Effect of hydrogen additives on the kinetics of formation and destruction of acetylene during the ignition and combustion of methane-oxygen mixtures

The kinetics of formation and destruction of acetylene during the self-ignition of methane-oxygen mixtures with and without hydrogen additives in a closed volume have been studied by numerical analysis. The time dependence of the acetylene concentration exhibits a sharp peak at a maximum concentration and slightly descends with increasing initial temperature and hydrogen concentration in the studied range. Ignition delays and the time of concentration decay after maximum significantly decrease with increasing initial temperature, hydrogen concentration, and pressure. It has been speculated that the experimentally observed decrease in the yield and particle size of soot owing to hydrogen additives to a hydrocarbon-oxygen mixture is attributed to a strong decrease in the lifetime of significant acetylene concentrations in the reaction zone which is caused by these additives.