EXPERIMENTAL INVESTIGATION OF STRETCHED PREMIXED FLAMES BURNING MIXTURES OF METHANE AND METHYL-CHLORIDE IN AIR AND COMPARISON WITH NUMERICAL SIMULATIONS

Experimental measurements of the laminar burning velocities of flames burning methane/methyl chloride mixtures, and methyl chloride in air, are made in a counterflow burner. The flame speeds are observed to decrease with increasing chlorine loading, from 40 cm s-1 for a stoichiometric methane-air flame to 4.9 cm s-1 for a stoichiometric methyl chloride-air flame. Good agreement is found between flame speeds deduced from experiments and those predicted by numerical simulations at the periphery of the domain, i.e., for methane-air and methyl chloride-air flames. The agreement between experiments and calculations at intermediate regions, that is, for varying methane-methyl chloride-air mixtures is at best reasonable. Sources for the discrepancies in the kinetic mechanism are identified. The critical extinction stretch rate for flames burning methyl chloride in air is measured, as is the stretched flame speed close to extinction.