Hydrodynamic studies of 3D-Multiphase Flow of Gas-LiquidLiquid Three-Phase Flow in a Pipe at Two Different Bend Angles and their Resultant Pressure Drops.

Abstract

The phenomenon of flow of different phases flowing simultaneously in the pipelines of Petrochemical industries is of great interest. Different types of fittings and bends are used to connect these pipelines for transporting the fluids. The phenomenon becomes more complicated when more than two phases are flowing through it. Various flow patterns arise in the pipelines depending upon the individual superficial velocities of the phases and the type of bend. The radius to diameter (R/d) ratio, internal pipe’s diameter, flow orientation, and inclination of the pipe have significant impacts on flow behavior. Bend offers restrictions which results in loss of pressure. The restriction, hydrostatic, and frictional losses lead to combined pressure losses within pipelines. The Computational Fluid Dynamics (CFD) software is a highly demanding tool that proves to be very impressive in examining fluid behavior, its characteristics, and fluid pressure drops. Simulating the multiphase flows can save the material setup experimental cost and human time to conduct the long hours of experiments. This study emphasizes the use of CFD software to analyze the pressure drop and flow patterns within the 90°and 180°bend pipes and compares them with the experimental work. The three-dimensional (3D) geometries of 90° and 180° bend pipes having 6 inches internal diameter and R/d ratio of 1 are used. Superficial velocities of the liquid, oil, and gas were in the limit of 0.08- 0.36, 0.08-0.36, and 0.5-4 ms-1 respectively. The CFD simulation results from pressure drops of a 90° bend pipe with a steady 0.5 oil-to-liquid volume ratio (fo) value and increasing gas and oil velocities, at two fo values of 0.25 and 0.75, and maintaining a steady 0.32 ms-1 liquid velocity with increasing gas velocities, and at increasing fo values from 0.2-0.8, maintaining at 0.4 ms-1 liquid velocities with increasing gas velocities are compared with experimental work and have a maximum percentage error of 10.37%, 12.63%, and 9.03% respectively. Rolling wave pseudo-slug and slug flow patterns are three-phase flow patterns that were found at the 90° bend; these flow patterns were compared to experimental studies and demonstrated strong agreement. The pressure drops and the same flow patterns of the three-phase flow system were also analyzed in the 180° bend pipe.