Title:
Acoustic Characterization of Flame Blowout Phenomenon

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dc.contributor.advisor Lieuwen, Timothy C.
dc.contributor.author Nair, Suraj en_US
dc.contributor.committeeMember Zinn, Ben T.
dc.contributor.committeeMember Jagoda, Jechiel I.
dc.contributor.committeeMember Seitzman, Jerry M.
dc.contributor.committeeMember Soteriou, Marios
dc.contributor.department Aerospace Engineering en_US
dc.date.accessioned 2006-06-09T17:39:58Z
dc.date.available 2006-06-09T17:39:58Z
dc.date.issued 2006-02-10 en_US
dc.description.abstract Combustor blowout is a very serious concern in modern land-based and aircraft engine combustors. The ability to sense blowout precursors can provide significant payoffs in engine reliability and life. The objective of this work is to characterize the blowout phenomenon and develop a sensing methodology which can detect and assess the proximity of a combustor to blowout by monitoring its acoustic signature, thus providing early warning before the actual blowout of the combustor. The first part of the work examines the blowout phenomenon in a piloted jet burner. As blowout was approached, the flame detached from one side of the burner and showed increased flame tip fluctuations, resulting in an increase in low frequency acoustics. Work was then focused on swirling combustion systems. Close to blowout, localized extinction/re-ignition events were observed, which manifested as bursts in the acoustic signal. These events increased in number and duration as the combustor approached blowout, resulting an increase in low frequency acoustics. A variety of spectral, wavelet and thresholding based approaches were developed to detect precursors to blowout. The third part of the study focused on a bluff body burner. It characterized the underlying flame dynamics near blowout in greater detail and related it to the observed acoustic emissions. Vorticity was found to play a significant role in the flame dynamics. The flame passed through two distinct stages prior to blowout. The first was associated with momentary strain levels that exceed the flames extinction strain rate, leading to flame holes. The second was due to large scale alteration of the fluid dynamics in the bluff body wake, leading to violent flapping of the flame front and even larger straining of the flame. This led to low frequency acoustic oscillations, of the order of von Karman vortex shedding. This manifested as an abrupt increase in combustion noise spectra at 40-100 Hz very close to blowout. Finally, work was also done to improve the robustness of lean blowout detection by developing integration techniques that combined data from acoustic and optical sensors. en_US
dc.description.degree Ph.D. en_US
dc.format.extent 3224956 bytes
dc.format.mimetype application/pdf
dc.identifier.uri http://hdl.handle.net/1853/10413
dc.language.iso en_US
dc.publisher Georgia Institute of Technology en_US
dc.subject Acoustics en_US
dc.subject Precursors
dc.subject Extinction
dc.subject Bluff body
dc.subject Flame dynamics
dc.subject Blowout
dc.subject.lcsh Combustion engineering en_US
dc.subject.lcsh Flame en_US
dc.subject.lcsh Aircraft gas-turbines Combustion en_US
dc.subject.lcsh Combustion en_US
dc.title Acoustic Characterization of Flame Blowout Phenomenon en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Lieuwen, Timothy C.
local.contributor.corporatename College of Engineering
local.contributor.corporatename Daniel Guggenheim School of Aerospace Engineering
local.relation.ispartofseries Doctor of Philosophy with a Major in Aerospace Engineering
relation.isAdvisorOfPublication b612098b-d0e6-4ea2-a8d5-92d6d02fe6c4
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
relation.isOrgUnitOfPublication a348b767-ea7e-4789-af1f-1f1d5925fb65
relation.isSeriesOfPublication f6a932db-1cde-43b5-bcab-bf573da55ed6
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