Experimental and numerical simulation of erosion-corrosion of 90° steel elbow in shale gas pipeline

Coexistence of the solid particle erosion and acid liquid corrosion is common in shale gas gathering and transportation pipelines. It is conceivable that the synergistic effect of erosion and corrosion accelerates the pipeline damage process. In this research, a novel experimental device is designed to study the erosion-corrosion characteristics of 90° steel elbow in the gas-liquid-solid three-phase flow. A total of 28 group experiments are designed including 4 gas velocities, 3 liquid pH values, and 150 μm average sand particles. Moreover, a numerical simulation model is built based on the FLUENT code to predict the erosion-corrosion behavior. Experimental and simulation results show that the most severe erosion-corrosion region of the pipe bend occurs at the axial angle of the elbow between 20° and 50° and at the radial angle of the elbow between −45° and 45°. At the bottom of the elbow and the outer wall surface close to the outlet, the synergistic effect of erosion and corrosion accelerates the wear of the pipeline, but the opposite phenomenon exists at the position of the elbow with an axial angle of 50–70°.