Numerical methodology to determine fluid flow pattern with corrosion in pipe bends using computational fluid dynamics software

Abstract

Flow-accelerated corrosion (FAC) is the most common failure in production and processing industries and nuclear power plants. The simulations were performed using Computational Fluid Dynamic (CFD) simulations of the flow in elbows of the Flow Accelerated Corrosion (FAC) test loop and using the FLUENT commercial software. The model geometry and mesh were created using the ANSYS FLUENT 14.0. The objective is to establish the relationship between the fluid flow patterns and corrosion behaviour within the pipe bend. The paper presented the results of the simulations of the flow in form of velocity vectors for two types of pipe bend, both mitred bend and smooth bend with three different Reynolds numbers 37387, 49850 and 62313 respectively. From the results obtained, it was observed that the mitre bend produces more wall shear stress, turbulent intensity and turbulent kinetic energy compared to the smooth bend and thus predicted to produce more corrosion However, with realizable k-ε model, more significant differences are evident when compared with RNG k-ε model and standard k-ε turbulence model. The maximums in both turbulent intensity, wall shear stress as well as turbulent kinetic energy now appear on the outer radius, near the elbow exit. Also, the simulation is used to obtain the FAC rate of the various elbows. The result shows that the FAC rate of the outward bend of the elbow is twoorders than the inward bend of the elbows