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Lagrangian saddle point analysis in the flow-field of a bluff-body stabilized combustor
C.P. Premchand, N.B. George, M. Raghunathan, , R.I. Sujith, V. Nair
Published in American Society of Mechanical Engineers (ASME)
2019
Volume: 4B-2019
   
Abstract
Experiments are performed in a partially-premixed bluff-body stabilized turbulent combustor by varying the mean flow velocity. Simultaneous measurements obtained for unsteady pressure, velocity and heat release rate are used to investigate the dynamic regimes of intermittency (10.1 m/s) and thermoacoustic instability (12.3 m/s). Using wavelet analysis, we show that during intermittency, modulation of heat release rate occurring at the acoustic frequency fa by the heat release rate occurring at the hydrodynamic frequency fh results in epochs of heat release rate fluctuations where the heat release is phase locked with the acoustic pressure. We also show that the flame position during intermittency and thermoacoustic instability are essentially dictated by saddle point dynamics in the dump plane and the leading edge of the bluff-body. Copyright © 2019 ASME.
About the journal
JournalProceedings of the ASME Turbo Expo
PublisherAmerican Society of Mechanical Engineers (ASME)