Liquid film characteristics of slug flow in a rectangular channel

In order to investigate the mechanism of slug flow, visualized experiments were conducted by using a high speed video camera system in a rectangular channel (3.25 mm×40 mm). It was found that the Taylor bubble length LT increases almost linearly with the increasing of gas phase Reynolds numbers ReG, while its increase rate decreases with the increasing of liquid phase Reynolds numbers ReL. The liquid film separating thickness δf decreases with increasing of ReGand approximates to constant when it varies inversely with ReL. The ReG and ReLas well as the LT have significant influence on δf. For LT≥150 mm, the δf approximates to constant. The liquid film separating velocity Vf increases with increasing of ReL. For low ReL, Vf is downward and decreases with increasing of ReG. When ReL≥ 9 102, the film always moves upward, the ReG has weak effect on Vf and Vf is mainly determined by ReL. The computational correlations of LT, δf and liquid film separating velocity relative to Taylor bubble Vfr are proposed according to data fitting, respectively. The correlations showed relatively good agreement with the experimental data.