近壁面电火花空泡运动特性的高速摄影研究

Experimental Study on the Movement Characteristics of Spark-induced Cavitation Bubble with a Wall by High-speed Photography

利用高速摄技术对电火花诱发的空化泡在发展过程中受壁面影响下的运动过程进行了实验观测。研究了空化泡在壁面附近的演变和空化泡受壁面作用下的溅射现象以及反弹现象。结果表明:在泡-壁无量纲距离γ<3的条件下,空化泡在膨胀阶段并未向刚性壁面发生移动,当空化泡进入收缩阶段后开始向壁面运动;实验还表明随着γ的增大,空化泡向壁面运动的速度减小。通过较高的拍摄频率对近壁面空化泡发展后期运动过程进行了拍摄,实验表明当泡-壁距离γ(γ≈1)较小时,空化泡受壁面影响出现了溅射流与反射流现象。

Experiments were carried out with high-speed photography to observe the developing course of spark-induced cavitation bubble under the impact of the nearby wall. Then,research was made to study the evolution of cavitation bubble near the wall,the sputtering phenomenon as well as the rebounding phenomenon. Result showed that on the condition that the bubble-wall dimensionless distance is less than three( γ < 3),Cavitation bubble does not move towards the rigid wall in the expansion stage,but starts moving to the rigid wall in the contraction stage. The experiment also showed that as γ increases,cavitation bubble moves decreasingly to the rigid wall. At the same time,the late movement process of cavitation bubble near the wall is filmed with higher photo-frequency,and experiment showed that when the bubble-wall dimensionless distance γ( γ ≈ 1) is relatively shorter,phenomenon of sputtering and rebounding is spotted on cavitation bubbles due to the effect of the rigid wall appeared.