Abstract: Using air as gas working fluid and with liquids of different surface tensions （pure water，0.01% SDS solution，0.5% SDS solution，ethanol） as working fluids，a visualization experiment was conducted to study the split of annular flow through a T-junction with a rectangular cross section （100 μm×800 μm）. The results showed that the liquid preferentially enters the side branch. Liquid taken off mainly concentrated in 0.25—0.65 and gas taken off mainly concentrated in 0.1—0.8. The rate of increase of liquid taken off become bigger with increase of gas taken off. It was found that the liquid taken off of annular flow decreases with an increase of superficial liquid velocity at a certain superficial gas velocity. When the superficial liquid velocity is certain，there is very little effect of inlet gas flow rate on the liquid taken off. We also found that the decrease in liquid surface tension make the liquid taken off increase. When the present data were compared to those from other diameter junctions，it is seen that the phase split characteristics of the annular flow is very dependent on pipe size.

Key words: annular flow, micro-T-junction, phase splitting

摘要： 以氮气为气相工作介质，以不同表面张力的液体（纯水、0.01%SDS溶液、0.5%SDS溶液、乙醇）为液相工作介质，对矩形截面为100 μm×800 μm的T形微通道内的气液环状流进行了相分离可视化实验。实验结果表明：环状流液相在侧支管中采出占优势。液相采出分率主要集中在0.25～0.65之间；气相采出分率在0.1～0.8，液相采出分率的增长幅度随着气相采出分率增加而变大。当气相表观速度一定时，液相采出分率随着两相流液体速度的增加而降低；当液体表观速度一定时，气体速度变化对液相采出分率影响不大；当两相的表观速度一定时，液相采出分率随着液体的表面张力降低而减小。所得实验数据与其它尺寸的数据进行比较，发现管径尺寸对环状流相分离有较大影响。

关键词: 气液两相流, T形微通道, 相分离