Modeling of shock-induced chemical reactions in powder mixtures

Abstract

Chemical reactions in inorganic powder mixtures under high-pressure shock wave loading are described by two mathematical models, one homogeneous and the other heterogeneous. The models are formulated based upon existing results of observations on post-shock samples of Al-Ni, Al-Ti, and ZnO-Fe2O3 mixtures. Two mechanisms were isolated for the development of the initial models: (1) the creation of a nonequilibrium mixture by dynamic mass mixing, and (2) ensuing chemical reactions. The homogeneous model was evaluated under shock conditions using a one-dimensional wave propagation code, and suggested requisite conditions for the thermal excursion of localized reactions: a localized initial peak temperature of 1000–2000 K and reaction time constants of 1 μs or less. Calculations indicate that reactions occur while the sample is under shock loading, consistent with observations of post-shock samples.