Jia Ning, Qing-Yun Huang, Chen-Hui Gai, Yi-Zhan Ding, Bing Zhang, Yu-Lin Lei, Yang Wu, Hong Hu
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引用次数: 0
摘要
微流控技术的快速发展极大地凸显了表面声波(SAW)在微流控中的作用。声表面波影响液滴操作,诱发界面不稳定性以及液滴分裂、喷射和雾化等过程,这些一直是研究的重点。以往的研究发现,这些不稳定机制与三个关键参数密切相关:与压电基底热效应相关的马兰戈尼数 (Ma);与压电基底滑移相关的滑移系数 (β0);以及声毛细管数 (C)。鉴于高宽比(H/L,其中 H 是液滴的特征高度,L 是特征宽度)与雾化尺寸之间的密切联系,本研究全面探讨了这些因素对液滴高宽比 H/L 的综合影响。具体来说,声学毛细管数 C 和滑移系数 β0 的增加会促进液滴高度(H)的降低和向外扩展(L),而马兰戈尼数 Ma 则会抵消这种扩展,使 H/L 值保持较大。当 C 和 β0 值较小时,这种抑制作用尤为明显,但随着 C 和 β0 值的增加,这种抑制作用会逐渐减弱。此外,C 和 β0 值越大,H/L 比值的收敛速度越快,而 Ma 值则会降低这种收敛速度。通过 Ma、β0 和 C 的协调相互作用,可以在很大范围内实现液滴长宽比 H/L 的多维微调。
Numerical study of thermocapillary and slip effects on interfacial destabilization under surface acoustic waves
The rapid development of microfluidics has significantly highlighted the role of surface acoustic waves (SAWs) in microfluidic actuation. SAW influences droplet manipulation, inducing interface instability and processes such as droplet splitting, jetting, and atomization, which have been key research focal points. Previous studies have identified a close correlation between these instability mechanisms and three critical parameters: the Marangoni number (Ma), associated with piezoelectric substrate thermal effects; the slip coefficient (β0), related to piezoelectric substrate slip; and the acoustic capillary number (C). Given the intimate link between the aspect ratio (H/L, where H is the characteristic height, and L is the characteristic width of droplets) and atomization size, this study comprehensively investigates the combined effects of these factors on the droplet aspect ratio H/L. Specifically, increases in the acoustic capillary number C and slip coefficient β0 promote reductions in droplet height (H) and outward expansion (L), while the Marangoni number Ma counteracts this expansion, maintaining larger H/L values. This inhibitory effect is particularly pronounced when C and β0 are small but diminishes as their values increase. Additionally, higher values of C and β0 accelerate the convergence of the H/L ratio, whereas Ma decreases the rate of this convergence. Through the coordinated interplay of Ma, β0, and C, multidimensional and fine-tuned adjustments of the droplet aspect ratio H/L over a wide range can be achieved.