly may include a number of stages with a number of fueled structures and a number of unfueled structures.
The present application and the resultant patent further provide a method of operating a combustor for late lean injection. The method may include the steps of providing a flow of air to a fuel nozzle, providing a flow of fuel through one or more fueled structures of a swirler assembly, swirling the flow of air and the flow of fuel through multiple stages of the swirler assembly, establishing a primary recirculation zone about the fuel nozzle for low emissions, and establishing a secondary recirculation zone downstream of the fuel nozzle for high temperatures.
The present application and the resultant patent further provide a swirler assembly for use with a combustor. The swirler assembly may include a number of stages, a number of vanes, and a number of blocks. Each of the stages may include one or more of the vanes and/or the blocks.
These and other features and improvements of the present application and the resultant patent will become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.
Referring now to the drawings, in which like numerals refer to like elements throughout the several views,
The gas turbine engine 10 may use natural gas, various types of syngas, and/or other types of fuels. The gas turbine engine 10 may be any one of a number of different gas turbine engines such as those offered by General Electric Company of Schenectady, N.Y. and the like. The gas turbine engine 10 may have different configurations and may use other types of components. Other types of gas turbine engines also may be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment also may be used herein together.
A combustion zone 75 may be positioned within the outer casing 55 downstream of the end cover 60 and the fuel nozzles 65, 70. The combustion zone 75 may be enclosed via a combustion liner 80. A flow sleeve 85 may surround the combustion liner 80 and define a flow path 90 therebetween. The flow of air 20 from the compressor 15 flows through the flow path 90, reverses direction about the end cover 60, and flows into the fuel nozzle 65, 70. A transition piece 95 may extend about the downstream end of the outer casing 55. The transition piece 95 may be in communication with the turbine 10 for directing the flow of combustion gases 35 thereto. Other components and other configurations may be used herein.
The combustor 25 may be late lean injection compatible. A late lean injection compatible combustor may be any combustor with either an exit temperatures that exceeds about 2,500 degrees Fahrenheit (about 1,371 degrees Celsius) or handles fuels with components that are more reactive than, for example, methane with a hot side residence time greater than about 10 milliseconds. Examples of late lean injection compatible combustors include a DLN-1 (“Dry-Low NOx”) combustor, a DLN-2 combustor, and a DLN-2.6 combustor offered by General Electric Company of Schenectady, N.Y. , Other types of late lean injection compatible combustors may be used herein. Such late lean injection compatible combustors may have a number of fuel injectors (not shown) positioned about the transition piece 95 or otherwise for fuel staging and the like. These downstream fuel injectors, however, may increase the overall complexity of the combustor 25. Other components and other configurations may be used herein.
The stages 140 of the swirler assembly 130 may take many different forms. For example, the swirlers 130 may include a number of radial vanes 200 as is shown in
Combinations of the vanes 200 and the blocks 210 may be used together. Specifically, different types of swirlers with different types of vanes 200, blocks 210, or other shapes may be used herein. The following chart shows several examples of differing embodiments of the swirler assemblies 130:
The examples shown herein are not exclusive. As one can appreciate, any number of different combinations of vanes 200 and blocks 210 being fueled or unfueled may be used herein.
The fuel nozzle 110 thus creates a primary recirculation zone 260 near the nozzle 120 and a secondary recirculation zone 270 downstream. With late lean injection operations, the primary recirculation zone 260 operates near the flammability limits (about Phi˜2.5 or about Phi˜0.4) and the combustion products travel downstream without forming significant nitrogen oxides or other emissions. In the secondary recirculation zone 270, the core and tertiary air mix at overall lean conditions and raise the overall temperature of the hot combustion gases so as to reduce fuel staging aerodynamic means.
For high turndown, the primary recirculation zone 260 may be fired at moderately lean temperatures (about Phi˜0.5 to 0.6). This may accomplish good fuel burnout and maintain low emissions. Further downstream, the inner products mix with the tertiary stream in the secondary recirculation zone 270 so as to bring the mixture to overall lean conditions. The fuel nozzle 110 thus is able to form turndown while maintaining low carbon monoxide in the presence of unfired nozzles.
The nozzle 110 thus enables increased combustion firing temperatures without increasing nitrogen oxides by effectively implementing late lean injection performance without significant hardware changes. The nozzle 110 also enables high combustion turndown without producing significant levels of carbon monoxide. The nozzle 110 may be used in conjunction with existing nozzles that may remain unfired without impacting on the low carbon monoxide performance.
The use of the swirler assembly 130 with a center nozzle 120 thus provides fuel staging so as to create a downstream aero-staged flame. Fuel staging herein thus may be maximized. Moreover, such fuel staging may dampen combustion dynamics.
It should be apparent that the foregoing relates only to certain embodiments of the present application and the resultant patent. Numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.
Claims
1. A combustor for a turbine engine, comprising:
- a plurality of fuel nozzles; and
- one or more of the plurality of fuel nozzles comprising a swirler assembly;
- wherein the swirler assembly comprises a plurality of stages; and
- wherein the plurality of stages comprises a plurality of fueled structures and a plurality of unfueled structures.
2. The combustor of claim 1, wherein the plurality of fuel nozzles comprises a central fuel nozzle.
3. The combustor of claim 1, wherein the plurality of stages comprises a first stage, a second stage, and a third stage.
4. The combustor of claim 1, wherein the plurality of stages extend in an axial direction.
5. The combustor of claim 1, wherein the plurality of stages extend in a circumferential direction.
6. The combustor of claim 1, wherein the plurality of stages comprises a plurality of radial vanes.
7. The combustor of claim 1, wherein the plurality of stages comprises a plurality of blocks.
8. The combustor of claim 7, wherein the plurality of blocks comprises a plurality of fixed blocks and a plurality of movable blocks.
9. The combustor of claim 1, wherein the plurality of fueled structures comprises a plurality of radial vanes and a plurality of blocks.
10. The combustor of claim 1, wherein the plurality of fueled structures comprises a plurality of injection ports.
11. The combustor of claim 10, wherein the plurality of injection ports comprises an axial direction and/or a circumferential direction.
12. The combustor of claim her comprising a primary recirculation zone about the plurality of fuel nozzles and a secondary recirculation zone downstream of the plurality of fuel nozzles.
13. The combustor of claim 1, wherein the plurality of fueled structures comprises a plurality of vanes.
14. The combustor of claim 1, wherein the plurality of fueled structures comprises a plurality of movable blocks.
15. A method of operating a combustor for late lean injection, comprising:
- providing a flow of air to a fuel nozzle;
- providing a flow of fuel through one or more fueled structures of a swirler assembly;
- swirling the flow of air and the flow of fuel through multiple stages of the swirler assembly;
- establishing a primary recirculation zone about the fuel nozzle for low emissions; and
- establishing a secondary recirculation zone downstream of the fuel nozzle for high temperatures.
16. The method of claim 15, wherein the step of establishing a primary recirculation zone comprises combusting the flow of fuel and the flow of air near a flammability limit.
17. The method of claim 15, wherein the step of establishing a primary recirculation zone comprises combusting the flow of fuel and the flow of air without forming nitrogen oxides.
18. The method of claim 15, wherein the step of establishing a secondary recirculation zone comprises lean mixing of the flow of fuel and the flow of air.
19. The method of claim 15, wherein the step of establishing a secondary recirculation zone downstream of the fuel nozzle for high temperatures comprises combusting the flow of fuel and the flow of air at higher combustion temperatures as compared to the primary recirculation zone.
20. A swirler assembly for use with a combustor, comprising:
- a plurality of stages;
- a plurality of vanes; and
- a plurality of blocks;
- wherein each of the plurality of stages comprises one or more of the plurality of vanes and/or one more of the plurality of blocks.
Type: Application
Filed: Apr 22, 2011
Publication Date: Oct 25, 2012
Applicant: GENERAL ELECTRIC COMPANY (Schnectady, NY)
Inventor: Joel Meier Haynes (Niskayuna, NY)
Application Number: 13/092,345
International Classification: F23R 3/28 (20060101); F23R 3/26 (20060101);