Numerical Simulations of Wall Mass Transfer for Flow-Accelerated Corrosion (FAC) Applications

Flow-Accelerated Corrosion, FAC, is one of the most prevalent forms of degradation of carbon and low alloy steel pipes exposed to water flow, leading to significant wall thinning, especially in the secondary coolant systems of nuclear power plants. It is of critical importance to be able to predict regions of local FAC enhancement to avoid any future failure of the pipe systems. CFD alongside experimentations is a relevant tool to determine those locations of severe attack. This work compares the performance of High-Reynolds Number (based on large mesh) and Low-Reynolds number (based on thin mesh) turbulence models on the prediction of wall mass transfer in a turbulent pipe flow. It was shown here that High-Reynolds Number turbulence models were in good agreement with empirical correlations and literature data in a large range of Schmidt numbers (Sc). For Low-Re Number turbulence models, while reasonable predictions were found at low and moderate Schmidt, discrepancies emerged for high Schmidt values which may be due to inaccuracies in computing the turbulent viscosity and turbulent diffusivity in the wall vicinity.