粉状乳化炸药燃烧转爆轰实验研究与数值模拟

Experimental Research and Numerical Simulation on DDT of Powdered Emulsion Explosives

对粉状乳化炸药进行了燃烧转爆轰实验,结果发现在没有持续热源的情况下,粉状乳化炸药不能自持燃烧。仅在强约束且在一定装药密度范围的情况下,粉状乳化炸药才能发生燃烧转爆轰现象。诱导爆轰距离与装药密度的关系曲线呈“U”型。研究表明,药床密度一定,粉状乳化炸药颗粒粒径越小,诱导爆轰距离愈短。火焰阵面沿轴线的传播速度大于径向传播速度,粉状乳化炸药燃烧前熔化。文中建立了粉状乳化炸药燃烧转爆轰的一维两相流数学模型,对粉状乳化炸药燃烧转爆轰过程进行了数值分析和模拟,结果发现,亚音速和超音速压缩波经过药床时作用效果是不一样的,亚音速压缩波经过药床时,压缩波的初态和终态参数是连续变化的;而超音速压缩波作用下,其初态参数发生突跃。数值模拟表明,诱导爆轰距离、爆速及压力值与实验结果吻合很好,根据模拟结果,对粉状乳化炸药燃烧转爆轰的过程进行了划分。

In this paper, deflagration to detonation transition（DDT）experiments have been carried out on powdery emulsion explosives（PEE）. It is found that PEE is unable to combust constantly by itself without sufficient and continuous heat power supply, and the DDT phenomena hardly occurs in porous beds filled with PEE. The DDT phenomena occurrs only in porous beds with in a certain range of charge density and under strong confinement. The curve of predetonation distance and charge density is U-shaped. The result shows that the smaller the average PEE particle size. the shorter the predetonation distance under certain porous beds density. The axial propagate velocity is higher than that of radial largely for the flame front,so PEE melts before combustion. The one-dimensional and two-phase mathematical model of DDT of emulsion explosive is built in this paper,and the numerical analysis and simulation are implemented for DDT. The results show that the effect of subsonic and ultrasonic on porous beds is different. The initial and final parameters of subsonic compaction wave alter continuously. The initial and final parameters of ultrasonic compaction wave are discontinuous, but its final parameters alter smoothly. For the beds with same volume fraction,the detonation velocity, pressure and particle velocity of non- ideal gas are larger than that of ideal gas distinctly. However,the gas-phase density of ideal gas is larger than that of non-ideal gas. The larger initial volume fraction of porous beds, the greater difference between their detonation parameters. A one-dimension,two phase flow DDT model has been established and the numerical simulation of the DDT process of PEE has been made. The calculated values of predetonation distance, detonation velocity and pressure agree well with the experiments results.