Modeling the Combustion-Deflagration-Detonation Transition (CoDDT) in a porous high explosive, comparison with experiments

A reactive multiphase model stemming from the Baer and Nunziato model was developed and extended to three phases, one solid and two gaseous respectively representing the solid explosive, the initial porosity and the reaction products. It was used to model the transition from deflagration to detonation of a highly confined porous HMX 150–200 explosive thermally initiated, for several initial densities, ranging from 65% to 88% of the material's Theoretical Maximum Density (TMD). The influence of the deconsolidative burning in the critical acceleration of the reactive front was implemented through a fluidization parameter, allowing to switch from pore to grain burning. Other microstructural parameters such as the pores and grains size were determined by careful experimental characterizations presented in Bouchet et al. (2022). The model then succeeded in reproducing the physical mechanisms that were previously experimentally observed, such as the convective burning, the plug formation, and the transition to detonation at the distances that were experimentally measured.