Laminar flame propagation with volumetric heat loss and chain branching-termination reactions

The steady propagation of the planar laminar premixed flame in the doubly-infinite domain, with chain branching-termination reactions and weak volumetric heat loss, is studied using activation energy asymptotics. Two flame propagation regimes are identified and analyzed: a fast recombination regime in which the recombination reaction occurs in a steady-state manner with the high-activation-energy branching reaction in an overall reaction region which is much thinner than that of diffusion, and an intermediate recombination regime in which the recombination region is much thicker than the branching region but much thinner than the diffusion region. The analysis yields the characteristic dual solution, extinction turning point flame response, and shows that the flame propagation speed is reduced to e ^{-1 2} of the adiabatic value for both reaction mechanisms. The generality of this limit flame speed is noted.