A Mesoscale Modeling Tool for Heterogeneous Explosives with Accurate Multi-Physics Models and Detailed Chemical Kinetics

In the proposed SBIR project, CFDRC will develop an efficient, high-fidelity computational tool to simulate compaction wave propagation and the ensuing multi-physics phenomena in heterogeneous explosives (HEs), including the effects of shock wave on external targets. Physics that will be accurately modeled include: (1) Resolution of subgrain-size hot spots; (2) Granular deformation and packing due to high-speed projectile stimuli; (3) Global kinetics for HE decomposition and detailed kinetics for gas phase reaction; (4) Momentum- and energy-coupling between the moving particles and gas flow; and (5) Deflagration to detonation transition. In Phase I, we will demonstrate feasibility using CFDRC’s advanced flow solver, CoBi, which already includes the following models: (1) Innovative “immersed-particle method” to couple granular motion and gas flow; (2) Finite element method (FEM) to simulate particle deformation; (3) Compressible flow capability including shock wave capturing; and (4) Multi-step chemistry. In Phase I, CoBi will be enhanced by adding condensed- and gas-phase kinetics for HMX, and by coupling the immersed-particle method to the FEM module. In Phase II, the focus will be to improve the accuracy of all models and to make CoBi comprehensive by implementing: (1) Dynamically adaptive mesh refinement for moving shock capturing; (2) A database that provides the user with multiple options for both condensed- and gas-phase kinetics; and (3) Efficient code parallelization. The comprehensive tool will be extensively validated against benchmark cases, and finally demonstrated for problems of interest to OSD.