双重乳液液滴在剪切流场中变形的数值模拟  

Simulation of double emulsion droplet deformation in shear flow

作　　者：左炀[1] 魏文韫[1] 余徽[1] 漆小波[2] 

机构地区：[1]四川大学化学工程学院,四川成都610065 [2]中国工程物理研究院激光聚变研究中心,四川绵阳621900

出　　处：《化学工程》2015年第5期68-72,78,共6页Chemical Engineering(China)

基　　金：中国工程物理研究院科学技术发展基金项目(2010A0302015;2011B0302058)

摘　　要：制备高质量的大尺度聚α-甲基苯乙烯微球是激光惯性约束聚变靶丸的关键技术之一。研究了以旋转蒸发的流场为基础,简化为套筒旋转生成典型的剪切流场所生成外水相流场条件下油相/内水相复合液滴的运动、变形特性。结果表明:乳液液滴的形变主要受黏性剪切力和表面张力的作用。在相同条件下,乳液液滴内部的变形程度要小于液滴整体的变形程度。在相同的剪切力条件下,复合液滴毛细数Cawh随界面表面张力的减小而增大,液滴的变形程度随着Cawh数的增大而加剧。因此,表面张力是微球维持球形度的主要动力。当增加剪切率使得Cawh和复合液滴雷诺数Rewh达到0.22时,液滴发生断裂。For an inertial confinement fusion （ICF）, the spherical target should be the high-quality large-scale poly-α-methylstyrene （PAMS） shells. The process of fluorobenzene removed by evaporation was simulated using computational fluid dynamics method. The effect of shear flow was examined to evaluate the interface movement. The results show that PAMS capsules are mainly affected by the viscous shear forces and surface tension effects. Under the same conditions, the extent of deformation of the inner droplet is less than that of the droplet as a whole. In the same shear force conditions, the capillary number of whole drop Cawh increases with the decrease of the interracial surface tension, and the degree of deformation of the droplet is aggravated with the increase of Cawh number. Thus, the surface tension is the main driving force of the capsules to maintain the spherical degree. The breakup of capsule occurs when increasing shear rate makes both Cawh and Reynolds number of whole drop Rewh reach 0.22.

关 键 词：双重乳液 聚-α-甲基苯乙烯 变形 毛细数 

分 类 号：O632.13[理学—高分子化学] TQ021.1[理学—化学]