Numerical simulation of dynamic process for liquid film spreading by lattice Boltzmann method and its experimental verification

LIU Qiu-zu(刘邱祖)^{1, 2}, KOU Zi-ming(寇子明)^{1, 2}, HAN Zhen-nan(韩振南)¹

(1. College of Mechanical Engineering, Taiyuan University of Technology, Taiyuan 030024, China;
2. Shanxi Provincial Engineering Laboratory (Research Center) for Mine Fluid Control
(Taiyuan University of Technology), Taiyuan 030024, China)

Abstract:Combined with the kinetic model of liquid film spreading, a new numerical method of solid-liquid-gas three-phase flow was developed for the moving of contact line, which was a hybrid method of computational fluid dynamics and lattice Boltzmann method (LBM). By taking the effect of molecule force in droplet and the wall surface on liquid film into account, the changing law of contact angle with different surface tensions was analyzed on glass and aluminum foil surfaces. Compared with experimental results, the standard deviation by using LBM is less than 0.5°, which validates the feasibility of LBM simulation on the dynamic process of liquid film spreading. In addition, oscillations are discovered both at the initial and end phases. The phenomenon of retraction is also found and the maximum retraction angle is 7.58°. The obtained result shows that the retraction is proved to be correlative with precursor film by tracking the volume change of liquid film contour. Furthermore, non-dimensional coefficient λ is introduced to measure the liquid film retraction capacity.

Key words:liquid film spreading; contact angle; lattice Boltzmann method (LBM); retraction phenomenon; numerical simulation