A CFD SSTk−ω−kθ−εθ four parameter heat transfer turbulence model for the 19-pin fuel assembly in LBE cooled reactors

Abstract

Liquid lead-bismuth eutectic (LBE) alloy exhibits excellent thermo-hydraulic properties and chemical inertness as a coolant for fast reactors. Unlike conventional fluids such as water and air, LBE has a lower Prandtl number ($\mathrm{Pr}$), and its local turbulent Prandtl number (${\mathrm{Pr}}_t$) is nonlinear. Therefore, the constant turbulent Prandtl number is difficult to satisfy complex turbulent heat transfer calculations. Thus, developing a high-precision $k_{\theta }-{\epsilon }_{\theta }$ two parameter turbulent heat transfer model for lead bismuth alloys has significant engineering value. This study systematically derives the $SSTk-\omega -k_{\theta }-{\epsilon }_{\theta }$ four parameter turbulence heat transfer model and its boundary conditions under constant heat flux boundary. Based on the open source CFD software OpenFOAM, a four parameter heat transfer turbulence solver named LBEHMTFoam is developed to enhance the prediction accuracy of turbulent heat and mass transfer in liquid lead-bismuth alloys. The accuracy of the model is validated by comparing the simulation results of planar flow heat transfer with direct numerical simulation (DNS) data. Furthermore, heat and mass transfer simulations are conducted for LBE fuel assemblies and compared with empirical correlations. This study provides an effective tool for accurately predicting the thermo-hydraulic coupled corrosion behavior in LBE systems and holds significant reference value.