Experimental studies on two-phase flow patterns aboard the Mir space station

A series of experiments on two-phase gas-liquid flow patterns in a test tub e with a length of 356 mm and an inside diameter of 10 mm were performed ab oard the Mir Space Station in August 1999. Carbogal and air were used as th e liquid and the gas phase, respectively. In the present paper, the experim ental results at the background microgravity environment of the Mir Space S tation (no more than 10(-5)g) were reported. Five kinds of flow patterns, n amely dispersed bubble flow, bubble flow, slug flow, slug-annular transitio nal flow, and annular flow, were observed in the space experiment. Due to t he small length-to-diameter ratio of the test tube used in the present stud y, the observed flow patterns should be considered to be developing ones. T he experimental results were compared with the model proposed previously wh ich accounts for the entrance effects on the flow pattern transitions. A go od agreement between the predictions and the experimental data was obtained . Some widely used models developed based on the analysis of fully develope d two-phase flow at microgravity were also compared with the present data i n order to make evaluations of these models and to have some insights on th e flow evolution. (C) 2001 Elsevier Science Ltd. All rights reserved.