Numerical and experimental investigations of interdigital transducer configurations for efficient droplet streaming and jetting induced by surface acoustic waves
Numerical and experimental investigations of interdigital transducer configurations for efficient droplet streaming and jetting induced by surface acoustic waves
复制标题
DOI：
10.1016/j.ijmultiphaseflow.2020.103545
复制
发表时间：
2021-03-01
影响因子：
3.8
通讯作者：
Qing Fu, Yong
中科院分区：
文献类型：
--
作者：
Biroun, Mehdi H.;Rahmati, Mohammad;Qing Fu, Yong
基于表面声波（SAW）的技术最近被探索用于各种传感和微流体应用，并进行了大量的实验研究和SAW流和液固相互作用的数值模拟。然而，由于saw -液滴相互作用和界面现象的复杂物理性质，saw -液滴驱动的液滴界面大变形尚未得到广泛的研究。本文提出了一种基于耦合水平集流体体积（CLSVOF）方法的计算界面跟踪方法，用于模拟液体与声波的相互作用以及液气表面的变形。建立了一个动态接触角边界条件，并通过实验验证了该边界条件的有效性。利用改进的CLSVOF方法，通过分析液体介质内的能量项，研究了液滴的喷射和内部流动行为。此外，通过应用数值模型，研究了两个数字间换能器（IDTs）的结构和位置对液滴驱动的影响，以实现有效的混合、分离和喷射。结果表明，两个完全对齐的idt最适合混合应用。相比之下，两个偏置idt最适合于浓度和分离应用。通过使用一对对齐的idt，可以获得最大喷射速度和最小喷射时间，而使用两个偏移的idt，可以观察到有效的液体混合和喷射，可用于生物打印应用。(c) 2020年Elsevier Ltd.出版
Surface acoustic wave (SAW) based technologies have recently been explored for various sensing and microfluidic applications, and numerous experimental studies and numerical modelling of SAW streaming and liquid-solid interactions have been performed. However, the large deformation of droplet interface actuated by SAWs has not been widely explored, mainly due to the complex physics of SAW-droplet interactions and interfacial phenomena. In this paper, a computational interface tracking method is developed based on the couple level set the volume of fluid (CLSVOF) approach to simulate the interactions between liquid and acoustic waves and deformation of the liquid-air surface. A dynamic contact angle boundary condition is developed and validated by experimental results to simulate the three-phase contact line dynamics. The modified CLSVOF method is then used to study the droplet jetting and internal streaming behaviours by analyzing the energy terms within the liquid medium. Furthermore, by applying the numerical model, effects of configurations and positions of two interdigital transducers (IDTs) on droplet actuation have been investigated to achieve efficient mixing, separation, and jetting. Results show that two perfectly aligned IDTs are optimal for mixing applications. In contrast, two offset IDTs are optimal for concentration and separation applications. The maximum jetting velocity and minimum jetting time are achieved by using a pair of aligned IDTs, whereas by using the two offset IDTs, effective liquid mixing and jetting are observed which can be used in bioprinting applications. (c) 2020 Published by Elsevier Ltd.