气泡与自由液面相互作用的实验研究

气泡在不同边界附近运动时,其运动特性与在自由场中相比会发生很大变化,特别是当气泡在近自由面附近运动时, 与自由面发生强烈的耦合作用而产生极其复杂的水面现象.为探究其规律,在前人研究的基础上, 采用电火花生成气泡,利用高速摄影系统对气泡与自由液面的相互作用进行了实验观察和研究. 通过对大量实验数据的分析和整理,总结了自由液面的存在对气泡最大半径、脉动周期、射流时间以及射流宽度的影响, 并初步拟合了放电电压与气泡最大半径的关系.对不同水冢现象的具体过程进行了分类和详细的描述, 得出了发生不同水冢现象的决定因素,同时统计得到相同初始条件下水柱最大高度随无量纲距离的变化规律, 为气泡与自由液面相互作用的研究提供了参考.

Experimental study of interaction between bubble and free surface

As a bubble moves near different boundaries, the motion characteristic will change largely compared with the condition of free field, especially near the free surface: there will appear a complex phenomenon because of the interaction. This paper aims to investigate experimentally the phenomenon and the regularity of the interaction between bubble and free surface. Using a spark-generated device and a high-speed camera, the influences of free surface on the maximal radius, period, jet time and width of the bubble are discussed. The relation between the voltage and the maximal radius is obtained. Different typical phenomena near the free surface are observed. The factors inducing different plume phenomena are obtained. Then the regurality of maximal height of the water column varying with dimensionless distance under the same initial condition is obtained, which provides a reference to the research on the interaction between bubble and free surface.