COMBUSTOR WITH ANNULAR BLUFF BODY
The present invention relates to a gas turbine combustor comprising: a flow sleeve; a combustion liner located at least partially within the flow sleeve thereby creating a main passage between the flow sleeve and the combustor liner; a dome located forward of the flow sleeve and encompassing at least a part of the combustion liner, the dome having a substantially rounded head end thereby forming a turning passage between the liner and the head end; and a swirler wall aligned along a centerline of the combustor, the swirler wall projecting into the liner, wherein the swirler wall and the rounded head end are connected, wherein the connection forms an annular end face.
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The present invention relates generally to a system and method for improving combustion stability in a gas turbine combustor.
BACKGROUNDIn an effort to reduce the amount of pollution emissions from gas-powered turbines, governmental agencies have enacted numerous regulations requiring reductions in the amount of oxides of nitrogen (NOx) and carbon monoxide (CO). Lower combustion emissions can often be attributed to a more efficient combustion process, with specific regard to fuel injector location and mixing effectiveness.
Early combustion systems utilized diffusion type nozzles, where fuel is mixed with air external to the fuel nozzle by diffusion, proximate the flame zone. Diffusion type nozzles have been known to produce high emissions due to the fact that the fuel and air burn stoichiometrically at high temperature to maintain adequate combustor stability and low combustion dynamics.
An enhancement in combustion technology is the utilization of premixing, such that the fuel and air mix prior to combustion to form a homogeneous mixture that burns at a lower temperature than a diffusion type flame and produces lower NOx emissions. Premixing fuel and air together before combustion allows for the fuel and air to form a more homogeneous mixture, which for a given combustor exit temperature will burn at lower peak temperatures, resulting in lower emissions. Example of such a gas turbine flamesheet combustion system with reduced emissions and improved flame stability at multiple load conditions is disclosed in US patent application US2004/0211186A1
While the combustors of the prior art have improved emissions levels and ability to operate at reduced load settings, thermoacoustics of the flamesheet combustors could still lead to instability modes (such as pulsation), which could restrict the operation window. Additionally, aerodynamics of the burner allows occasional flame attachment in the mixing zone under certain circumstances, causing flashback and overheating risk. Furthermore, current fuel staging strategies could cause asymmetrical heat load on the combustor liner, which could lead to creep problems.
In addition, measure which help against pulsation, as for example the staging of 1/3-2/3 groups in the main fuel supply can lead to asymmetrical liner heat loading, as well as to non-uniformities in the combustor exit temperature profile.
What is intended is a system that can provide further flame stability while also reducing thermoacoustic instabilities which can enlarge the operation window available of the current combustor designs. The embodiments described below are intended to widen the operation window beyond the currently available range, without sacrificing the low emission values.
SUMMARY OF THE INVENTIONIt is one object of the present invention to provide a combustor with further improved stability and improved thermoacoustics characteristics.
The above and other objects of the invention are achieved by a gas turbine combustor comprising a flow sleeve, a combustion liner located at least partially within the flow sleeve thereby creating a main passage between the flow sleeve and the combustor liner, and a dome located forward of the flow sleeve and encompassing at least a part of the combustion liner, the dome having a substantially rounded head end thereby forming a turning passage between the liner and the head end, and a swirler wall aligned along a centerline of the combustor, the swirler wall projecting into a space delimited by the liner, wherein the swirler wall and the rounded head end are connected, and wherein the connection forms an annular end face.
According to one embodiment of the present invention, the combustor further comprises a center body positioned along the centerline and extending into the space delimited by the swirler wall, thereby forming a pilot passage between the swirler wall and the center body.
According to yet another embodiment of the present invention, width of the pilot channel is substantially constant along the length of the pilot channel.
According to another embodiment of the present invention, an area of the annular end face is 1.5 times to 5 times larger than an area of a cross section of the pilot passage.
According to yet another embodiment of the present invention, a fuel lance is arranged in the center body.
According to another embodiment of the present invention, the combustor further comprises a substantially cylindrical extension extending from a radially inner end of the rounded head end or the end face into the liner, wherein the extension is aligned with the centerline of the combustor. According to yet another embodiment of the present invention, the extension has substantially constant radius along the centerline of the liner, and/or the thickness of the extension is substantially equal to the thickness of the rounded head end.
According to another embodiment of the present invention, a recess delimited by the central body, the annular end face and the rounded head end comprises a Helmholtz damper or/and means for pilot oil injection.
According to yet another embodiment of the present invention, the combustion liner comprises a ring shaped rounded lip section and a curved middle section adapted to create a flame stabilization zone during operation. According to another embodiment of the present invention the lip section comprises a Helmholtz damper and/or liquid fuel injection means.
According to another embodiment of the present invention, the pilot passage comprises a pilot swirler in fluid communication with at least one pilot fuel injector, and the pilot swirler is an axial swirler or a radial swirler. According to another embodiment of the present invention, the main passage or the turning passage comprises a main swirler in a fluid communication with at least one main fuel injector, and wherein the main swirler is an axial swirler or a radial swirler.
According to another embodiment of the present invention, the swirler wall is a part of a conical burner (e.g. EV burner or AEV burner).
The present application also provides for a gas turbine comprising the combustor described above.
In addition, the present application also provides for a method for operating the gas turbine combustor. The method comprising: supplying a first stream of fuel into the pilot channel or conical burner (e.g. EV burner or AEV burner) to mix with the first flow of air, and feeding the resulting first mixture into the combustion zone for providing pilot flame; supplying a second flow of air into the main passage; supplying a second stream of fuel into the main passage or turning passage to mix with the second flow of air, and feeding the resulting second mixture into the combustion zone for providing a main flame.
Additional advantages and features of the present invention will be set forth in part in a description which follows, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned from practice of the invention. The instant invention will now be described with particular reference to the accompanying drawings.
Preferred embodiments of the invention are described in the following with reference to the drawings, which are for the purpose of illustrating the present preferred embodiments of the invention and not for the purpose of limiting the same. In the drawings,
An example of a premixing flamesheet combustor 100 for a gas turbine of the prior art is shown in
In one embodiment according to the invention, the combustor 200 further comprises a center body 220 positioned along the centerline 216 and extending into the space delimited by the swirler wall 214. The swirler wall 214 and the center body 220 form a pilot passage 222. The center body comprises a front surface 226 which can have different shapes, depending on the combustor design, such as bluff body shape. The width of the pilot channel 222 can vary, and preferably is substantially constant along the length of the pilot channel 222. The center body 220 could also comprise a fuel lance 608 (shown in
The combustor 200 according to the invention in one embodiment can comprise main fuel supply 234, pilot fuel supply 230, main swirler with injectors 232 and pilot swirler with injectors 228 to create a pilot flame and a main flame during an operation of the combustor.
The embodiment comprising the ring shaped rounded lip section 420 and the curved middle section 430 is adapted to create an additional outer main flame stabilization zone 510 during operation as shown in
The combustor 200 according to the invention could comprise a conical burner 702,704 device instead of the center body 220. Examples of these embodiments are shown in
It should be apparent that the foregoing relates only to the preferred embodiments of the present application and that 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.
LIST OF DESIGNATIONS
- 1,2 Part cone bodies
- 3 Nozzle
- 5 Conical column
- 6 Backflow zone
- 14 Interior of a burner
- 15 Rotating stream
- 100 Combustor
- 102 Pilot nozzle
- 104 Radial inflow mixer
- 108 Main stage mixer
- 110 Divider
- 120 Flame front
- 200 Combustor
- 202 Flow sleeve
- 204 Combustion liner
- 206 Main passage
- 208 Dome
- 210 Head end
- 212 Turning passage
- 214 Swirler wall
- 216 Combustor centerline
- 218 End face
- 220 Center body
- 222 Pilot passage
- 226 Center body front surface
- 228 Pilot swirler with injectors
- 230 Pilot fuel supply
- 232 Main swirler with injectors
- 234 Main fuel supply
- 240 Extension
- 242 Recess
- 250 Combustion zone
- 260 Main flame
- 262 Pilot flame
- 420 Lip section
- 430 Curved middle section
- 440 Cooling holes
- 510 Main flame stabilization zone
- 520 Outer pilot stabilization zone
- 530 Central pilot stabilization zone
- 602 Helmholtz damper
- 604 Pilot oil injection
- 606 Oil injection
- 608 Fuel lance
- 610 Helmholtz damper
- 612 Helmholtz damper
- 614 Fuel injector
- 618 Pilot swirler
- 620 Main swirler
- 622 Fuel injector
- 702 EV burner
- 704 AEV burner
- 802 Mixing section
- 804 Tube
Claims
1. A gas turbine combustor comprising:
- a flow sleeve;
- a combustion liner located at least partially within the flow sleeve thereby creating a main passage between the flow sleeve and the combustor liner;
- a dome located forward of the flow sleeve and encompassing at least a part of the combustion liner, the dome having a substantially rounded head end thereby forming a turning passage between the liner and the head end; and
- a swirler wall aligned along a centerline of the combustor, the swirler wall projecting into a space delimited by the liner,
- wherein the swirler wall and the rounded head end are connected, wherein the connection forms an annular end face.
2. The combustor of claim 1 further comprising a center body positioned along the centerline and extending into the space delimited by the swirler wall, thereby forming a pilot passage between the swirler wall and the center body.
3. The combustor of claim 1 wherein a width of the pilot channel is substantially constant along the length of the pilot channel.
4. The combustor of claim 1, wherein an area of the annular end face is 1.5 times to 5 times larger than an area of a cross section of the pilot passage.
5. The combustor of claim 1, wherein a fuel lance is arranged in the center body.
6. The combustor of claim 1 further comprising a substantially cylindrical extension extending from a radially inner end of the rounded head end or the end face into the liner, wherein the extension is aligned with the centerline of the combustor.
7. The combustor of claim 8, wherein the extension has substantially constant radius along the centerline of the liner, and/or wherein the thickness of the extension is substantially equal to the thickness of the rounded head end.
8. The combustor of claim 1, wherein a recess delimited by the central body, the annular end face and the rounded head end comprises a Helmholtz damper or/and a means for pilot oil injection.
9. The combustor of claim 1, wherein the combustion liner comprises a ring shaped rounded lip section and a curved middle section adapted to create a flame stabilization zone during operation.
10. The combustor of claim 8, wherein the lip section comprises a Helmholtz damper and/or liquid fuel injection means.
11. The combustor of claim 1, wherein the pilot passage comprises a pilot swirler in fluid communication with at least one pilot fuel injector, and wherein the pilot swirler is an axial swirler or a radial swirler.
12. The combustor of claim 1, wherein the main passage or the turning passage comprises a main swirler in a fluid communication with at least one main fuel injector, and wherein the main swirler is an axial swirler or a radial swirler.
13. The combustor of claim 1, wherein the swirler wall is a part of a conical burner.
14. A gas turbine comprising the combustor according to claim 1.
15. A method for operating the gas turbine combustor according to claim 1, the method comprising: supplying a first stream of fuel into the pilot channel or the conical burner, and feeding the resulting first mixture into the combustion zone for providing pilot flame;
- supplying a second flow of air into the main passage; supplying a second stream of fuel into the main passage or turning passage to mix with the second flow of air, and feeding the resulting second mixture into the combustion zone for providing a main flame.
Type: Application
Filed: Nov 24, 2015
Publication Date: May 26, 2016
Applicant: General Electric Technology GmbH (Baden)
Inventors: Ennio PASQUALOTTO (Winterthur), Douglas Anthony PENNELL (Windisch), Michael DÜSING (Rheinfelden)
Application Number: 14/950,601