Simulation of behavior of combustion reaction in non-uniform size particle HMX explosives under drop hammer impact based on 3D-DEM

In practice, macroscopic explosives consist of explosive particles of varying sizes, which are referred to as non-uniform size particle explosives in this paper. It is meaningful to study the ignition and combustion of non-uniform size particle explosives for their safety prediction and control. The present work uses the three-dimensional discrete element method (3D-DEM), to efficiently simulate the behaviors of combustion reaction in non-uniform size particle Cyclotetramethylene tetranitroamine (HMX) explosives under a drop hammer. The apparent pressure, average temperature, reaction thermal power and dissipation power with time have been analyzed, and the differences among the configurations are quantitatively characterized by the total explosive volume and the pore-defect volume. Generally, explosive particles containing defects have higher apparent pressure peaks, and the average temperature increases faster with time. In addition, it is obtained that non-uniform size particle explosives (Configs. B-D and Configs. 2-8) have more dissipation power due to their more pore defects, while uniform particle explosives (Config. A and Config. 1) have higher reaction thermal power due to their higher explosive content. The combustion reaction characteristics of different non-uniform size particles explosives are mainly determined by the explosive content and the size and number of pore defects, that is, an appropriate combination of explosive content and pore defects is more conducive to the ignition and combustion of explosive particles.