Experimental study of spinning combustion in a mesoscale divergent channel

Bo Xu, Yiguang Ju

Research output: Contribution to journalConference articlepeer-review

68 Scopus citations

Abstract

Quasi-steady and unsteady propagations of methane and propane-air premixed flames in a mesoscale divergent channel were investigated experimentally and theoretically. The emphasis was the impact of variable cross-section area and the flame-wall coupling on the flame transition between different regimes and the onset of flame instability. Experimentally, for the first time, spinning flames were observed in mesoscale combustion for both lean and rich methane and propane-air mixtures in a broad range of equivalence ratios. The spinning flames rotated in either clockwise or counterclockwise direction with equal probability. The results showed that for a fixed equivalence ratio, there was a critical flow rate, above which flame starts to spin. The spin frequency was approximately proportional to the flame speed. It was also found that the spinning flame only occurred after the transition from fast flame regime to slow flame regime. The flame propagation speed and the effective Lewis number were obtained analytically. Experimental observation and theoretical analysis suggested that regardless of the magnitude of mixture Lewis numbers, the flame-wall coupling will significantly increase the effective Lewis number and lead to a new mechanism to promote the thermal diffusion instability.

Original languageEnglish (US)
Pages (from-to)3285-3292
Number of pages8
JournalProceedings of the Combustion Institute
Volume31 II
DOIs
StatePublished - 2007
Event31st International Symposium on Combustion - Heidelberg, Germany
Duration: Aug 5 2006Aug 11 2006

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Mechanical Engineering
  • Physical and Theoretical Chemistry

Keywords

  • Flame instability
  • Mesoscale
  • Microscale
  • Premixed flame
  • Spin flame

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