基于插入毛细管的改进T形微通道液滴生成特性研究
Research on Droplets Formation Characteristics of Modified T-Junction Microchannel Based on Inserted Capillary
申峰 1李春游 1代建峰 1刘赵淼1
作者信息
摘要
本文提出了一种基于插入毛细管的改进T形微流控芯片装置,并利用显微高速摄影开展了液滴(气泡)生成流动可视化试验,研究了毛细管插入深度、两相流量对液滴生成特性的影响,得到了液滴生成过程中界面演化的动态全过程.与气泡生成过程进行对比研究,揭示了液滴受力及断裂的流体力学机理.结果表明,此芯片装置可以稳定地生成尺寸可控的微液滴(气泡),且两相流量比的范围较宽(2～12);液滴生成方式仅为液滴模式,液滴生成过程中先后经历了液滴头部生成、头部填充和颈缩断裂三个阶段,这是由连续相的压力、黏性剪切力和界面张力共同作用的结果;增加连续相流量(100～600μL/min)或增加毛细管插入深度(0～120μm),液滴生成尺寸减小(630～201μm)、频率增加;液滴颈部有挤压断裂和剪切断裂两种模式.研究结果可以为液滴微流控芯片结构设计及应用提供理论指导.
Abstract
A modified T-junction microfluidic chip device based on inserted capillary was proposed,and the flow visualization experiments of droplets(or bubbles)generation were carried out using micro high-speed photography.The effects of capillary insertion depth and two-phase flow rates on droplet generation characteristics were investigated,and the dynamic process of interface evolution during the droplets generation was obtained and compared with that of bubbles.The hydrodynamic mechanism of droplet stresses and fracture was revealed.The results show that this chip device can generate micro-droplets(bubbles)of controlled sizes stably,and the range of two-phase flow rate ratio are wide(2～12).The droplet generation mode is only droplet mode,and the droplet formation process experiences three stages,namely droplet head generation,head filling and necking fracture.This process is the result of the combined effects of the fluid pressure,viscous shear force and interfacial tension.Increasing the continuous phase flow rate(100～600μL/min)or increasing the capillary insertion depth(0～120μm),the generated droplet size decreases(630～201μm)and the frequency increases.There are two modes of droplet neck fracture,namely extrusion and shear.The results could provide theoretical guidance for the design and applications of droplet microfluidic chips.
关键词
微流控技术/液滴生成/气泡/插入毛细管/T形微通道Key words
microfluidics/droplet formation/bubble/inserted capillary/T-junction microchannel引用本文复制引用
出版年
2024
NETL
NSTL
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