Numerical study on influencing factors of accelerated erosion experiment based on the consideration of fluid-mass transfer

Abstract

An accelerated erosion test with improved experimental efficiency is required to study the critical properties of pipe erosion failure in a reactor effluent air cooler used for the hydrocracking process. In this study, a single 90° elbow was simulated numerically with the design of an L16 orthogonal table to discuss the influencing factors of grid refinement at the bend. An analysis of the length–diameter ratio L1/D revealed that when L1/D increases to more than 5, the change in wall shear stress at the inner bend wall is insignificant. The mass transfer coefficient of ferrous ion and the maximum shear stress τm were also utilized to describe the erosion rate, including electrochemical corrosion and hydrodynamics. The factor that influenced mass transfer coefficient most was inlet velocity. The regions with high mass transfer coefficient were located at R1 and R2, with R1 showing a higher risk of electrochemical corrosion than R2. Operating pressure played a critical role in the effect on τm, which presented a low inside/high outside trend. The region with high τm was located at R3, where a high breakage risk of erodent product films was observed.