Abstract:

Aiming at the complexity of the traditional flow confocal method in the two-phase flow injection and the large external packaging volume, this paper studies the related technology of micro-droplet generation in capillary tubes. With the commercial T-tube, a droplet generation method based on T-shaped cocurrent focusing structure is proposed. This method not only simplifies the injection structure of two-phase flow, but also solves the problem of difficult packaging, and is convenient for the further research on the relevant parameters of the droplet generation. For the relevant parameters of droplet formation, this paper deeply studies the relationship among droplet size, flow rate ratio and generation frequency in droplet formation. The influences of flow rate ratio, outlet cone angle and outlet diameter on the uniformity of the droplets are studied by orthogonal test. The order of the influence is: cone angle＞flow rate ratio＞outlet tube diameter. Under the condition of the optimal parameter: cone angle of 4°, the flow rate ratio of 190∶1, and the outlet pipe diameter of 72μm, the average volume of the generated droplets is 8.3nL, the generation frequency is 0.7Hz, and the uniformity is 0.011.

Key words: flow confocal, droplet generation, T-shaped cocurrent focusing, droplet uniformity

摘要：

针对传统流动共聚焦法两相流注入结构复杂，外部封装体积大的问题，本文开展了毛细管中微液滴生成的相关技术研究，借助商品化T形管，提出了一种基于T形共流聚焦结构的液滴生成方法。该方法不但简化了两相流的注入结构，较好地解决了封装难的问题，而且便于对液滴生成的相关参数开展进一步研究。对于液滴生成的相关参数，本文深入研究了液滴生成中液滴尺寸、流速比和生成频率之间的关系；通过正交试验深入研究了流速比、出口锥角角度和出口管径对液滴均一性的影响，其影响的主次顺序为：锥角角度＞流速比＞出口管径，在最优参数锥角角度为4°，流速比190∶1，出口管径72μm的条件下，所生成液滴平均体积为8.3nL，生成频率0.7Hz，均一性0.011。

关键词: 流动共聚焦, 液滴生成, T形共流聚焦, 液滴均一性