Shock-Tube Study of the Hydrogen—Oxygen Reaction. II. Role of Exchange Initiation

Abstract

An extended analytical solution to the rate equations for the branching-chain reactions of the H2–O2 reaction under shock-tube conditions is presented. Together with an experimental determination of the detection threshold for OH of the Bi (3067) line-absorption method used in earlier experiments, this solution allows quantitative comparison of calculated and experimental ignition delays. It is shown that calculation and experiment can be brought into agreement with slight modification of chain-reaction rate coefficients deduced from the results of other studies of the H2–O2 reaction. The essential role of the rate of chain initiation by a path other than diatom dissociation in determining the ignition delays is brought to light. Rate-coefficient expressions for the chain reactions are suggested and supported.