LBM Simulation of Two Droplets Merging and Bouncing at the Top of an Inclined Plane with a Wetting Gradient

doi:10.19596/j.cnki.1001-246x.8607

Abstract

Abstract:

Based on lattice Boltzmann method(LBM), the process of droplets merging and bouncing at the top of inclined plane with wetting gradient was simulated. The effects of wetting gradient, wettability at the top of inclined plane, droplet size and Bond number on droplet merging and bouncing process were investigated. The calculation results show that the two droplets can bounce when merged under the action of non-equilibrium tension on a hydrophobic gradient slope. Both the droplet fusion velocity and the maximum jump height increase with the increase of wetting gradient. The maximum droplet jump height decreases with the increase of the wettability of the inclined surface. There is an optimal droplet size that optimizes the maximum jump height. The larger the Bond number, the smaller the maximum droplet jump height.

Key words: lattice Boltzmann method, droplets, merging bounce, wetting gradient, jumping height

Ming GAO, Lu CHEN, Jia LIANG, Dongmin WANG, Yugang ZHAO, Lixin ZHANG, Quan SUN, Haojie LI. LBM Simulation of Two Droplets Merging and Bouncing at the Top of an Inclined Plane with a Wetting Gradient[J]. Chinese Journal of Computational Physics, 2023, 40(3): 333-342.

Figures/Tables 11

Fig.1 Young-Laplace law verification

Fig.2 Relationship between fluid-solid interaction coefficient and contact angle

Fig.3 Comparison of simulation results of bounce height

Fig.4 Physical model

Fig.5 Process of two droplets merging and bouncing at the top of inclined plane under different wetting gradients

Fig.6 Change of droplet bounce height with time under different wetting gradients (r=20 lu, Bo=0.0146, θst=124.2°)

Fig.7 Process of two droplets merging and bouncing at different contact angles at the top of inclined plane

Fig.8 Change of droplet bounce height with time at different contact angles at the top of inclined plane (r=20 lu, Bo=0.0146, Δθg=6.5°/14 lu)

Fig.9 Velocity field of droplet movement at different contact angles at the top of inclined plane (r=20 lu, Bo=0.0146, Δθg=6.5°/14 lu)

Fig.10 Change of droplet bounce height with time at different size

Fig.11 Change of droplet bounce height with time under different Bond numbers

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