中国空间科学技术

Chinese Space Science and Technology ›› 2025, Vol. 45 ›› Issue (4): 61-69.doi: 10.16708/j.cnki.1000-758X.2025.0058

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Dynamics of droplet transport by electrowetting in different gravity levels

HUO Xiaozhi1,2,3，WANG Qing1,3，GU Junping2，WANG Zhantao4，WANG Qinggong2,*，YU Qiang1,*   

  1. 1.National Space Science Center, Chinese Academy of Sciences，Beijing 100190,China
    2.Qian Xuesen Laboratory of Space Technology, China Academy of Space Technology，Beijing 100094，China
    3.School of Computer Science and Technology，University of Chinese Academy of Sciences，Beijing 100049，China
    4.School of Mechanical & Electronic Engineering, Zhongshan Polytechnic, Zhongshan 528400, China
  • Received:2024-01-11 Revision received:2024-06-11 Accepted:2024-07-05 Online:2025-07-22 Published:2025-08-01

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Abstract: Electrowetting is an effective method for interface manipulation and fluid transport, and it has great application prospects both on Earth and in space due to the advantages of fast response, low power consumption and controllable path. Previously, the influence of gravity is ingnored in the study of the dynamics of droplet transport by electrowetting. However, the gravity must be taken into account when droplets are transported along the direction of gravity or against gravity. Therefore, the dynamics of droplet transport by electrowetting in different gravity levels is studied for space application. In this work, a droplet transport system by electorwentting is designed, and a simulated method of droplet transport by electrowetting is established. In addition, a method of continuous droplet transport is proposed by capturing droplet’s front edge to set activation states of electrodes. Then, the dynamics of long-distance droplet transport by electrowetting is studied in a zero-gravity environment, and the influence of gravity level on droplet transport by electrowetting is analyzed. The continuous and rapiad transport of droplet is achieved using this eletrocwetting system. The simulated results show that the transport velocity of droplet reaches about 0.28m/s. The droplet transport velocity increases almost linearly with the applied voltage. The droplet velocity decreases with the droplet size because the large base diameter of the droplet increases the friction between the droplet and the plate. The gravity’s direction and level affect the droplet’s motion significantly. The droplet deforms under the gravity effect. However, the electrowetting force is still able to overcome the gravity level of -2g, and the electrowetting system shows a good anti-gravity ablity. The constraint laws of droplet transport by electrowetting in different gravity levels are obtained, which provide theoretical basis for droplet collection and tansport in space environment.

Key words: electrowetting, fluid transport, gravity level, numerial simulation, dynamics