Visualization Study of Air-Water Two-Phase Flow Pattern in Upward Vertical Flow of Square Channel

An important two-phase flow experiment study is carried out as a consideration in the application of piping system design that depends on two-phase flow. The purpose of this study was to determine the air-water flow pattern formed in a small square channel with vertical flow direction and to know the flow configuration. Channel 5 mm hydraulic diameter was used in this study. Bubble, slug, churn, and annular flow patterns are formed in the air superficial velocity range 0.33 - 7.31 m/s and superficial velocity of water is 0.13 - 1.2 m/s. A flow pattern map produced has not similarities with the mini-channel flow pattern map in previous studies. The velocity of bubbles and void fractions increases with the increase of superficial air velocity. The void fraction of present research has a good correlation to the results of predictions proposed by previous studies. (paper)