Experimental research on the correlations of holdup and frictional pressure drop in air-water two-phase flow in a capillary rectangular channel

In order to clarify the flow phenomena of gas-liquid two-phase flow in a capillary rectangular channel, the flow patterns, the passing frequency and the velocity of the liquid lump, the holdup and the frictional pressure drop in vertical upward and horizontal flow were investigated experimentally. The dimension of the channel used was 9.9 mm × 1.1 mm. The orientations of the channel were with the wide side vertical and the wide side horizontal. The differences between the flow characteristics in such orientations were investigated. The effects of the orientation of the duct, the aspect ratio of the cross section of the channel, superficial gas velocity and superficial liquid velocity on those two-phase flow parameters were examined. New correlations of holdup and frictional pressure drop for a capillary channel are proposed in which the effect of the aspect ratio, non-dimensional parameters such as Reynolds number and Capillary number and so on have been taken into consideration.