Asymptotic Analysis of Two-Reactant Flames With Variable Properties and Stefan-Maxwell Transport

Abstract

Two-term expansions for burning velocity in activation-energy asymptotics are developed for four-species, two-reactant, steady, planar, adiabatic laminar flames with irreversible one-step chemistry. General Stefan-Maxwell transport is included with Soret and Dufour effects, pressure gradients, body forces and radiant transport neglected. The results lead to identification of effective Lewis numbers (combinations of Lewis numbers for different pairs of species) that affect the burning velocity, and by exhibiting influences of fully variable transport and thermodynamic properties they provide a basis for achieving improved accuracy in asymptotic analysis of flame propagation in two-reactant systems such as hydrogen-halogen mixtures. When suitably specialized to the more restrictive conditions considered in earlier work, the burning velocities obtained here agree with those derived previously