Pressure Drop for Gas and Polymer Aqueous Solution Two-Phase Flows in Horizontal Circular Microchannel

Abstract

This study investigated pressure drop for gas and non-Newtonian liquid two-phase flows in a horizontal circular microchannel (0.25 mm I.D.) made of fused silica tube. Three kinds of polymer aqueous solutions (sodium carboxymethyl cellulose, xanthan gum and polyacrylamide) with different mass concentration were used as non-Newtonian liquids, while the nitrogen gas was used as the test gas. The flow conditions were varied in the range of the volumetric flux jL???=???0.12???0.58 m/s for the liquid phase and the volumetric flux jG???=???0.03???0.84 m/s for the gas phase. The flow patterns observed for these combinations of gas???liquid conditions were all slug flow or Taylor flow. In the preliminary experiment for single-phase liquid flows, Darcy friction factor data were obtained for non-Newtonian liquid as well as Newtonian one, and the obtained friction factor agreed with that for Hagen-Poiseuille flow by using generalized Reynolds number. The two-phase pressure drop varied depending on types of polymer because of the shear thinning effects of polymer solutions with the shear rate. In addition, the elasticity of polymer solutions depending on its molecular weight might affect the pressure drop characteristics. The experimental data of two-phase pressure drop have been compared with the result calculated by existing models. As the comparison results, the existing models predicted the present data if the appropriate correlations for homogeneous viscosity and two-phase friction multiplier needed in the models were used for each polymer aqueous solution. In addition, the unit cell model could correlate the pressure drop data if a fitting parameter changes against each polymer solution.