激光空泡在文丘里管中运动的动力学特性

以水为工作介质,在不同文丘里管入口压力下,利用YAG激光器产生的激光轰击水中的金属靶材产生空泡,借助高速摄像系统记录激光空泡在文丘里管中的运动过程,并采用流体动力学模拟对文丘里管中的流场特性和空泡的溃灭特性进行分析.结果表明:激光空泡在文丘里管中的运动,其形状变化可分为产生阶段、挤压阶段、溃灭初始阶段和溃灭阶段等四个阶段.空泡的溃灭取决于流场状态,当流动为层流时,空泡不发生溃灭;当流动为湍流时,空泡发生溃灭,且湍流程度越剧烈,溃灭现象越显著.搭建的激光空泡生成与运动系统能够实现空泡的定点溃灭.

Dynamic characteristics of laser-induced bubble moving in venturi

Laser-induced bubble was generated by YAG laser bombarding the metal target in the water at different venturi inlet pressures. The movement of laser-induced bubble in venturi was recorded by a high-speed video system. Characteristics of flow field in venturi and bubble collapse were analyzed by computational fluid dynamics. Results show that the process of laser-bubble moving in venturi can be classified into four periods: generation, extrusion, initial collapse, and collapse period. Bubble collapse depends on the state of flow field. Bubble does not collapse when the flow is in laminar state. However, bubble collapses when the flow is in turbulent state. The collapse phenomenon becomes prominent with increasing turbulence intensity. The bubble collapse at a fixed point can be realized in the laser-bubble generation and movement system.
Keywords： laser-induced bubble venturi turbulence bubble dynamics