中国物理B ›› 2023, Vol. 32 ›› Issue (12): 128201-128201.doi: 10.1088/1674-1056/accd47

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Transient study of droplet oscillation characteristics driven by an electric field

Yan-Fei Gao(高燕飞)1, Wei-Feng He(何纬峰)1,†, Adam Abdalazeem1, Qi-Le Shi(施其乐)1, Ji-Rong Zhang(张继荣)1, Peng-Fei Su(苏鹏飞)2, Si-Yong Yu(俞思涌)1, Zhao-Hui Yao(姚照辉)1, and Dong Han(韩东)1   

  1. 1 Advanced Energy Conservation Research Group(AECRG), College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
    2 Dongfang Turbine Co., Ltd, Deyang 618000, China
  • 收稿日期:2022-12-12 修回日期:2023-03-28 接受日期:2023-04-16 出版日期:2023-11-14 发布日期:2023-11-22
  • 通讯作者: Wei-Feng He E-mail:wfhe@nuaa.edu.cn
  • 基金资助:
    The authors expressed their sincere gratitude to the Natural Science Foundation of Jiangsu Province (Grant No.BK2020194), the Basic Research Fund of Central University (Grant No.NS2022026), and the Graduate Research and Practice Innovation Program (Grant No.xcxjh20220215).

Transient study of droplet oscillation characteristics driven by an electric field

Yan-Fei Gao(高燕飞)1, Wei-Feng He(何纬峰)1,†, Adam Abdalazeem1, Qi-Le Shi(施其乐)1, Ji-Rong Zhang(张继荣)1, Peng-Fei Su(苏鹏飞)2, Si-Yong Yu(俞思涌)1, Zhao-Hui Yao(姚照辉)1, and Dong Han(韩东)1   

  1. 1 Advanced Energy Conservation Research Group(AECRG), College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;
    2 Dongfang Turbine Co., Ltd, Deyang 618000, China
  • Received:2022-12-12 Revised:2023-03-28 Accepted:2023-04-16 Online:2023-11-14 Published:2023-11-22
  • Contact: Wei-Feng He E-mail:wfhe@nuaa.edu.cn
  • Supported by:
    The authors expressed their sincere gratitude to the Natural Science Foundation of Jiangsu Province (Grant No.BK2020194), the Basic Research Fund of Central University (Grant No.NS2022026), and the Graduate Research and Practice Innovation Program (Grant No.xcxjh20220215).

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摘要： Electrowetting technology, a microfluidic technology, has attracted more and more attention in recent years and has broad prospects in terms of microdroplet drive. In this paper, the dynamic contact angle theory is used to develop a numerical model to predict the droplet dynamic contact behavior and internal flow field under electrowetting. In particular, based on the established computational model of droplet force balance, the dynamic process of a droplet under electrowetting is analyzed, including the perspective of pressure variation and force balance inside the droplet. The results show that when the alternating current frequency increases from 50 Hz to 500 Hz, the amplitude of the oscillation waveform after droplet stabilization is 0.036 mm, 0.016 mm, 0.013 mm and 0.002 mm, while the relevant droplet oscillation period T is 11 ms, 4 ms, 2 ms and 1 ms, respectively. It is also found that the initial phase angle does not affect the droplet oscillation amplitude. In addition, the pressure on the droplet surface under alternating current electrowetting increases rapidly to the maximum value with resonant waveform oscillation, and the droplet will present different resonance modes under voltage stimulation. The higher the resonance mode is, the smaller the droplet oscillation amplitude is and the streamline at the interface will present an eddy current, in which the number of vortices matches the resonance mode. A high resonance mode corresponds to a small droplet amplitude, while there are more vortices with a smaller size.

关键词: electrowetting, dynamic contact angle, level set model, droplet oscillation

Abstract: Electrowetting technology, a microfluidic technology, has attracted more and more attention in recent years and has broad prospects in terms of microdroplet drive. In this paper, the dynamic contact angle theory is used to develop a numerical model to predict the droplet dynamic contact behavior and internal flow field under electrowetting. In particular, based on the established computational model of droplet force balance, the dynamic process of a droplet under electrowetting is analyzed, including the perspective of pressure variation and force balance inside the droplet. The results show that when the alternating current frequency increases from 50 Hz to 500 Hz, the amplitude of the oscillation waveform after droplet stabilization is 0.036 mm, 0.016 mm, 0.013 mm and 0.002 mm, while the relevant droplet oscillation period T is 11 ms, 4 ms, 2 ms and 1 ms, respectively. It is also found that the initial phase angle does not affect the droplet oscillation amplitude. In addition, the pressure on the droplet surface under alternating current electrowetting increases rapidly to the maximum value with resonant waveform oscillation, and the droplet will present different resonance modes under voltage stimulation. The higher the resonance mode is, the smaller the droplet oscillation amplitude is and the streamline at the interface will present an eddy current, in which the number of vortices matches the resonance mode. A high resonance mode corresponds to a small droplet amplitude, while there are more vortices with a smaller size.

Key words: electrowetting, dynamic contact angle, level set model, droplet oscillation

中图分类号:  (Surface and interface chemistry; heterogeneous catalysis at surfaces)

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