Normal and microgravity experiment of oscillating lifted flames in coflow

S. H. Won, J. Kim, M. K. Shin, S. H. Chung, O. Fujita, T. Mori, J. H. Choi, K. Ito

Research output: Contribution to journalConference articlepeer-review

45 Scopus citations

Abstract

Characteristics of oscillating lifted flames in coflow have been investigated experimentally with highly diluted propane in both normal gravities and microgravities to elucidate the oscillation mechanism. In normal gravity, oscillating lifted flames with the frequency of 2-5 Hz were observed in a certain range of fuel mole fraction and jet velocity for the jet Reynolds number smaller than 100. The oscillation frequency in terms of the Strouhal number, defined in terms of the stoichiometric laminar burning velocity, correlated well with jet velocity. This demonstrated the importance of the propagation characteristics of tribrachial flames at the base of lifted flames in the flame oscillation. Microgravity experiments have been conducted after the oscillating lifted flames were stabilized in normal gravity. During the change in gravitational acceleration, the flames rapidly stabilized as nozzle attached flames and became stationary. This behavior confirmed that the lifted flame oscillation in normal gravity is due to the buoyancy driven instability. Numerical simulation has also been performed accounting the change in gravitational acceleration. The results successfully predicted the transition behavior from oscillating lifted flame in normal gravity to stationary nozzle attached flame in microgravity and the variation of flame shapes during the transition.

Original languageEnglish (US)
Pages (from-to)37-44
Number of pages8
JournalProceedings of the Combustion Institute
Volume29
Issue number1
DOIs
StatePublished - Jan 1 2002
Event30th International Symposium on Combustion - Chicago, IL, United States
Duration: Jul 25 2004Jul 30 2004

ASJC Scopus subject areas

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

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