Effect of debris fragments on direct initiation of spherical detonation waves in stoichiometric oxygen/hydrogen mixtures

Paper reports a result of experiments of spherical shock waves generated by explosions of micro-explosives weighing from 1 to 10 mg ignited by the irradiation of Q-switched laser beam and direct initiation to a spherical detonation wave in stoichiometric oxygen/hydrogen mixtures at 10–200 kPa. We visualized the interaction of debris particles ejected micro-explosives’ surface with shock waves by using double exposure holographic interferometry and high-speed video recording. Upon explosion, minute inert debris launched supersonically from micro-charge surface precursory to shock waves initiated spherical detonation waves. To examine this effect we attached 0.5–2.0 μm diameter SiO2 particles densely on micro-explosive surfaces and observed that the supersonic particles, significantly promoted the direct initiation of spherical detonation waves. The domain and boundary of detonation wave initiations were experimentally obtained at various initial pressures and the amount of micro-charges.