含表面活性剂的多相流模拟算法
01
表面活性剂
表面活性剂的分子结构具有两亲性，其头部亲水，尾部疏水，在水/油两相的界面上能定向排列，使两相的表面相当于转入分子内部，降低了表面张力，进而强烈地影响多相流中发生的现象。例如，它们能强烈地影响在混合物中形成的水滴或气泡的数量、雾化、聚并和破裂现象。
02
模拟的难点
图2 多相流场与表面活性剂复杂的相互作用
03
数值算法
图3 初始化设置：模拟含表面活性剂的双液滴在平板剪切流中的动态行为
图4 未加入表面活性剂时双液滴融合
图5 加入表面活性剂后，液滴的融合受到了抑制
图6 液滴的变形率D随时间的变化曲线
图7 Guido等人观察到的加入表面活性剂时双液滴的聚并行为
参考文献
[1] Chen YS, Lu YL, Yang YM, Maa JR. Surfactant effects on the motion of a droplet in thermocapillary migration. Int J Multiph Flow 1997;23:325–35. https://doi.org/10.1016/S0301-9322(96)00066-3.
[2] Cleret de Langavant C, Guittet A, Theillard M, Temprano-Coleto F, Gibou F. Level-set simulations of soluble surfactant driven flows. J Comput Phys 2017;348:271–97. https://doi.org/10.1016/j.jcp.2017.07.003.
[3] Kian Far E, Gorakifard M, Fattahi E. Multiphase Phase-Field Lattice Boltzmann Method for Simulation of Soluble Surfactants. Symmetry 2021;13:1019. https://doi.org/10.3390/sym13061019.
[4] Soligo G, Roccon A, Soldati A. Coalescence of surfactant-laden drops by Phase Field Method. J Comput Phys 2019;376:1292–311. https://doi.org/10.1016/j.jcp.2018.10.021.
[5] Chang C-H, Franses EI. Adsorption dynamics of surfactants at the air/water interface: a critical review of mathematical models, data, and mechanisms. Colloids Surf Physicochem Eng Asp 1995;100:1–45. https://doi.org/10.1016/0927-7757(94)03061-4.
[6] Guido S, Simeone M. Binary collision of drops in simple shear flow by computer-assisted video optical microscopy. J Fluid Mech 1998;357:1–20. https://doi.org/10.1017/S0022112097007921.
[7] https://www.bilibili.com/video/BV1VL411W7YW/?spm_id_from=333.999.0.0&vd_source=74900a6270cea4f0a4628999154f84f8
