Effects of hysteresis window on contact angle hysteresis behaviour at large Bond number

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:566

Article

Yang, Jiapei¹  Ma, Xiao¹  Fei, Linlin²  Zhang, Xiaoqing¹  Luo, Kai H.³  Shuai, Shijin¹ 

[1] Tsinghua Univ, Sch Vehicle & Mobil, State Key Lab Automot Safety & Energy, Beijing 100084, Peoples R China

[2] Tsinghua Univ, Dept Energy & Power Engn, Ctr Combust Energy, Key Lab Thermal Sci & Power Engn,Minist Educ, Beijing 100084, Peoples R China

[3] UCL, Dept Mech Engn, Torrington Pl, London WC1E 7JE, England

关键词: Lattice Boltzmann method;    Contact angle hysteresis;    Multiphase flow;    Bond number;   

DOI  :  10.1016/j.jcis.2020.01.042

来源: Elsevier

【 摘 要 】

Contact angle hysteresis, defined as the difference between advancing and receding contact angles, is an important phenomenon in multiphase flow on a wetting surface. In this study, a modified pseudo-potential lattice Boltzmann (LB) multiphase model with tunable surface tension is proposed, which is further coupled with the geometrical formulation contact angle scheme to investigate the motion of droplets invoking the contact angle hysteresis. We focus on the dynamic behaviour of droplets driven by a body force at the Bond number ranging from 1 to 6, which is defined as the ratio of the body force to the capillary force. The droplet morphology change is examined by varying (i) the Bond number and (ii) the hysteresis window. Results show the droplet morphology evolution can be classified into different stages, including stretch, relaxation, and equilibrium. The droplet oscillation phenomenon at large Bond numbers at the equilibrium stage is observed for the first time. In addition, it is found that such oscillation can lead to the breakup and/or coalescence of droplets when the surface waves spread on the top of the droplet. Furthermore, there is slight oscillation of the normalized length, width and height at the equilibrium stage for the neutral hysteresis window while more dramatic oscillation will appear for the hydrophobic hysteresis window. (C) 2020 Elsevier Inc. All rights reserved.

【 授权许可】

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