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.
