Modeling of particle compressibility and ignition from shock focusing

Abstract

Two-phase shock-driven reacting flow simulations are conducted to determine the post-detonation shock-focusing ignition and burning of aluminum particle mixtures. A model for aluminum particles that accounts for material compressibility from shock heating and expansion is presented. The Lagrangian description of the particles is incorporated into an Eulerian description of the gas phase resulting in a fully compressible, two-way coupled simulation. Simulations are conducted of an isolated explosive located near a corner to promote ignition of the particles from shock focusing. Parametric studies are conducted to determine the effects of equivalence ratio, particle size, and charge placement, on the post-detonation pressure and impulse. Results highlight the importance of the timing and position of the shock focusing event relative to the local mixture equivalence ratio that results in an optimal equivalence ratio which maximizes impulse for the geometry considered.