Three-dimensional discrete element method to simulate the ignition and combustion of HMX explosives under hot spots

The key to the initiation of condensed explosives is the hot spot which is universally acknowledged. Different hot spots will be produced in explosive particles under different impacts, making quite a discrepancy in the combustion and deflagration processes. In this paper, the ignition and combustion behaviors of the cyclotetramethylene-tetranitramine (HMX) explosive particles under hot spots, and the effect of particle size on the ignition and combustion behavior are developed based on the three-dimensional discrete element method (3D-DEM). The simulation results emphasize that the number of hot spots in the explosive will have an important impact on the ignition and combustion of the explosive. The deflagration performance of the explosive may be inhibited when the number of hot spots generated is too large. In addition, the difference in particle size of explosives can also cause differences in ignition sensitivity and deflagration performance. It is believed that fine explosives are easier to ignite, which is consistent with the experimental observation. The simulation results also reveal a positive correlation between ignition sensitivity and deflagration performance. • The HMX with more hot spots may tend to burn rather than explode. • The HMX with small particle size is more sensitive and has better deflagration. • The apparent pressure of HMX under hot spots is negative at the beginning.