The Extinction of Methane/Methyl Chloride Nonpremixed Flames

The extinction of nonpremixed flames burning mixtures of methane and methyl chloride, air, and nitrogen is studied in a counterflowing flame. The flowrates entering the counterflow are varied so as to measure the critical strain rate at extinction. Increasing amounts of methyl chloride, as expected, are determined to lower the value of the critical strain rate at extinction. The experiments are conducted at conditions corresponding to several fixed values of the stoichiometric mixture fractions and compared with a previously developed analysis in order to determine forced global kinetic parameters characterizing these cases. The kinetic parameters are found to be useful engineering quantities that enumerate an incinerability ranking. It is determined from the experimental results that small amounts of added methyl chloride have a significant inhibitory effect on methane-air flames, but that larger addition of methyl chloride does not yield a proportional inhibitory effect.