Visualization of Gas-Liquid Interface of Annular Two-Phase Flow and Investigation on Mechanism of Liquid Droplet Entrainment

采用多壁电导探头(MWCP)和多点电极探头(MPEP)研究了气液两相流界面上产生的各种波的时空特征。利用工业孔径显微镜实现了环状两相流气液界面的可视化，并对液滴携带机理进行了研究。得到的结果如下：(1)MPEP得到的直径截面上的气液界面轮廓清晰地显示了段塞流向环状流的过渡流动状态。并阐明了过渡区复杂的气液界面结构。(2)利用MWCP测量技术给出了界面波的时空特征。从持液率轨迹的时空图可以很容易地计算出波速，并在该图上显示了波的生长和衰减。(3)工业孔径显微镜对于环空流气液界面的可视化是有效的。通过视频图像观察了界面波和夹带液滴的三维结构。

Multiple wall electric conductance probes (MWCP) and multiple point electrode probes (MPEP) were employed to investigate the time-spacial characteristics of various waves generated at gas-liquid interface of two-phase flow. Visualization of gas-liquid interface of annular two-phase flow was realized by an industrial bore scope and mechanisms of liquid droplet entrainment was studied. The results obtained are as follows.(1)Gas-liquid interdace profiles at an diametrical cross section obtained by MPEP clearly show the transition flow condition from the slug to annular flows. Complicated structures of gas-liquid interface in the transition region are also clarified.(2)Time-spacial characteristics of interfacial waves were presented by the MWCP measurement technique. Wave velocities are easily calculated from the time-spacial map of liquid holdup traces, and growth and decay of wave are shown in this map.(3)Industrial bore scope was valid for visualization of gas-liquid interface of annular flow. Three dimensional structures of interfacial waves and entrained liquid droplets were observed by video pictures.