Numerical study of the hydrodynamic parameters influencing internal corrosion in pipelines for different elbow flow configurations

Oil-water two-phase flow is common in the ocean engineering, petroleum, and chemical industries, among others. In the transportation process, the elbow system - as a paramount component - usually suffers from internal corrosion. In order to investigate the corrosion-prone characteristics of elbow systems, the volume of fluid (VOF) method and the renormalization group (RNG) k-epsilon model were used to study the oil-water flow in three different elbow configurations. The results indicate that the maximum wall shear stress and mass transfer coefficient are located at the intrados of the elbow for all flow configurations. Nevertheless, for horizontal-upward and horizontal-horizontal elbow flows, water does not come into direct contact with the intrados of the elbow, meaning it is much less susceptible to corrosion. Thus, a multiparameter model which also takes into account the water-volume fraction is necessary for characterizing the corrosion process. When this was combined with an analysis of the water wetting process, the horizontal-downward elbow flow was found to exhibit the largest corrosion risk among the three configurations examined, the horizontal-upward elbow flow was the least susceptible and the horizontal-horizontal elbow flow was in the middle.