Development of instabilities in explosively dispersed particles

Abstract

Models for explosives containing metal particles must consider the complex gas-particle flow that is generated following detonation of the explosive. Previous experimental studies have shown that when a layer of solid particles is explosively dispersed, the particles often develop a non-uniform spatial distribution. The instabilities within the particles and at the particle layer interface likely form on the timescale of the detonation propagation through the particles. The mesoscale perturbations are manifested at later times in experiments by the formation of clusters of particles or coherent jet-like particle structures which persist for some distance during the dispersal process. These particle jets influence the particle-gas mixing and hence particle reaction rates at the macro scale. The particle instabilities that occur in explosively dispersed particles are investigated with a mesh-free computational method (smoothed-particle hydrodynamics). The simulations are compared with experimental results for the dispersal of a cylindrical packed bed of particles surrounding a central explosive charge. Of particular interest is the effect of the particle density and charge/particle mass ratio on the susceptibility of the particles to form jets. © 2012 American Institute of Physics.