中国物理B ›› 2022, Vol. 31 ›› Issue (4): 46801-046801.doi: 10.1088/1674-1056/ac22a0

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Numerical simulation of two droplets impacting upon a dynamic liquid film

Quan-Yuan Zeng(曾全元)1,2, Xiao-Hua Zhang(张小华)1,2,†, and Dao-Bin Ji(纪道斌)3   

  1. 1 Three Gorges Mathematical Research Center, China Three Gorges University, Yichang 443002, China;
    2 College of Science, China Three Gorges University, Yichang 443002, China;
    3 Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang 443002, China
  • 收稿日期:2021-06-02 修回日期:2021-07-23 接受日期:2021-09-01 出版日期:2022-03-16 发布日期:2022-03-10
  • 通讯作者: Xiao-Hua Zhang E-mail:zhangxiaohua07@163.com
  • 基金资助:
    Project supported by the Engineering Research Center of Eco-environment in the Three Gorges Reservoir Region (Grant No. KF2019-10).

Numerical simulation of two droplets impacting upon a dynamic liquid film

Quan-Yuan Zeng(曾全元)1,2, Xiao-Hua Zhang(张小华)1,2,†, and Dao-Bin Ji(纪道斌)3   

  1. 1 Three Gorges Mathematical Research Center, China Three Gorges University, Yichang 443002, China;
    2 College of Science, China Three Gorges University, Yichang 443002, China;
    3 Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang 443002, China
  • Received:2021-06-02 Revised:2021-07-23 Accepted:2021-09-01 Online:2022-03-16 Published:2022-03-10
  • Contact: Xiao-Hua Zhang E-mail:zhangxiaohua07@163.com
  • Supported by:
    Project supported by the Engineering Research Center of Eco-environment in the Three Gorges Reservoir Region (Grant No. KF2019-10).

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摘要： The impact of droplets on the liquid film is widely involved in industrial and agricultural fields. In recent years, plenty of works are limited to dry walls or stationary liquid films, and the research of multi-droplet impact dynamic films is not sufficient. Based on this, this paper employs a coupled level set and volume of fluid (CLSVOF) method to numerically simulate two-droplet impingement on a dynamic liquid film. In our work, the dynamic film thickness, horizontal central distance between the droplets, droplets' initial impact speed, and simultaneously the flow velocity of the moving film are analyzed. The evolution phenomenon and mechanism caused by the collision are analyzed in detail. We find that within a certain period of time, the droplet spacing does not affect the peripheral crown height; when the droplet spacing decreases or the initial impact velocity increases, the height of the peripheral crown increases at the beginning, and then, because the crown splashed under Rayleigh-Plateau instability, this results in the reduction of the crown height. At the same time, it is found that when the initial impact velocity increases, the angle between the upstream peripheral jet and the dynamic film becomes larger. The more obvious the horizontal movement characteristics, the more restrained the crown height; the spread length increases with the increase of the dynamic film speed, droplet spacing and the initial impact velocity. When the liquid film is thicker, more fluid enters the crown, due to the crown being unstable, the surface tension is not enough to overcome the weight of the rim at the end of the crown, resulting in droplets falling off.

关键词: two droplets, moving liquid film, CLSVOF, mechanism analysis

Abstract: The impact of droplets on the liquid film is widely involved in industrial and agricultural fields. In recent years, plenty of works are limited to dry walls or stationary liquid films, and the research of multi-droplet impact dynamic films is not sufficient. Based on this, this paper employs a coupled level set and volume of fluid (CLSVOF) method to numerically simulate two-droplet impingement on a dynamic liquid film. In our work, the dynamic film thickness, horizontal central distance between the droplets, droplets' initial impact speed, and simultaneously the flow velocity of the moving film are analyzed. The evolution phenomenon and mechanism caused by the collision are analyzed in detail. We find that within a certain period of time, the droplet spacing does not affect the peripheral crown height; when the droplet spacing decreases or the initial impact velocity increases, the height of the peripheral crown increases at the beginning, and then, because the crown splashed under Rayleigh-Plateau instability, this results in the reduction of the crown height. At the same time, it is found that when the initial impact velocity increases, the angle between the upstream peripheral jet and the dynamic film becomes larger. The more obvious the horizontal movement characteristics, the more restrained the crown height; the spread length increases with the increase of the dynamic film speed, droplet spacing and the initial impact velocity. When the liquid film is thicker, more fluid enters the crown, due to the crown being unstable, the surface tension is not enough to overcome the weight of the rim at the end of the crown, resulting in droplets falling off.

Key words: two droplets, moving liquid film, CLSVOF, mechanism analysis

中图分类号:  (Surface tension and related phenomena)

  • 68.03.Cd
68.15.+e (Liquid thin films) 68.35.Md (Surface thermodynamics, surface energies) 68.05.Cf (Liquid-liquid interface structure: measurements and simulations)