Effects of Adiabatic Gas Compression on Energy Localization and Ignition of High Explosives During the Final Stages of Deflagration-to-Detonation Transition

Deflagration-to-detonation transition (DDT) is an insidious hazard response mode in high explosives (HEs) whereby a mild sub-sonic deflagration in a porous bed of material under confinement transitions to a supersonic detonation. The final stages of DDT is hypothesized to involve shocks in semi-compacted material. While previous mesoscale studies of DDT have explored compaction and reactions in porous beds, no previous studies have investigated the effect of adiabatic gas compression on energy localization in solid HE. In this study, multi-physics simulations are performed to determine how changes to porosity, mild shock conditions, binder thickness, and pore gas influences energy localization and ignition in coated HE grains. Different energy localization mechanisms such as plastic work heating, shear bands and heating via pore gas compression with thermal conduction are explored. Pores are filled with air, HE gas products or are unfilled (vacuum). The competition of adiabatic gas compression and plasticity-viscous mechanisms is discussed. Insights from studies will improve our understanding of DDT and key parameters that influence it.



LLNL-ABS-2002474.