Ignition of Combustible Gases by Converging Shock Waves

Abstract

Hydrogen‐oxygen and hydrogen‐air mixtures were ignited by converging cylindrical shock waves using the apparatus devised by Perry and Kantrowitz [J. Appl. Phys. 22, 878–886 (1951)], and the minimum strength shock wave necessary for ignition was determined. The enthalpy increase in the wake of the shock wave within a cylinder of diameter equal to the quenching distance and of unit height was calculated and found to be comparable with the minimum spark ignition energy divided by the quenching distance. An analysis of the unsteady heat conduction problem lends support to the choice of the quenching distance as the significant dimension of the region over which heat addition is effective in causing ignition.