Numerical Analysis and Model Evaluation on Flow and Heat Transfer Characteristics of LBE in a Pipe Based on DNS Data

Abstract The liquid lead-bismuth eutectic (LBE) considered as an alternative coolant for liquid metal-cooled fast reactors has the characteristics of high density and ultra-low Prandtl number (Pr) which produces significantly distinctive characteristics compared to ordinary coolants. Numerical simulation study on the flow and heat transfer characteristics in a straight pipe of length 12.5D with constant wall temperature and constant heat flux boundary conditions separately. With the condition of Reynolds number (Re) range of 5300∼37700, the comprehensive analysis based on calculated results was performed. The calculated results of axial velocity profiles, near-wall temperature and turbulent stress are compared with the data calculated by Direct Numerical Simulation (DNS) or Large Eddy Simulation (LES). By comparing multiple turbulence Prandtl number (Prt) models, this study aims to provide advice for the selection of turbulence models suitable for LBE. In addition, the study gives the most effective Prt model for specific conditions. It is noted that multiple Prt models demonstrate varying degrees of applicability for different boundary conditions. While the predictions on axial velocity remain consistent with different Prt models under above working conditions, the agreement on wall temperature compared with DNS or LES data varies.