几何构型对流动聚焦生成微液滴的影响

发布时间：2018-04-21 07:41

本文选题：十字形微通道 + 流动聚焦　；参考：《力学学报》2016年04期

【摘要】：流动聚焦型微流控装置能够方便、高效地生成均一度好且大小精确可调的微液滴(气泡),故被广泛应用于颗粒材料合成、药物封装、细胞培养等诸多领域.进一步优化通道结构有助于实现对合成微粒粒径、均一度和尺寸范围的精确调控.本文数值研究了通道深度、缩颈段长度以及两相夹角等几何构型因素对流动聚焦生成微液滴直径及其生成周期各个阶段的影响.控制液滴生成方式为滴流式,发现液滴直径随通道深度d的增加近似呈线性增大,且当通道深度小于30μm时,随着通道深度的下降,微液滴生成周期在毛细力的强烈作用下出现骤升,通道深度超过80μm时,微液滴的生成周期基本接近恒定.连续相和离散相的夹角θ接近90?时,液滴直径及其生成周期最短,夹角太大或太小均不利于生成均一度好且粒径微小可控的液滴.调整缩颈段长度l引起液滴直径及其生成周期的变化幅度仅为其平均值的3%～5%左右.此外,缩颈段宽度也是影响流动聚焦生成微液滴直径及其生成周期的重要因素,在通道深度固定时,缩颈段越宽,微液滴直径及其生成周期越大.
[Abstract]:The flow focusing microfluidic device is convenient and efficient to generate microdroplets (bubble), which have been widely used in the synthesis of granular materials, drug encapsulation, cell culture and many other fields such as particle material synthesis, drug encapsulation, cell culture and so on. Further optimization of the channel structure is helpful for the precise control of particle size, homogeneity and size range. In this paper, the effects of geometric configuration such as channel depth, necking length and angle between two phases on the diameter of microdroplet and the formation period of microdroplet are studied numerically. The droplet formation is controlled by droplet flow. It is found that the droplet diameter increases linearly with the increase of channel depth d, and decreases with channel depth when the channel depth is less than 30 渭 m. The formation period of microdroplets rises suddenly under the strong action of capillary force. When the channel depth exceeds 80 渭 m, the formation period of microdroplets is almost constant. The angle 胃 between continuous phase and discrete phase is close to 90? The droplet diameter and its generation period are the shortest, and the large or too small angle is not conducive to the formation of droplets with small and controllable diameters. The change of droplet diameter and its forming period caused by adjusting the length of necking section l is only about 3% of its average value. In addition, the width of neck-shrinking segment is also an important factor affecting the diameter and formation period of droplets generated by flow focusing. When the channel depth is fixed, the wider the necking segment is, the larger the diameter of microdroplet and the period of formation are.
【作者单位】：北京工业大学机械工程与应用电子技术学院;
【基金】：国家自然科学基金资助项目(11572013)
【分类号】：O35

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