Relation between cell size, induction zone length and critical initiation energy in oxyhydrogen detonations.

Abstract

Detonation cell size has been measured in a mixture of hydrogen with oxygen over wide ranges of equivalence ratio and subatmosheric initial pressure. The experiments have been carried out in a cylindrical tube of diameter 30 mm and the cell size has been determined by using the sooted plate technique. The data of the cell size at subatomospheric pressures have indicated that it is proportional to p0-1.2, where p0 is an initial pressure of the mixtures. Values at the atmospheric pressure have been obtained by extrapolating the obtained subatmosheric values of the cell size, and have been plotted against the equivalence ratio and compared with calculated induction zone length by Westbrook. The fact that the cell size is directly proportional to the induction zone length has been verified for the oxyhydrogen mixture over the range of the equivalence ratio tested. The proportionality factor for this mixture has been found to be 23.3, while that for hydrogen/air mixtures had been found by Knystautas et al. to be 52.2. The critical initiation energies etimated from the cell size data obtained here by utilizing the theoretical model proposed by Lee have been found to be in good agreement with measured critical initiation energies by the critical tube diameter method of Matsui and Lee.