激光作用铝靶爆轰波流场观测与理论分析

Experimental observation and theoretical analysis of detonation wave evolution induced by laser ablating aluminum target

进行了强激光作用铝靶实验,采用纹影照相法,观察爆轰波流场演化过程,分析了爆轰波衰减规律。根据冲击波运动的自相似性,采用点爆炸模型描述了激光作用下爆轰波流场的演化,计算了波阵面速度、压力和温度。结果显示:爆轰波阵面沿迎着激光光源方向较快传播,波阵面形状由最初的半椭球形逐渐向半球形转变,在演化过程中扰动区结构复杂,存在多个密度间断层。在爆轰波开始传播阶段,波阵面的压力和温度较高但下降很快。

A experiment of laser ablating aluminum target was conducted. A schlieren photography technique was employed for visualizing temporal evolution of detonation waves and analyzing detonation wave attenuation law. Based on similitude theory of shockwave motion, a point explosion model was used to describe detonation-wave evolution induced by laser ablating aluminum target. The propagation speed, pressure and temperature of the wave front were calculated. The results show that the detonation wave has a high speed towards laser source. The wave front transform from half-elliptical in early evolution stage into half-spheri- cal. The disturbed zone has a complicated structure and multi-density discontinuities during the flow-field evolution. In the initial stage of detonation-wave propagation, the shockwave has a high pressure and temperature, but they decrease rapidly.