EVOLUTION OF INDUCTION TIME IN DETONATION CELLS

The evolution of the induction time inside the cell of detonations has been studied by emission spectroscopy of hydroxyl radical. The induction time is always conventionally measured as the time elapsed between the arrival of the shock wave, detected by a pressure gauge, and the reaction zone, detected by the emission intensity of the OH radical. The experimental apparatus used for this study is described in detail. For all the mixtures studied, a similar evolution of the induction time is observed. The local induction time, very short at the apex of the cell, increases all throughout. Detonations propagating in mixtures with identical composition but at different initial pressure produce similar evolution of the induction times. The evolution of the induction time with the composition of the mixture is discussed. The experimental measurements are compared to the theoretical induction time calculating by using a linear isothermal kinetic mechanism, the local induction times computed are in good agreement with experimental data. © 1979.