Further examinations on extinction and bifurcations of radiative CH 4/air and C3H8/air premixed flames

Yiguang Ju, Goro Masuya, Fengshan Liu, Hongsheng Guo, Kaoru Maruta, Takashi Niioka

Research output: Contribution to journalConference article

11 Scopus citations

Abstract

The extinction and flame bifurcations of radiative CH4/air and C3H8/air free propagating flames and counterflow flames are investigated numerically with detailed chemistry as well as the optically thin and spectral emission-absorption statistical narrow band models. For counterflow CH4/air flame, a G-shaped extinction curve is obtained. It is shown that flame bifurcations and extension of the flammability limit due to the interaction of radiation and stretch at subunity Lewis number exist regardless the radiation model used. Furthermore, it is shown that even for small-scale flame, radiation reabsorption greatly extends the flammable regions of the weak flame (WF) and the near-stagnation flame (NSF). For counterflow C3H8/air flame, a K-shaped extinction curve is obtained. It is concluded that multiple flame bifurcations are the physically intrinsic phenomena of the practical stretched flames. It is shown that the extrapolation of the stretched extinction limit to zero stretch rate is possible only when the extinction curve is K-shaped. Transition from the G-shaped extinction curve to the K-shaped one, as a result of the competition between radiation heat loss and the Lewis number effect, is examined by replacing the nitrogen gas in CH 4/air mixture with helium. The critical Lewis number for the transition of the extinction curve is obtained. Results of the present study show good agreement with theory and experiment.

Original languageEnglish (US)
Pages (from-to)2551-2557
Number of pages7
JournalSymposium (International) on Combustion
Volume27
Issue number2
DOIs
StatePublished - 1998
Event27th International Symposium on Combustion - Boulder, CO, United States
Duration: Aug 2 1998Aug 7 1998

All Science Journal Classification (ASJC) codes

  • Chemical Engineering(all)
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Mechanical Engineering
  • Physical and Theoretical Chemistry
  • Fluid Flow and Transfer Processes

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