Multiphase Flow Mal-Distribution in Pipe Manifolds

A computational fluid dynamics (CFD) study was conducted on the mal-distribution problem occurring within pairs of spheroids used in the oil industry as three-phase gravity separators. The simulations were performed using the Euler-Euler multiphase model combined with the k-ε turbulence model. Several oil production scenarios under different input conditions of flow rates and temperatures were investigated. Flow regime maps were used to determine the likely multiphase flow nature upstream of the T-junctions employed within the spheroids pipe network as splitters. The simulation results confirmed the mal-distribution phenomenon and showed interesting details of the multiphase flow behavior inside the piping network considered. A mal-distribution between the risers of each spheroid was, also, noticed. The relatively large number of T-junctions used as well as the structure of the downstream piping network employed led to complex multiphase flow behavior. Increased concentration of liquid phase reminiscent of accumulation was noticed in some parts of the piping network acting as an obstacle for the gas stream. The mal-distribution generated was in the range 12–20%. The symmetry of the piping networks and the arrangement of the T-junctions was found to be a key parameter among the causes of the mal-distribution.