表面张力对固壁旁空泡运动特性影响的理论和实验研究

The effect of surface tension on bubble oscillation near a rigid boundary

表面张力是影响空泡脉动及空蚀的一个重要因素.对五种不同表面张力液体中空泡脉动(膨胀和收缩)过程进行了研究,并将实验结果与基于空泡生长和溃灭理论的计算结果进行了对比.实验中,用激光作为测试光源,采用光偏转测试系统研究了不同表面张力液体中空泡泡壁运动规律及泡壁速度的变化.结果表明:表面张力对空泡膨胀过程起抑制作用,故液体表面张力愈大,空泡能达到的最大直径越小;表面张力对空泡的收缩过程则起加速作用,液体表面张力愈大,收缩越迅速,空泡泡壁运动速度越大,其所产生的瞬时溃灭压强越大,空化效果越好.

The surface tension of a liquid is one of the basic factors determining cavitation and cavitation erosion. The expansion and contraction of cavitation bubble in liquids with different surface tensions are investigated experimentally, which are compared with theoretical analyses based on Rayleigh-Plesset equation. In the experimental study, cavitation bubble is induced by a laser pulse, the spatial evolution and velocity of the bubble wall in liquids with different surface tensions are detected by a fiber-optic diagnostic technique based on optical beam deflection. Experimental results show that the surface-tension forces hinder the bubble growth progress, so increasing surface-tension decreases the maximum bubble radii. On the other hand, the surfacetension forces speed up bubble collapse process. In larger surface tension cases, the bubble velocity is higher, and higher erosive power is produced.