A lattice Boltzmann modeling of corrosion behavior and oxygen transport in the natural convection lead-alloy flow

Corrosion of structural materials presents a critical challenge in the use of lead–bismuth eutectic (LBE) or liquid lead as a nuclear coolant in accelerator-driven systems and advanced reactors. Actively controlling the oxygen concentration in LBE has been proved to be effective to mitigate corrosion under certain conditions. For mixing the oxygen uniformly and quickly, natural convection is proposed to enhance the oxygen transport. In the present study, a lattice Boltzmman simulation of coupled natural convection and lead bismuth eutectic flow in a simplified container was carried out to study characteristics of the oxygen transport and corrosion behaviors. It is assumed that the corrosion product (mainly iron) concentration is at its equilibrium level at the wall. The wall boundary condition for the mass transfer of corrosion production was taken based on the active-oxygen-control model. To examine the effect of different nature convection flow patterns on corrosion behavior and oxygen transport, three heating cases, which correspond to one-, two- and four-vortex flow patterns, are examined. Both of the local and average Sherwood number at the wall, distribution of corrosion product and oxygen, and oxygen diffusion time are analyzed. Some useful information was obtained to understand the mechanism of corrosion behavior and oxygen transport in the LBE system.