Abstract

An urgent problem at the moment is to study various microchannel systems owing to the trend of miniaturization of devices. The present study is aimed at investigating the properties of the working liquid on the regimes of a two-phase flow and pressure drop in a flat microchannel 130 \(\mu\)m high. The high-speed schlieren method is used for visualization of fast processes that occur in the microchannel. It is shown that the working liquid properties and microchannel wall wettability produce a significant effect on the two-phase flow regimes and transitions between them. Regions of jet, bubble, and churn flow regimes are observed at identical Weber numbers of the liquid and gas for different working liquids. The hydraulic resistance of various working liquids is studied. It is demonstrated that drastic jumps with an increase in the superficial gas velocity are observed for water during the transition to the churn flow regime. This feature is associated with washout of dry spots with an increase in the superficial liquid velocity owing to a significant effect of the hysteresis of the contact angle of wetting.

中文翻译：

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扁平微通道中液体性质对气液流动规律和压降的影响

摘要

由于器件小型化的趋势，目前一个紧迫的问题是研究各种微通道系统。本研究旨在研究工作液体在扁平微通道 130  \(\mu\)米高。高速纹影方法用于可视化发生在微通道中的快速过程。结果表明，工作液体性质和微通道壁润湿性对两相流态及其之间的转变产生显着影响。对于不同的工作液体，在液体和气体的相同韦伯数下观察到射流、气泡和搅动流态区域。研究了各种工作液体的水力阻力。结果表明，在过渡到搅动流态期间，观察到水的表观气速增加的剧烈跳跃。由于润湿接触角滞后的显着影响，该特征与干点的冲刷以及表面液体速度的增加有关。