The high-temperature liquid lead-bismuth metal has a scouring and wear effect on the head of the axial flow lead-bismuth pump impeller blades in a lead-cooled fast reactor system, causing the protective layer on the blade surface to break down and material corrosion rate to accelerate.

This study aims to reduce the scouring wear effect of the high temperature liquid metals on blade surfaces.

First of all, three types of leaf top clearance structures, i.e., plane, chamfered right angle, and chamfered rounded angle, were designed. Then, the reliability of the simulation results was verified by the scaling conversion method, and the commercial CFD software ANSYS CFX with SST k-ω turbulence model was employed to analyze the variation of flow velocity, shear force, and flow pattern with scouring and wear characteristics under different leaf top clearance structures. Finally, the energy loss of the high temperature liquid lead-bismuth metal on the material surface was analyzed using the wall entropy yield.

Analysis results show that the head and efficiency of the chamfered right angle model are reduced by 1.02% and 0.64%, respectively, compared with those of the flat surface under standard operating conditions, and the chamfered angle model shows a 0.51% reduction in the head and 0.51% efficiency increase. The impeller scouring wear effect occurs predominantly near the inlet edge of the blade rim, and the effect of the high temperature liquid metal on the blade head scouring wear is improved by the chamfered and rounded designs.

The chamfered and rounded designs reduces the mechanical energy loss on the blade surface by reducing the flow velocity at the top clearance and reducing the scouring wear effect at this location. Therefore, the rounded design and the right angle design could improve the influence of high-temperature liquid lead-bismuth metal on the erosion wear of the blade head.