基于兰姆波在倾斜镜子基板上的油水微分离实验*

该文提出利用兰姆波在倾斜的镜子基板上推动油水混合液滴,实现油水的微分离。实验主要研究了油水混合液滴在分离过程中的运动位移特性关系。运用Navier-Stokes、声流力等方程进行理论分析,发现混合液滴在分离过程中水滴所受到的驱动力大于油滴。通过对实验多变量的控制、单一变量的研究、建立油水混合液滴在倾斜镜子基板上受力平衡方程,发现激发电压、油水混合比例、基板倾角三个因素对油水微分离位移实验有着重要的影响。结果表明:当基板倾角和油水混合比例一定时,油水分离位移随着激发电压的增大而减小;在激发电压和基板倾角不变时,油水分离位移随着油水混合比例的减小而减小;当激发电压和油水混合比例不变时,油水分离位移随着基板倾角的增大而减小。该油水分离方法可以被应用到其他非压电基板上,为获得其他两种不相溶混合液滴的分离提供技术支持。

Experimental investigation on separation of oil from a microliter oil/water mixed drop using Lamb waves on an inclined mirror substrate

In this paper, Lamb wave has been applied to separate oil from a microliter oil/water mixed droplets on an inclined mirror substrate. The experiment mainly investigated the separation displacement characteristics of oil/water mixed droplet in the separation process. Using the equations of Navier-Stokes and acoustic streaming force, the theoretical analysis and explanation of results show that the driving force of the water droplet in the separation process is greater than the oil droplet. According to the control of experimental multivariables, the study of single variables, establishing the balance equation with the force of oil/water mixed droplet on the inclined mirror substrate, three main factors are demonstrated which influence the separation displacement, the excitation voltage, the plate inclination, and the oil/water volume ratio. It is found that under a certain oil/water volume ratio and a certain inclination of substrate, the separation displacement decreases with the increase in the input power. Under a certain excitation voltage and a certain inclination angle, the smaller the oil/water volume ratio, the shorter the separation displacement. When the oil/water volume ratio and the excitation voltage are fixed, the larger the inclination angle, the faster the separation.