SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2022, Vol. 52 ›› Issue (12): 66-77.DOI: 10.1016/j.cjche.2021.11.001

• Full Length Article • 上一篇    下一篇

Impingement and mixing dynamics of micro-droplets on a solid surface

Guina Yi1,2, Ziqi Cai1,2, Zhengming Gao1,2, J.J. Derksen3   

  1. 1. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China;
    2. State Key Laboratory of Chemical Resource Engineering, School of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China;
    3. School of Engineering, University of Aberdeen, Aberdeen AB24 3UE, UK
  • 收稿日期:2021-07-30 修回日期:2021-10-28 出版日期:2022-12-28 发布日期:2023-01-31
  • 通讯作者: Ziqi Cai,E-mail:caiziqi@mail.buct.edu.cn;Zhengming Gao,E-mail:gaozm@mail.buct.edu.cn
  • 基金资助:
    The authors gratefully acknowledge the financial support from National Natural Science Foundation of China (22078008, 22178014) and the Fundamental Research Funds for the Central Universities (XK1802-1).

Impingement and mixing dynamics of micro-droplets on a solid surface

Guina Yi1,2, Ziqi Cai1,2, Zhengming Gao1,2, J.J. Derksen3   

  1. 1. Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China;
    2. State Key Laboratory of Chemical Resource Engineering, School of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China;
    3. School of Engineering, University of Aberdeen, Aberdeen AB24 3UE, UK
  • Received:2021-07-30 Revised:2021-10-28 Online:2022-12-28 Published:2023-01-31
  • Contact: Ziqi Cai,E-mail:caiziqi@mail.buct.edu.cn;Zhengming Gao,E-mail:gaozm@mail.buct.edu.cn
  • Supported by:
    The authors gratefully acknowledge the financial support from National Natural Science Foundation of China (22078008, 22178014) and the Fundamental Research Funds for the Central Universities (XK1802-1).

摘要: The hydrodynamics and mixing during the nonaxisymmetry impingement of a micro-droplet and a sessile droplet of the same fluid are investigated by many-body dissipative particle dynamics (MDPD) simulation. In this work, the range of the impingement angle (θi) between the impinging droplet and the sessile droplet is 0°–60° and the contact angle is set as 45° or 124°. The droplets impingement and mixing behavior is analyzed based on the droplet internal flow field, the concentration distribution and the time scale of the decay of the kinetic energy of the impinging droplet. The dimensionless total mixing time (τm) is calculated by a modified mixing function. With the Weber number (We) ranging from 5.65 to 22.7 and the Ohnesorge number (Oh) ranging from 0.136 to 0.214, we find τm hardly changes with We and Oh. Whereas, θi and surface wettability are found to have a significant effect on τm. We find that θi has no clear effect on τm on a hydrophobic surface, while on the hydrophilic surface, τm increase with the θi. Thus, reducing the impinging angle is a valid method to shorten the τm.

关键词: Droplets impingement, Mixing behavior, Mixing time, Concentration distribution, Many-body dissipative particle dynamics

Abstract: The hydrodynamics and mixing during the nonaxisymmetry impingement of a micro-droplet and a sessile droplet of the same fluid are investigated by many-body dissipative particle dynamics (MDPD) simulation. In this work, the range of the impingement angle (θi) between the impinging droplet and the sessile droplet is 0°–60° and the contact angle is set as 45° or 124°. The droplets impingement and mixing behavior is analyzed based on the droplet internal flow field, the concentration distribution and the time scale of the decay of the kinetic energy of the impinging droplet. The dimensionless total mixing time (τm) is calculated by a modified mixing function. With the Weber number (We) ranging from 5.65 to 22.7 and the Ohnesorge number (Oh) ranging from 0.136 to 0.214, we find τm hardly changes with We and Oh. Whereas, θi and surface wettability are found to have a significant effect on τm. We find that θi has no clear effect on τm on a hydrophobic surface, while on the hydrophilic surface, τm increase with the θi. Thus, reducing the impinging angle is a valid method to shorten the τm.

Key words: Droplets impingement, Mixing behavior, Mixing time, Concentration distribution, Many-body dissipative particle dynamics