Dynamic flammability limits of methane-air premixed flames with mixture composition fluctuations

Ramanan Sankaran, Hong G. Im

Research output: Contribution to conferencePaperpeer-review


Unsteady premixed methane-air flames subjected to time-varying composition fluctuations were studied computationally as a fundamental study in the application to DISI engines or gas turbines where mixture stratification and partial quenching is of serious concern. The code, OPUS, employed an unsteady opposed-flow combustion configuration including detailed chemical kinetics, transport, and radiation models, using an adaptive time integration method for a stiff system of differential-algebraic equations with a high index. The concept of the dynamic flammability limit, defined as the minimum equivalence ratio above which the unsteady flame can sustain combustion was studied. For the weak and strong strain rate cases, the dynamic flammability limit depended on the mean and frequency of the composition fluctuation. The flammability limit of an unsteady premixed flame was further extended to the leaner condition as the frequency or mean equivalence ratio fluctuation increases. The instantaneous branching-termination balance at the reaction zone primarily determined the dynamic flammability limit. Original is an abstract.

Original languageEnglish (US)
Number of pages1
StatePublished - 2002
Externally publishedYes
Event29th International Symposium on Combustion - Sapporo, Japan
Duration: Jul 21 2002Jul 26 2002


Other29th International Symposium on Combustion

ASJC Scopus subject areas

  • General Engineering


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