A Comparative Study of Two Macro-Scale Models of Condensed-Phase Explosives

Two macro-scale models of high-energy, condensed-phase explosives are considered. The first, called ignition and growth, treats the heterogeneous explosive as a homogeneous mixture of reacting and product species. The second model treats the explosive as two distinct, but interacting, phases. Both models are hyperbolic systems of nonlinear partial differential equations involving balance laws of mass, momentum and energy, and involving assumed constitutive input and reaction kinetics. The two-phase model also involves stiff relaxation terms and nozzling terms that prevent the equations from being cast in conservation form. A high-resolution shock-capturing scheme on overlapping grids, with parallel adaptive mesh refinement, is used to solve the governing equations accurately. The purpose of the paper is to compare solutions of the two models for macro-scale problems involving detonation initiation and diffraction. This is done to illustrate strengths and weaknesses of the models, and to suggest modifications and extensions of the models for further study.