Air–Water Two-Phase Frictional Pressure Drop in Minichannels

Abstract

This article presents the results of experiential investigations of frictional pressure drop in horizontal minichannels. An air–water mixture was used as the working fluid. The test section was made from stainless-steel pipes with internal diameters of 1.05, 1.35, 1.68, and 2.30 mm. Investigations were carried out at mass flux of 170–7350 kg/m2-s and gas quality from 0.001 to 0.22. Superficial velocity ranges of water and air were 0.2–7.4 m/s and 1.7–41.8 m/s, respectively. The results of experimental investigations were compared with theoretical values obtained from a homogeneous equilibrium model. The dynamic viscosity coefficient was calculated using dependences proposed by Owens, McAdams, Ackers, Cicchitti, Dukler, Beattie and Whalley, and Lin. It is found that none of the tested correlations can predict the two-phase pressure drop gradient satisfactorily. The homogeneous model with a correction factor proposed by Chen to use in minichannels was also used. In this case, the results of calculations were worst without consideration of which correlation was used to determine the dynamic viscosity coefficient.