Effect of heat-loss on flame-edges in a premixed counterflow

Abstract

We describe the combined influence of heat-loss and strain (characterized here by non-dimensional parameters κ and ε, respectively) on premixed flame-edges in a two-dimensional counterflow configuration. The problem is formulated as a thermo-diffusive model with a single Arrhenius reaction. In order to help classify the various flame-edge regimes, the non-adiabatic one-dimensional problem which characterizes the wings (far downstream) of the flame-edge is briefly revisited and its solutions are delimited in the κ–ε plane. An analytical description of the flame-edges is then presented in the weak-strain limit ε→0. This is complemented by a detailed numerical study. Several combustion regimes are found and their domains of existence are identified in the κ–ε plane. These include ignition fronts, extinction fronts, solutions with propagation speeds that depend non-monotonically on the strain-rate, propagating flame tubes and stationary flame tubes. Multiplicity of solutions and hysteresis phenomena, which are partly but not exclusively associated with the one-dimensional regimes, are also identified and discussed.