摘要
液滴微流控中芯片微通道的壁面润湿性是决定微滴生成的重要因素之一。为研究环烯烃共聚物芯片微通道表面润湿性对通道内微滴生成以及流体流动行为的影响,利用流体体积(volume of fluid,VOF)模型对聚焦流微通道中水和氟油两相流动行为进行数值模拟,并制备了接触角为30°、90°、120°梯度下的芯片微通道壁面开展实验研究,模拟与实验吻合良好。结果表明:在固定物性和结构参数下,壁面润湿性越弱,油包水微滴越容易形成,壁面的减阻特性随之增强,并且壁面的减阻特性导致90°比120°时微滴的生成频率低29.3%,直径增大8.3%;随着润湿性的增强,水相相对于氟油相的界面由凸变凹,30°时芯片生成微滴由油包水变成水包油;随着连续相毛细数(Ca)的升高,壁面润湿性对微滴生成的影响减小。
The wall wettability of chip microchannels in droplet microfluidic is one of the important factors that determine droplet generation.In order to study the influence of surface wettability of cycloolefin copolymer(COC)microchannels on droplet formation and fluid flow behavior,volume of fluid(VOF)model was used to simulate the flow behavior of water and fluorine oil in focused flow microchannels,and the microchannels with contact angles of 30°,90°and 120°were prepared for experimental study.The simulation results were in good agreement with the experimental results.The results show that under the fixed physical and structural parameters,the weaker the wettability of the wall is,the easier it is to form water-in-oil droplets,and the drag reduction characteristics of the wall will be enhanced.Moreover,the drag reduction characteristics of the wall will result in the droplet generation frequency being 29.3%lower and the diameter increasing by 8.3%at 90°than at 120°.With the increase of wettability,the interface between water phase and fluorine oil phase changes from convex to concave,and the droplets generated by chip change from water-in-oil to oil-in-water at 30°.With the increase of capillary number of continuous phase,the influence of wall wettability on droplet formation decreases.
作者
李洋
郑艳萍
梁帅
徐刚
LI Yang;ZHENG Yan-ping;LIANG Shuai;XU Gang(School of Mechanical and Power Engineering, Zhengzhou University, Zhengzhou 450001, China;Guangdong Shunde Innovative Design and Research Institute, Foshan 528311, China)
出处
《科学技术与工程》
北大核心
2021年第23期9799-9804,共6页
Science Technology and Engineering
基金
国家自然科学基金(U1833116)
河南省高等学校重点科研项目(20A460023)。
关键词
微流控芯片
VOF模型
壁面润湿性
毛细数
减阻特性
环烯烃共聚物
microfluidic chip
VOF model
wall wettability
capillary number
drag reduction characteristics
cycloolefin copolymer