EXPLOSIVE MECHANISM OF THE H2-O2 REACTION NEAR THE SECOND IGNITION LIMIT,

An investigation of the H2-O2 explosion behind reflected shocks was performed under conditions of low temperature and high pressure. Simultaneous measurements of pressure, UV light transmission, and schlieren streak photographs of the shock reflection-reaction wave formation process were made. Pressure spikes, emission, and absorption maxima were observed at times which correspond to the initiation of the reaction wave. The delay to the initial UV absorption was between 70 and 90 percent of the reaction wave delay. Contrary to what has previously been reported, the pressure and temperature dependence of the delays to initial absorption and to the initiation of the reaction wave did not differ. The analysis used by Voevodski and Soloukhin for calculating reaction wave delays in undiluted H2-O2 mixtures gave good agreement with experiments in both Ar-diluted and undiluted mixtures. The apparent failure of the analysis at the lowest temperatures is attributed to limitations on shock tube test time. Author