Abstract
We numerically examine in this study the effect of heat loss on triple flame propagation in porous channels. Unlike previous studies that were based on a counterflow configuration, we consider a porous channel in which a nonstrained two-dimensional mixing layer is created as a result of the constant concentrations of the reactants-fuel and oxidizersupplied at the walls. The problem is formulated mathematically within the framework of a thermodiffusive model and a single-step chemistry along with a volumetric heat loss, and then solved numerically using finite elements. The results have identified the effect of two main nondimensional parameters on flame propagation, namely the heat loss kappa and the flame-front thickness". Such parameters are found to be crucial for the existence of multiple solutions and hysteresis phenomena characterizing distinct combustion regimes. The number and the domain of existence of multiple solutions are identified in the kappa-epsilon plane. The overall impact of heat loss on triple flames is to a large extent found to be qualitatively similar to that reported for flame edges propagating in counterflow. The study has also described the transition of the flame structure across the combustion regimes, between triple flames, edge flames, and flame tubes.