“In the field of reactor engineering, narrow rectangular channels have outstanding heat transfer capabilities. As the fourth generation liquid metal reactor coolant, liquid lead bismuth alloy has significant differences in heat transfer characteristics compared to conventional fluids. This study used CFD software Fluent to numerically simulate turbulent flow in narrow rectangular channels, and analyzed the applicability of different turbulence models and turbulent Prandtl number models, providing a reference for accurately simulating turbulent heat transfer in liquid lead bismuth alloys.”