Time-sequenced X-ray observation and modeling of a thermal explosion*

The evolution of a thermally-initiated explosion is studied using a multiple-image x-ray system. PBX-9501 is used in this work, enabling direct comparison to recently-published data obtained with proton radiography. For each observed explosion, four x-ray images of the explosive are obtained, each image spaced by tens of microseconds. The multi-physics code, ALE3D, is used to model the pre-ignition thermal profile and post-ignition deflagration of the solid explosive. The model incorporates chemical decomposition, thermal transport, and implicit hydrodynamics to enable accurate prediction of ignition time and temperature. A convective burn model is also implemented in ALE3D to simulate the post-ignition deflagration of thermally-damaged solid energetic materials.