固壁面附近空泡溃灭研究

Experimental Investigations of Laser-induced Cavitation Bubble Collapse Noise Near Solid Boundary

采用自行研制的基于光偏转原理的力学传感器及压电陶瓷探针式水听器PZT,对激光诱导的空泡在固壁面附近溃灭进行了实验研究。结果表明,在脉冲激光作用下,空泡溃灭将依次产生射流和声脉冲,且射流产生时刻早于空泡溃灭时刻;空泡溃灭过程中泡能转换为声能的比例随脉动次数增加而增大;比较实验所得的声脉冲信号和射流信号,得到了声脉冲是空泡第二次溃灭过程中主要衰减方式的结论。

A novel force sensor based on optical beam deflection was developed to investigate the mechan- ical effects of iron sheet during cavitation bubble collapse near solid boundary in water~ The acoustic tran- sient radiated by bubble collapsing is also studied experimentally by PZT hydrophone. The effects of the bubble energy, as well as the dimensionless parameter T（T = L/R,,~x ） ,RBmaxS is the maximum bubble ra- dius and L is the distance of a cavity inception from a boundary） on the acoustic radiation during cavitati- on bubble collapsing near solid wall are analyzed. The experimental results are shown that the target is impacted in turn by laser-generated ablation force and high-speed liquid-jet impulse induced by bubble collapses ~ The liquid-jet formation appears earlier than the acoustic transient. Furthermore, the percent- age of bubble energy turning into the acoustic transient energy increases with the oscillation. Compared the amplitudes of the second liquid-jet with the amplitude of the acoustic transient during the second du- ration, we deduce that the acoustic transient radiated by cavitaion bubble is the main attenuation mode. The results are of values in theoretical and applied research in the laser-matter interaction water.