Informing Ignition and Growth Model Reaction Rates with Mesoscale Simulations of High Explosive Mixtures

Macroscopic reaction rates are one the most complicated components of continuum reactive flow models for heterogeneous high explosives (HE). They are influenced not only by chemistry but also by thermomechanical properties, microstructure, and shock conditions. In this study, we perform mesoscale simulations with the multi-physics hydrocode, ALE3D, to investigate the shock-induced response of HE mixtures and predict their reaction rates. The Cheetah thermochemical code is used as an in-line driver providing the equation-of-state and kinetic properties for the energetic constituents. Microstructures are generated computationally with grain geometry set using a Voronoi tessellation algorithm and pores positioned randomly in the simulation domain. Mesoscale reaction rates are computed from simulations for a range of HE mixture ratios, applied pressures, porosity, and pore sizes; these simulations are used to inform Lee-Tarver Ignition and Growth reactive flow model parameters. Select parameter sets are used in shock initiation studies and compared to experimental data. These studies underpin predictive formulation-sensitive reactive flow models for HE mixtures.

 

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344. LLNL-ABS-843783.