Flow structures in a lean-premixed swirl-stabilized combustor with microjet air injection

Handle URI:
http://hdl.handle.net/10754/598342
Title:
Flow structures in a lean-premixed swirl-stabilized combustor with microjet air injection
Authors:
LaBry, Zachary A.; Shanbhogue, Santosh J.; Speth, Raymond L.; Ghoniem, Ahmed F.
Abstract:
The major challenge facing the development of low-emission combustors is combustion instability. By lowering flame temperatures, lean-premixed combustion has the potential to nearly eliminate emissions of thermally generated nitric oxides, but the chamber acoustics and heat release rate are highly susceptible to coupling in ways that lead to sustained, high-amplitude pressure oscillations, known as combustion instability. At different operating conditions, different modes of instability are observed, corresponding to particular flame shapes and resonant acoustic modes. Here we show that in a swirl-stabilized combustor, these instability modes also correspond to particular interactions between the flame and the inner recirculation zone. Two stable and two unstable modes are examined. At lean equivalence ratios, a stable conical flame anchors on the upstream edge of the inner recirculation zone and extends several diameters downstream along the wall. At higher equivalence ratios, with the injection of counter-swirling microjet air flow, another stable flame is observed. This flame is anchored along the upstream edge of a stronger recirculation zone, extending less than one diameter downstream along the wall. Without the microjets, a stationary instability coupled to the 1/4 wave mode of the combustor shows weak velocity oscillations and a stable configuration of the inner and outer recirculation zones. Another instability, coupled to the 3/4 wave mode of the combustor, exhibits periodic vortex breakdown in which the core flow alternates between a columnar mode and a vortex breakdown mode. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.
Citation:
LaBry ZA, Shanbhogue SJ, Speth RL, Ghoniem AF (2011) Flow structures in a lean-premixed swirl-stabilized combustor with microjet air injection. Proceedings of the Combustion Institute 33: 1575–1581. Available: http://dx.doi.org/10.1016/j.proci.2010.06.092.
Publisher:
Elsevier BV
Journal:
Proceedings of the Combustion Institute
KAUST Grant Number:
KUS-110-010-01
Issue Date:
2011
DOI:
10.1016/j.proci.2010.06.092
Type:
Article
ISSN:
1540-7489
Sponsors:
This research was funded under Grant KUS-110-010-01 from the King Abdullah University of Science and Technology and UTSR/DOE Grant No. SUB 05-21-SR121.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorLaBry, Zachary A.en
dc.contributor.authorShanbhogue, Santosh J.en
dc.contributor.authorSpeth, Raymond L.en
dc.contributor.authorGhoniem, Ahmed F.en
dc.date.accessioned2016-02-25T13:19:02Zen
dc.date.available2016-02-25T13:19:02Zen
dc.date.issued2011en
dc.identifier.citationLaBry ZA, Shanbhogue SJ, Speth RL, Ghoniem AF (2011) Flow structures in a lean-premixed swirl-stabilized combustor with microjet air injection. Proceedings of the Combustion Institute 33: 1575–1581. Available: http://dx.doi.org/10.1016/j.proci.2010.06.092.en
dc.identifier.issn1540-7489en
dc.identifier.doi10.1016/j.proci.2010.06.092en
dc.identifier.urihttp://hdl.handle.net/10754/598342en
dc.description.abstractThe major challenge facing the development of low-emission combustors is combustion instability. By lowering flame temperatures, lean-premixed combustion has the potential to nearly eliminate emissions of thermally generated nitric oxides, but the chamber acoustics and heat release rate are highly susceptible to coupling in ways that lead to sustained, high-amplitude pressure oscillations, known as combustion instability. At different operating conditions, different modes of instability are observed, corresponding to particular flame shapes and resonant acoustic modes. Here we show that in a swirl-stabilized combustor, these instability modes also correspond to particular interactions between the flame and the inner recirculation zone. Two stable and two unstable modes are examined. At lean equivalence ratios, a stable conical flame anchors on the upstream edge of the inner recirculation zone and extends several diameters downstream along the wall. At higher equivalence ratios, with the injection of counter-swirling microjet air flow, another stable flame is observed. This flame is anchored along the upstream edge of a stronger recirculation zone, extending less than one diameter downstream along the wall. Without the microjets, a stationary instability coupled to the 1/4 wave mode of the combustor shows weak velocity oscillations and a stable configuration of the inner and outer recirculation zones. Another instability, coupled to the 3/4 wave mode of the combustor, exhibits periodic vortex breakdown in which the core flow alternates between a columnar mode and a vortex breakdown mode. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.en
dc.description.sponsorshipThis research was funded under Grant KUS-110-010-01 from the King Abdullah University of Science and Technology and UTSR/DOE Grant No. SUB 05-21-SR121.en
dc.publisherElsevier BVen
dc.subjectCombustion instabilityen
dc.subjectCounter swirlen
dc.subjectLean-premixed combustionen
dc.subjectParticle image velocimetryen
dc.subjectVortex breakdownen
dc.titleFlow structures in a lean-premixed swirl-stabilized combustor with microjet air injectionen
dc.typeArticleen
dc.identifier.journalProceedings of the Combustion Instituteen
dc.contributor.institutionMassachusetts Institute of Technology, Cambridge, United Statesen
kaust.grant.numberKUS-110-010-01en
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