Role of chain mechanism in ignition and combustion of hydrogen-oxygen mixtures near the third explosion limit

In contrast to the commonly accepted opinion, the ignition and combustion of hydrogen and oxygen (air) mixtures near the third ignition limit under atmospheric pressure are shown to occur via the branched-chain mechanism, which largely determines the essential features of the process under these conditions and under lower pressures. The joint effect of branching and self-heating on the kinetics is discussed. The competition between chain branching and chain termination steps along with self-heating governs the phenomenology of many other combustion processes over a wide range of pressures and temperatures.