相场格子Boltzmann方法模拟载表面活性剂液滴的剪切动态行为

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中图分类号： 0359÷.1 文献标志码：A 文章编号：1000-582X（2025）04-012-17

Phase-field lattice Boltzmann method simulation of shear dynamic behavior of surfactant-laden droplets

CHEN Tao'， YAO Liping'， ZHANG Liangqt2， ZENG Zhong， XIE Shouyong' （1.College of Engineering and Technology， Southwest University， Chongqing 40o715， P.R.China； 2. College of Aerospace Engineering， Chongqing University， Chongqing 400044， P. R. China）

Abstract： Surfactants can reduce fluid interface tension and significantly alter the wetting properties of solid surfaces，making them essential in various industrial applications.To investigate the motion characteristicsof surfactant-laden droplets on solid surfaces，a coupled modelincorporating soluble surfactant flow and contact line dynamics was established using the Cahn-Hillird phase field lattice Boltzmann method， alongside the Yokoi dynamic contact angle model considering the velocity of the three-phase contact line based on experimental data. A computational program was independently developed and optimized with parallel processing to improve computational efficiency. Subsequently， the dynamic behavior of droplets under linear shear flow was studied， focusing on the influence of the effective capillary number and surface wettability on the deformation of both clean and surfactant-laden droplets. The results show that an increase in the efective capilary number promotes droplet deformation， but beyond a critical threshold， the droplet ruptures. Surfactant-laden droplets exhibit greater deformation and faster movement compared to pure droplets.On hydrophilic surfaces， droplets elongate further under shear， with surfactant-laden droplets exhibiting longer relative arc and weting length than their pure counterparts.Conversely，on hydrophobic surfaces，droplets tend to detach under shear， with surfactantladen droplets detaching earlier than pure droplets.These findings indicate that soluble surfactants significantly impact droplet shear dynamics by promoting deformation and increasing movement speed. The numerical methods presented in this study offera robust approach for simulating moving contact line problems in droplets containing soluble surfactants.

Keywords： phase-field method； lattice Boltzmann method； soluble surfactants； shear； droplets

液滴在固体表面上的运动在工业，农业和医学等方面应用广泛，研究其运动特性具有重要的科学和实用价值。（剩余14096字）