Mode Selection in Flame-Vortex driven Combustion Instabilities

Handle URI:
http://hdl.handle.net/10754/598847
Title:
Mode Selection in Flame-Vortex driven Combustion Instabilities
Authors:
Speth, Ray; Hong, Seung Hyuck; Shanbogue, Santosh; Ghoniem, Ahmed
Abstract:
In this paper, we investigate flame-vortex interaction in a lean premixed, laboratory scale, backward-facing step combustor. Two series of tests were conducted, using propane/hydrogen mixtures and carbon monoxide/hydrogen mixtures as fuels, respectively. Pressure measurements and high speed particle imaging velocimetry (PIV) were employed to generate pressure response curves as well as the images of the velocity field and the flame brush. We demonstrate that the step combustor exhibits several operating modes depending on the inlet conditions and fuel composition, characterized by the amplitude and frequency of pressure oscillations along with distinct dynamic flame shapes. We propose a model in which the combustor's selection of the acoustic mode is governed by a combustion-related time delay inversely proportional to the flame speed. Our model predicts the transition between distinct operating modes. We introduce non-dimensional parameters characterizing the flame speed and stretch rate, and develop a relationship between these quantities at the operating conditions corresponding to each mode transition. Based on this relationship, we show that numerically-calculated density-weighted strained flame speed can be used to collapse the combustion dynamics data over the full range of conditions (inlet temperature, fuel composition, and equivalence ratio). Finally, we validate our strain flame based model by measuring the strain rate using the flame image and the velocity field from the PIV measurement. Our results show that the measured strain rates lie in the same range as the critical values at the transitions among distinct modes as those predicted by our model.
Citation:
Speth R, Hong SH, Shanbogue S, Ghoniem A (2011) Mode Selection in Flame-Vortex driven Combustion Instabilities. 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. Available: http://dx.doi.org/10.2514/6.2011-236.
Publisher:
American Institute of Aeronautics and Astronautics (AIAA)
Journal:
49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition
KAUST Grant Number:
KUS-110-010-01
Issue Date:
4-Jan-2011
DOI:
10.2514/6.2011-236
Type:
Conference Paper
Sponsors:
The authors would like to acknowledge the King Abdullah University of Science and Technology for their support of this research. This work was funded by the KAUST grant, number KUS-110-010-01.
Appears in Collections:
Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorSpeth, Rayen
dc.contributor.authorHong, Seung Hyucken
dc.contributor.authorShanbogue, Santoshen
dc.contributor.authorGhoniem, Ahmeden
dc.date.accessioned2016-02-25T13:42:21Zen
dc.date.available2016-02-25T13:42:21Zen
dc.date.issued2011-01-04en
dc.identifier.citationSpeth R, Hong SH, Shanbogue S, Ghoniem A (2011) Mode Selection in Flame-Vortex driven Combustion Instabilities. 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. Available: http://dx.doi.org/10.2514/6.2011-236.en
dc.identifier.doi10.2514/6.2011-236en
dc.identifier.urihttp://hdl.handle.net/10754/598847en
dc.description.abstractIn this paper, we investigate flame-vortex interaction in a lean premixed, laboratory scale, backward-facing step combustor. Two series of tests were conducted, using propane/hydrogen mixtures and carbon monoxide/hydrogen mixtures as fuels, respectively. Pressure measurements and high speed particle imaging velocimetry (PIV) were employed to generate pressure response curves as well as the images of the velocity field and the flame brush. We demonstrate that the step combustor exhibits several operating modes depending on the inlet conditions and fuel composition, characterized by the amplitude and frequency of pressure oscillations along with distinct dynamic flame shapes. We propose a model in which the combustor's selection of the acoustic mode is governed by a combustion-related time delay inversely proportional to the flame speed. Our model predicts the transition between distinct operating modes. We introduce non-dimensional parameters characterizing the flame speed and stretch rate, and develop a relationship between these quantities at the operating conditions corresponding to each mode transition. Based on this relationship, we show that numerically-calculated density-weighted strained flame speed can be used to collapse the combustion dynamics data over the full range of conditions (inlet temperature, fuel composition, and equivalence ratio). Finally, we validate our strain flame based model by measuring the strain rate using the flame image and the velocity field from the PIV measurement. Our results show that the measured strain rates lie in the same range as the critical values at the transitions among distinct modes as those predicted by our model.en
dc.description.sponsorshipThe authors would like to acknowledge the King Abdullah University of Science and Technology for their support of this research. This work was funded by the KAUST grant, number KUS-110-010-01.en
dc.publisherAmerican Institute of Aeronautics and Astronautics (AIAA)en
dc.titleMode Selection in Flame-Vortex driven Combustion Instabilitiesen
dc.typeConference Paperen
dc.identifier.journal49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Expositionen
dc.contributor.institutionMassachusetts Institute of Technologyen
kaust.grant.numberKUS-110-010-01en
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