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

2,4-二硝基苯甲醚(DNAN)/奥克托今(HMX)熔铸炸药在烤燃过程中会发生DNAN熔化、HMX晶型转变等特征现象。为研究其烤燃响应特性，发展了DNAN熔化-化学反应动力学模型，结合HMX四步化学反应动力学模型，从宏观和细观尺度研究了DNAN基熔铸炸药的熔化、晶型转变及点火响应。宏观计算结果表明：DNAN在约377.00 K熔化，HMX在约450.00 K晶型转变，点火温度为531.34 K，点火位置位于装药上下端面与侧面夹角处环形区域，计算点火时间与实验结果误差为0.5%。基于宏观点火区域进行细观计算，发现点火位置位于HMX炸药晶粒，并得到DNAN熔化、HMX晶型转变等细观分布演化规律，即不同时刻，液相DNAN统计分布呈U形分布，δ-HMX近似正态分布。表明DNAN基熔铸炸药烤燃宏细观数值计算对深入理解含能材料的热点火机理具有重要意义。

Macro-meso-scale Cook-off Simulations of DNAN-based Melt-cast Explosives

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.