An asymptotic analysis of branched-chain ignition of cold combustible gas by hot inert gas

An asymptotic analysis of large activation energy with regard to ignition or flame initiation of a cold combustible gas stream coming into contact with a hot inert gas stream is presented. Two-step reaction kinetics, that is, a first-order chain-branching reaction and a second-order chain-termination reaction, responsible for ignition is adopted, and the dependence of ignition time (or flame attachment distance) on the second-order recombination reaction is examined. Equations for ignition delay are given by means of elementary functions, which show that ignition time increases with an increase in recombination reaction rate.