液液两相同轴流液桥断裂过程研究  

Study on the rupture of liquid bridges in liquid-liquid two-phase coaxial flow

作　　者：焦博亚 郭凯[1] 刘辉[1] 刘春江[1,2] 郑龙云 张雅楠 JIAO Boya;GUO Kai;LIU Hui;LIU Chunjiang;ZHENG Longyun;ZHANG Yanan(School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China;State Key Laboratory of Chemical Engineering(Tianjin University),Tianjin 300072,China)

机构地区：[1]天津大学化工学院,天津300072 [2]化学工程联合国家重点实验室(天津大学),天津300072

出　　处：《化学工业与工程》2024年第4期160-168,共9页Chemical Industry and Engineering

基　　金：国家自然科学基金项目(21706182,21706187)。

摘　　要：液液两相流中分散相在形成主液滴时会产生液桥,液桥断裂后在表面张力的作用下收缩为卫星液滴。卫星液滴的体积通常为主液滴体积的几千分之一,因此卫星液滴的出现会导致液滴的单一分散性变差。通过高速相机记录液桥形成及断裂过程,采用CFD方法计算液滴形成过程中速度场的变化。结果发现当两相黏度比越大时,液桥受到的剪切力越大,液桥的最大长度越小;分散相流量增大也会导致液桥受到的剪切力增大,液桥的最大长度减小。Droplet formation is often encountered in many industrial processes and it is widely used in petrochemical,fine chemical,energy,food,biological pharmaceutical,and environmental protection.Compared with the traditional batch production mode,continuous droplet production based on liquid-liq-uid two-phase flow has simpler operation and higher product benefit,which receives more attentions.In liquid-liquid two-phase flow,a liquid bridge is formed when the dispersed phase forms the main droplet,and the liquid bridge shrinks into satellite droplet after rupture due to the surface tension.The volume of satellite droplet is usually one thousandth of the main droplet,so that the appearance of satellite droplet will lead to poor single dispersion of the droplet.In this paper,the formation and rupture process of the liquid bridge as well as the factors influencing the maximum length of the liquid bridge are studied by ex-periment and CFD method.A device is built to record the generation of droplets in the liquid-liquid coax-ial flow using a high-speed camera.The liquid bridge formation and rupture process is recorded and the maximum liquid bridge length is obtained using the CFD calculation.The results show that the maximum length of the liquid bridge decreases when the capillary number increases.But the capillary number is not the only factor affecting the maximum length of the liquid bridge.It also related to the viscosity ratio of the two phases.When the viscosity ratio of the two phases increases,the shear force of the liquid bridge increases,while the maximum length of the liquid bridge decreases.The rupture process of the liquid bridge is closely related to the variation of velocity around the liquid bridge.

关 键 词：液液两相 同轴流 液桥 高速摄像 CFD 

分 类 号：TQ052.5[化学工程]