2, 4-二硝基苯甲醚基熔铸炸药宏细观烤燃响应特性数值分析

The melting of DNAN and the phase transformation of HMX crystal occur in 2, 4-dinitroanisole (DNAN)/octogen (HMX) melt-cast explosives during cook-off test. A melting reaction kinetics model is developed for DNAN, and a four-step reaction kinetics model of HMX is used to study the melting, phase transformation and ignition response of DNAN-based melt-cast explosives at the macro-meso scale. Macroscale calculation shows that DNAN melts at about 377.00 K, HMX undergoes a phase transformation at about 450.00 K, and the ignition temperature is 531.34 K. The ignition position locates at the annular area between the upper and lower ends and the side of the explosive, the error between the calculated and experimental ignition times is 0.5%. The mesoscale calculation results based on the macroscopic ignition area show that the ignition position locates at HMX crystal, and the evolution rules of DNAN melting and HMX phase transformation are obtained: at different times, the statistical distribution of liquid-phase DNAN is U-shaped, and δ-HMX is approximately normal. The macro-meso scale cook off simulations of DNAN-based melt-cast explosives are of great significance for understanding the thermal ignition mechanism of energetic materials.