Quenching of Flame Propagation Through Endothermic Reaction

The propagation of a premixed laminar flame supported by an exothermic chemical reaction under adiabatic conditions but subject to inhibition through a parallel endothermic chemical process is considered. The temperature dependence of the reaction rates is assumed to have a generalised Arrhenius type form with an ignition temperature, below which there is no reaction. The heat loss through the endothermic reaction, represented by the dimensionless parameter , has a strong quenching effect on wave initiation and propagation. The temperature profile can have a front or a pulse structure depending on the relative value of the ignition temperatures and on the value of the parameters and , the latter represents the rate at which inhibitor is consumed relative to the consumption of fuel. The wave speed-cooling parameter () curves are determined for various values of the other parameters. These curves can have three different shapes: monotone decreasing, -shaped or S-shaped, with the possibility of having one, two or three different flame velocities for the same value of the cooling parameter .