气体密度和初压对炸药爆炸压力衰减的影响

Influence of gas density and initial ambient pressure on attenuation law of explosive explosion pressure

为研究气体密度和初压对爆炸压力的影响,以球形装药为例,在LS-DYNA中模拟不同气体密度、环境初压和真空度条件的TNT炸药爆炸,分析空气冲击波的形成过程和衰减规律。研究结果表明:在爆炸初期冲击波的波阵面位于爆炸产物边界,产物压力与冲击波压力存在强耦合作用;随着爆炸产物自身压力下降,其膨胀速度减慢,冲击波开始与爆炸产物分离,当产物中心压力下降为环境初压时,冲击波与爆炸产物彻底分离,其后以空气冲击波的形式独立传播。降低气体密度可以通过抑制冲击波形成,大幅降低爆炸压力;减小环境初压则通过加快冲击波的衰减速度,也可以在一定程度上降低爆炸压力。相较于单独改变密度和压力,提高真空度对冲击波压力的减小效果更好;近真空环境下无法形成空气冲击波,爆炸压力衰减速度快。

In order to study the influence of gas density and initial ambient pressure on the explosion pressure,taking the spherical charge as example,the TNT explosive explosion under different gas densities,initial ambient pressures and vacuum conditions was simulated in LS-DYNA software to analyze the formation process and attenuation law of air shock wave.The results showed that in the early stages of explosion,the shock wave wavefront located at the explosion product boundary,and there was strong coupling effect in product pressure and shock wave pressure.As the explosion product pressure decreased,the expansion rate slowed down,and the shock wave began to separate from the explosion product.When the central pressure of product decreased to the initial ambient pressure,the shock wave and the explosion product completely separated,after which it propagated independently with the form of air shock wave.Reducing the gas density could significantly reduce the explosion pressure by inhibiting the formation of shock wave,and reducing the initial ambient pressure could reduce the explosion pressure to some extent by accelerating the attenuation rate of shock wave.Compared to changing the density and pressure alone,increasing the vacuum degree had better effect on the shock wave pressure reduction.The near-vacuum environment could not form the air shock wave,and the attenuation rate of explosion pressure was fast.