Abstract: Liquid metal reactor is one of the main types of the Gen-Ⅳ nuclear power system. However, because the thermal properties of liquid lead-bismuth are very different from those of traditional working media such as water and air, the Reynolds analogy principle, which assumes that the flow boundary layer is similar to the thermal boundary layer, is no longer suitable. In this paper, a custom solver based on k-ε-k_θ-ε_θ four-parameter model was developed in open source program OpenFOAM. The difference between the thermal boundary layer and the flow boundary layer was considered. The flow heat transfer simulation of liquid lead-bismuth in a wire-wrapped rod bundle was carried out. The three-dimensional distribution of some important thermal hydraulic parameters such as velocity and temperature was obtained. The influence of wire on the flow and heat transfer process of coolant was revealed, and the calculated results were compared with the classical experimental correlations. The results are in good agreement, which indicates the correctness of the model and program. This study may provide references for CFD simulations of liquid metals flow and heat transfer by adding new models and developing custom solvers in OpenFOAM.