Comparison of pressure drop, lateral secondary flow, temperature, and convective heat transfer coefficients between traditional and new model fuel assemblies

To enhance the heat transfer capacity of the coolant, the arrangement and rotation direction of the winding wires in the lead based fast reactor fuel assembly were optimized, and a new mode fuel assembly was designed. This study conducted precise calculations on the rod bundle segments of traditional and new fuel assemblies based on the open-source CFD platform OpenFOAM. The calculation results show that compared with the traditional mode, the new mode has a smaller pressure drop along the fuel assembly rod bundle section, which is beneficial for reducing the pump head and sensor range; The new pattern design can enhance the mixing effect of coolant in the microchannel; The new mode design makes the temperature distribution of the coolant in the sub channel more uniform, and the temperature gradient at the component outlet smaller, which is conducive to reducing the thermal fatigue and creep of the reactor components near the component outlet. The new design mode improves the comprehensive heat transfer performance of fuel components.