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以水为分散相、硅油为连续相,对高度为30μm、宽度800μm的T型垂直交错结构微通道中油包水型液滴的形成进行了实验研究。通过改变分散相和连续相流量配比,生成了大小可控的nL级液滴。对流量和液滴直径的关系以及流速、压力在液滴形成过程中的变化趋势进行了分析,得到黏性剪切力和界面张力是液滴形成的主要因素。发现流量较大时,两相在主通道内形成层流,并在微通道的台阶突扩处生成两种类型液滴。同时,在台阶突扩处液滴出现三种排列方式:交错双排Z字型、珍珠项链型和单排型液滴排列,并在低流速下出现液滴破碎现象,其发生主要取决于界面张力和流动阻力的影响。
Abstract：Droplet formation in a 30 μm high 800 μm wide microfluidic T-junction device was investigated experimentally using water as the dispersed phase and silicone oil as the continuous phase. The production of micron size droplets with a perfectly controllable diameter was affected by flow dynamics of both the dispersed and the continuous phase. Experimental results,including the relation between diameter and flow rates and the change of the velocity and pressure at drop break up process,were analyzed. As the conclusion,the break up is dominated by shear-stress force and surface tension force. For large relative flow rate,droplet breakup occurs in branched microchannel network by different mechanism with the two liquids flow in parallel along the shallow channel segment. Three droplet patterns,reverse droplet,pearl necklace,single droplet,are described in branched microchannel network. When the flow rate dropped down,the droplets were found to be broken,which depends on the change of surface tension force and the drag force of droplets.
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基本信息:
中图分类号:O359
引用信息:
[1]刘志鹏,徐进良.T型微流控芯片中的液滴形成[J].微纳电子技术,2007,No.358(03):137-141+158.
基金信息:
国家自然科学基金资助项目(50476088);; 广东省自然科学基金资助(5000729)
2007-03-15
2007-03-15