Numerical study on the dispersal effect of solid detonation products on the blast-wave propagation

This study explored the practicality of using a two-phase flow model to study particles interacting with the shock/blast waves. Numerical data were compared with previous experimental results on particle dispersal by explosives. The validation results agreed well with the experimental data when the frictional–collisional pressure was appropriately modeled. Next, the properties of the solid detonation products of Pb(N3)2 during an unconfined explosion and an explosion in an inner-grooved straight tube were examined. The detonation products were separately modeled using the ideal gas equation of state (for compressible nitrogen) and a continuum–kinetic theory granular model (for Pb particles). For comparison, the detonation products were also modeled as compressible gas only. The peak overpressure distributions in the unconfined explosion were independent of the modeling method for the detonation products. Because the Pb particles were highly diluted by the three-dimensional expansion, they did not affect the blast-wave propagation. As for the explosion in the tube, the volume fraction of the Pb particles was kept high inside the tube. The supersonic gas jet from the tube created a complex flow with a Mach disk behind the incident shock wave. The particles heated the gas toward the outside, resulting in a higher-energy gas passing through the Mach disk and causing a stronger secondary shock wave, which was coupled with the incident shock wave. When the Pb particles were considered in modeling, the numerical results became more consistent with the experimental data than those obtained without Pb particle modeling.