Abstract: In view of the problems existing in the research of fluid-carrying pipeline failure, the mechanism of effect of interaction of corrosion and fluid flow on the erosion damage of pipeline is researched. The mathematical model of fluid-structure interaction is established. The N-S equation of viscous fluid under the description of arbitrary Lagrange-Euler (ALE) and the control equation of solid area of protective film of corrosion products are derived. The interaction between multiphase medium flow on the pipe wall boundary layer and the damage of protective film of corrosion products are analyzed. The erosion failure of elbow is taken as an example, by combining the structure characteristic of elbow and the physical parameters of multiphase flow, and by using finite element analysis software ANSYS and physical environment sequential coupling method, the numerical simulation of fluid-structure interaction is carried out, the deformation degree and stress state of the protective film of corrosion products on pipe wall are analyzed, the area vulnerable to erosion damage and the failure trend of elbow are determined. The on-site thickness measurement data are basically in agreement with the result of simulation calculation, thus verifying the reliability and feasibility of the simulation calculation. This method can be used in risk prediction, security evaluation and technological transformation of pipeline transportation system.

Key words: Elbow, Erosion prediction, Fluid-structure interaction, Numerical simulation, Protective film of corrosion product