Numerical simulation of gas-liquid flow through a 90° duct bend with a gradual contraction pipe

Abstract

The effect of a gradual contraction pipe (GCP) on gas-liquid flow in a circular-sectioned horizontal to vertical 90° duct bend was investigated by computational fluid dynamics (CFD) simulation. The hydrodynamics of gas-liquid flow in 90° duct bends with and without a GCP in the vertical section were compared using a 3D steady Eulerian-Eulerian approach. The predicted static pressure in the vertical section of the pipes and the pressure drop in the whole pipe were consistent with experimental data. Results of simulations showed that liquid could distribute more uniformly at the exit of the pipe with a GCP. The increased uniformity was accompanied by an increase in pressure drop by a factor of less than 10% compared to the pipe without a GCP. The position of minimum pressure in the bend was changed by the GCP. A GCP can alter the trajectories of the fluid and secondary flow. As a result, the fluid can quickly reach a steady state downstream from the bend.