凝聚相炸药爆轰波冲击空穴塌陷过程的高精度数值模拟

利用高精度数值格式对凝聚相炸药爆轰波冲击空穴塌陷过程进行了研究. 采用RGFM和Level-set相结合的物质界面处理方法,克服了爆炸流场中高密度比、高压强比的物质界面容易引起数值振荡这一问题. 采用5阶WENO高精度有限差分格式进行空间离散,采用3阶TVD Runger-Kutta法进行时间离散,开发了高精度动态并行程序,并运用该程序对凝聚相炸药爆轰波冲击空穴后的塌陷过程进行了数值模拟,给出了PBX-9404炸药在不同入射压力下的起爆距离及冲击起爆过程中的压力历史曲线图,并分别与实验结果对比后进行了验证. 对凝聚相炸药中的空穴塌陷过程进行了高精度数值计算,给出了不同时刻的密度、压力和粒子速度云图,研究结果表明由于空穴的存在,爆轰波的传播过程中会在空穴处形成射流现象以及密度和能量的汇聚,进一步产生高温高压的热点. 

High Resolution Numerical Simulation of Detonation Wave Shock-Induced Void Collapse in Condensed Explosives

The detonation wave shock-induced collapse of voids in condensed explosives was studied. Combining RGFM with Level-set method for the material interface, the nonphysical oscillation problem was overcome, which caused by high-density ratio and high-pressure ratio between material interfaces. Taking a third-order TVD Runge-Kutta method for time scattering and the fifth-order high-resolution weighted essentially non-oscillatory (WENO) finite difference scheme for space scattering, a parallel solver was developed to simulate the collapse of voids in condensed explosives. Firstly, the detonation distance with different incident pressure and the pressure history curves with the impact initiation process were presented, and then compared with the experimental results. Further the code was used to simulate the void collapse process, and the density, pressure and particle velocity contours in different moments were given. With the density and energy convergence, the jet phenomenon formed can be clearly seen in the hole, and then further form a hot spot in high temperature and high pressure.