Numerical Simulation of Turbulent Flow in Carbon Steel Pipes Leading to Flow Accelerated Corrosion

In the present study, turbulent flow fields in diverse carbon steel pipe components leading to flow accelerated corrosion (FAC) are analyzed using the Realizable turbulence model. The present study is inspired by the detailed case studies of flow accelerated corrosion in nuclear power plants around the globe. The Numerical study is conducted with the main objective of analyzing the flow around the recirculation regions arising in different piping components, such as sudden expansion, double elbow, orifice and T-bend, since these components are known to be more susceptible to FAC. Employed Realizable k-ε turbulence model and the flow simulations are validated with the Experimental and Numerical results available in the literature. The topological consistency is verified by means of a topological invariance relation of the flow based on the Euler number. The calculated reattachment length increased, but the concentration of ferrous ions decreased or remained almost constant at the corner recirculation regions as a function of Reynolds number. As the shear stress distribution is one of the most important factors in predicting the local regions of pipes that are highly susceptible to FAC, this distribution was calculated in the considered geometries. These results would help to select the components that are more susceptible to FAC. In addition, the locations of the maximum wall shear stress are identified in each component. It is observed that the double elbow and orifice are two components that are more susceptible to FAC among all the considered components.