Prediction of oil-water flow patterns, radial distribution of volume fraction, pressure and velocity during separated flows in horizontal pipe

Abstract

Flow of two immiscible fluids gives rise to variety of flow patterns, which influence transportation process. In this work, we present detailed analysis on the prediction of flow pattern maps and radial distribution of volume fraction, pressure and velocity of a pair of immiscible liquids through a horizontal pipeline by computational fluid dynamics (CFD) simulation using ANSYS FLUENT 6.3. Moderately viscous oil and water have been taken as the fluid pair for study. Volume of fluid (VOF) method has been employed to predict various flow patterns by assuming unsteady flow, immiscible liquid pair, constant liquid properties, and co-axial flow. From the grid independent study, we have selected 47 037 number of quadrilateral mesh elements for the entire geometry. Simulation successfully predicts almost all the flow patterns (viz., plug, slug, stratified wavy, stratified mixed and annular), except dispersion of oil in water and dispersion of water in oil. The simulated results are validated with experimental results of oil volume fraction and flow pattern map. Radial distribution of volume fraction, pressure and velocity profiles describe the nature of the stratified wavy, stratified mixed and annular flow pattern. These profiles help to developing the phenomenological correlations of interfacial characteristics in two-phase flow.