An integral analysis of the structure and propagation of stretched premixed flames

The structure and propagation of stretched premixed flames with preferential diffusion are analyzed using an approximate integral approach which yields algebraic relations for the characteristic scales, overall conservation requirements, and balances and continuity between the various scalar properties and their transport rates. Specific flame configurations studied include the one-dimensional steadily propagating planar flame, the steady curved flame in nonuniform flow, and the outwardly/inwardly propagating spherical flame. Linearized results agree with those obtained from asymptotic analysis assuming small stretch. The present work yields enhanced insight into the dominant and coupled physical processes governing these complex flame phenomena, and demonstrates the utility of the integral analysis in theoretical combustion studies.