电润湿效应控制介质上液滴运动的数值模拟

Numerical prediction of the droplet dynamic control of electro-wetting on dielectric(EWOD)

电润湿效应是利用电极阵列所产生的变化电场,改变液滴表面张力,实现控制液滴在微小通道内的运动。本文采用数值模拟方法模拟液滴在介质上的电润湿效应。用level set函数方法捕捉液滴表面,得到表面张力,通过压力方程和N-S方程依次求解压力场和速度场。采用3×3的电极方阵控制液滴运动,数值结果表明电润湿效应能在较低电压下,实现对液滴移动的控制。并给出液滴可移动的电极间距极限值100μm。

Electro- Wetting On Dielectric（EWOD） device introduces the electrodes arrays to define the variational electric field, modify the droplet surface tension, and control the movement of droplet in microchannel. EWOD is calculated in numerical method. Level set method is used to capture the free surface and solve the surface tension equation. Together with pressure equation and N - S equation, the pressure field and velocity field are calculated. The 3 × 3 electrodes arrays are utilized to drive the droplet. The result of simulation predicts that the Electro - Wetting make the droplet move on the special track at lower voltage. If the interval of electrodes large than a critical value 100μm, leading the droplet movable from one electrode to next, is calculated in simulation.