Abstract
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 language | English (US) |
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Pages | 42 |
Number of pages | 1 |
State | Published - 2002 |
Externally published | Yes |
Event | 29th International Symposium on Combustion - Sapporo, Japan Duration: Jul 21 2002 → Jul 26 2002 |
Other
Other | 29th International Symposium on Combustion |
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Country/Territory | Japan |
City | Sapporo |
Period | 07/21/02 → 07/26/02 |
ASJC Scopus subject areas
- General Engineering