不同长径比柱形装药水下爆炸冲击波演化规律

Shock wave evolution of cylindrical charge with different slender ratios

为分析药柱形状对水下爆炸冲击波演化的影响。针对圆柱形装药中心起爆问题,在理论上建立了炸药与水交界面上初始冲击波压力及其传播方向的二维计算方法,借助于AUTODYN有限元计算程序开展了长径比1∶2~10∶1的圆柱形TNT在无限水域爆炸的数值模拟,并开展了长径比为1∶1和2.6∶1的圆柱形TNT的水下爆炸试验;对比理论、仿真和试验结果,验证了理论模型的合理性和数值模拟的有效性,分析了柱形装药水下爆炸冲击波的传播规律,重点分析了药柱长径比对不同爆距处冲击波压力分布及传播方向的影响。结果表明:圆柱形装药水下爆炸后,冲击波波阵面逐渐从柱形趋向椭球型再趋向球型,当冲击波传播至10倍无量纲爆距时高压区的转移结束;当长径比大于1∶1时,炸药轴向(端面)的冲击波压力衰减速率大于径向(圆柱面)的衰减速率,冲击波峰值压力随着方向角的增大而单调增长;在1∶1~5∶1的长径比和20倍无量纲爆距范围内,增大药柱长径比可定向增强炸药径向的冲击波压力,药柱的形状对冲击波压力分布影响随着爆距增大而减小。

In order to analyze the influence of charge shape on the evolution of underwater explosion shock wave,a calculation method of initial shock wave pressure and its propagation direction on the interface between explosive and water was established in theory for the problem of center initiation of two-dimensional cylindrical charge.With the aid of AUTODYN finite element program,the tests were conducted with constant-mass cylindrical explosives with slender ratio ranging from 1∶2-10∶1.Experiments on underwater explosion of cylindrical TNT with slender ratio of 1∶1 and 2.6∶1 were carried out.By comparing the theoretical,simulation and experimental results,the effects of the slender ratio on the propagation of the shock wave,the initial shock wave pressure and the pressure distribution in the infinite water were analyzed.The results show that the shock wave front gradually changes from cylindrical shape to ellipsoid shape and then to spherical shape for cylindrical charge exploding underwater.When the shock wave propagates to 10 times of dimensionless detonation distance,the transfer of high-pressure zone ends.When the slender ratio is greater than 1∶1,the decay rate of the shock wave approach the axial(end surface)is greater than that of the radial(cylindrical surface),and the peak pressure of shock wave changes with the direction angle.In the range of 1∶1-5∶1 slender ratio and 20 times dimensionless detonation distance,the radial shock wave pressure of explosive can be enhanced directionally by increasing the slender ratio of explosive,and the influence of the shape charge on shock wave pressure distribution decreases with the detonation distance.