超声行波驱动的玻璃表面液滴运动数值模拟

发布时间：2018-06-01 02:34

本文选题：超声行波 + 液滴　；参考：《北京航空航天大学学报》2017年05期

【摘要】：针对液滴铺展和移动的动力学行为在工业生产和微流控芯片等领域有着重要作用,提出了一种基于超声行波理论的弹性体平板驱动模型,利用压电陶瓷的逆压电效应在弹性体玻璃产生超声行波从而驱动液滴运动。借助多物理场软件COMSOL建立液滴模型,首先进行行波分析,验证了驱动液滴的可行性。在0~60 ms中,液滴在超声行波的驱动下进行收缩-铺展的正弦振荡运动。然后通过液滴内部流场结构分析发现,当液滴半径铺展到最大后开始收缩时,液滴与基底接触面处的速度首先发生变化,表明液滴内部速度场的变化对接触线是否发生移动有着重要作用。液滴内部流场存在一个类似于椭圆形的漩涡,说明液滴运动不是单纯由于收缩-铺展而引起的平动,而是滚动着朝前运动。最后分别探讨了液滴移动速度与驱动电压、驱动频率以及动力黏度的关系,结果表明液滴移动速度受动力黏度影响较为显著。
[Abstract]:As the dynamic behavior of droplet spreading and moving plays an important role in industrial production and microfluidic chip, an elastic plate driving model based on ultrasonic traveling wave theory is proposed. The inverse piezoelectric effect of piezoelectric ceramics is used to generate ultrasonic traveling waves in elastomer glass to drive droplet motion. The liquid droplet model is established with the help of multi-physical field software COMSOL. Firstly, the traveling wave analysis is carried out to verify the feasibility of driving the droplet. At 060 Ms, the droplets are driven by ultrasonic traveling waves to contract and spread the sinusoidal oscillations. Then, by analyzing the flow field structure of the droplet, it is found that the velocity at the interface between the droplet and the substrate changes at first when the radius of the droplet reaches the maximum and begins to shrink. It is shown that the variation of the velocity field of the droplet plays an important role in the movement of the contact line. There is an elliptical vortex in the droplet flow field which indicates that the droplet motion is not only caused by contraction and spread but rolling forward. Finally, the relationship between droplet moving speed and driving voltage, driving frequency and dynamic viscosity is discussed. The results show that the droplet velocity is affected by dynamic viscosity.
【作者单位】：华南理工大学机械与汽车工程学院;
【基金】：国家自然科学基金(51275175) 广东省自然科学基金(2014A030313254)~~
【分类号】：O35

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