静电场中液滴变形及内部流动的研究

Droplet Deformation and its Internal Flow in Electrostatic Field

采用VOF(Volume of Fluid)方法捕捉两相流体的界面,利用漏电介质模型模拟静电场,数值计算并获得了静电场中单个分散液滴在另外一种不相溶黏性液体中的变形与内部流动形态。研究表明:液滴变形的方向及液滴内部循环的方向与液滴的物性参数有关。液滴的变形方向与判断参数fd有关,当fd<0时,液滴沿水平横向被拉伸;当fd>0时,液滴沿垂直方向被拉伸。液滴内部流动方向与判别参数β有关,当β<1时,流动方向为从两极到赤道;当β>1时,流动方向为从赤道到两极。研究结果与前人的理论、试验及数值计算结果进行了对比分析,在变形率较小时,与试验数据、理论以及数值计算均有很好的吻合性;在较大变形率时,与试验数据与数值分析依旧有较好的吻合,与理论分析具有较大差异。

The deformation and internal flow of the single droplet suspended in other vicious fluid under the influence of the electric field were simulated and calculated by adopting VOF（Volume of Fluid） method to track the interface and using leaky dielectric model to simulate the electric field. The calculated results indicate that the directions of deformation and internal flow depend on the physical properties of fluids. The direction of droplet deformation is linked to the assessing coefficient fd ： when fd0 the droplet is stretched along transverse, when fd0 the droplet is stretched along vertical. The internal flow is linked to the assessing coefficient β： when β1 the direction is from the pole to the equator, and when β1 the direction is from the equator to pole. The results were compared with theoretical, experimental and numerical results obtained by predecessors. When the rate of deformation is small, the results are consisted with theoretical, experimental and numerical results. When the rate of deformation is large, the results are consisted with experimental and numerical results but are discrepancy to theory.