Extinction and flame bifurcations of stretched dimethyl-ether premixed flames

Yuan Xue, Yiguang Ju

Research output: Contribution to conferencePaperpeer-review

Abstract

Extinction limits and flame bifurcation of lean premixed dimethyl ether-air flames were studied numerically using the counterflow flame with a reduced chemistry. A method based on the reaction front was presented to predict the Markstein length. The predicted positive Markstein length agreed well with the experimental data. The flow stretch significantly reduced the flame speed and narrowed the flammability limit of the stretched dimethyl ether-air flame. The combined effect of radiation and flow stretch resulted in a new flame bifurcation and multiple flame regimes. At an equivalence ratio slightly higher than the flammability limit of the planar flame, the distant flame regime appears at low stretch rates. With an increase of the equivalence ratio, in addition to the distant flame, a weak flame isola emerged at moderate stretch rates. With a further increase of the equivalence ratio, the distant flame and the weak flame branches merged together, resulting in the splitting of the weak flame branch into two weak flame branches, one at low stretch and the other at high stretch. Flame stability analysis demonstrated that the high stretch weak flame is also stable. A K-shaped flammability limit diagram showing various flame regimes and their extinction limits were obtained.

Original languageEnglish (US)
Number of pages1
StatePublished - Jan 1 2004
Event30th International Symposium on Combustion, Abstracts of Symposium Papers - Chicago, IL, United States
Duration: Jul 25 2004Jul 30 2004

Other

Other30th International Symposium on Combustion, Abstracts of Symposium Papers
CountryUnited States
CityChicago, IL
Period7/25/047/30/04

All Science Journal Classification (ASJC) codes

  • Engineering(all)

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