Oxidation of hydrogen-oxygen mixtures under isothermal conditions near self-ignition limits

A set of chemical kinetic equations describing the change in the concentration of active species in an isothermal hydrogen-oxygen gas mixture at 700-900 K is considered. Four types of active species are analyzed: hydrogen and oxygen atoms and OH and HO2 radicals. For these active species, the conditions of stability of a 2 : 1 [H-2] : [O-2] reaction mixture to small perturbations of the initial composition are found. Two criteria for dividing the set of parameters of the reaction mixture into those corresponding to stable and unstable states are presented. The boundary between these states is the boundary of self-ignition of the reaction mixture. The results of numerical calculations are given, which show a noticeable displacement of the self-ignition boundary in the presence of HO2 radicals at a concentration of 3 x 10(11) cm(-3) in the mixture.