共轴微通道内液滴生成的二维数值模拟分析  

Two-dimensional numerical simulation analysis of droplets generation in co-flowing microchannels

作　　者：叶文林 胡瑄 YE Wen-lin;HU Xuan(School of Mechanical and Electrical Engineering,Jingdezhen University,Jingdezhen 333000,Jiangxi Province,China)

机构地区：[1]景德镇学院机械电子工程学院,江西景德镇333000

出　　处：《化学工程》2023年第5期64-69,共6页Chemical Engineering(China)

基　　金：江西省教育厅科技项目(重点项目)基金资助项目(GJJ212804);江西省教育厅教改项目基金资助项目(JXJG-21-21-5)。

摘　　要：为探究材料参数和操作参数对共轴微流控装置内液滴生成特性的影响,建立适用于液液两相流模拟的计算模型,并采用VOF法进行数值求解。模拟过程中通过改变两相不同流率、两相梯度黏性和表面张力对液滴尺寸及伴随液滴生成的机制进行分析。通过分析发现:在外流场中,随着连续相流速的增大,生成液滴的直径会相应的减小;离散相流率变化会引起毛细管后液线长度发生变化,进而引起流态之间的转化,更重要的是会直接导致液滴尺寸发生改变,但离散相黏度对液滴直径的影响甚微;在相同流场变量下,换用表面张力更小的离散相后,发现生成的液滴直径也变小;最后,调整毛细管和外部通道的尺寸,发现液滴生成率和液滴直径的变化规律与调整前是一致的。In order to explore the influence of material parameters and operating parameters on the droplet generation characteristics in the co-flowing microfluidic device,a computational model suitable for liquid-liquid two-phase flow simulation was established,and the VOF method was used to solve the numerical solution.During the simulation,the droplet size and the satellite droplet generation mechanism were analyzed by changing the different flow rates of the two phases,the gradient viscosity and the surface tension of the two phases.Through the analysis,it is found that in the external flow field,with the increase of the continuous phase flow rate,the diameter of the generated droplets decrease accordingly.The change of the discrete phase flow rate causes the change of the length of the liquid line after the capillary,which leads to the transformation between the flow states,and more importantly,directly leads to the change of the droplet size,but the discrete phase viscosity has little effect on the droplet diameter.Under the same flow field variables,when the discrete phase with smaller surface tension is used,the diameter of the generated droplets also becomes smaller.Finally,after adjusting the size of the capillary and the external channel,the variation law of droplet generation rate and droplet diameter is consistent with that before adjustment.

关 键 词：多相流 均一液滴 共流流体 液滴脱离 数值模拟 

分 类 号：TQ02[化学工程]