A reaction progress variable modeling approach for non-ideal multiphase explosives

This study concerns the development of a mixture fraction based reaction progress variable formulation for aluminized explosives. Highlights of the formulation include a fully compressible treatment of both the gas and solid phases (both aluminum and alumina), heterogenous and homogenous reactions, and effects of group combustion. Isolated particle simulations are validated against experimental data and DNS and show good agreement of burn times over a range of pressure and oxygen environments. The new models are implemented in the CTH shock physics code using a fractional step approach to allow for efficient computation of particle dynamics. Comparisons are made to experimental pressure data for a thermobaric explosive in the Sandia Explosive Components Facility (ECF). Parametric studies are conducted to determine pressure response and impulse to charge equivalence ratio and particle size. Overall good agreement is observed between simulation predictions of pressure time history and impulse.