Revista de Ciências e Engenharia de Materiais

Design Optimization and CFD and Performance Analyses of Miniature Axial-Centrifugal Flow Pumps for Circulating Molten Lead

Abstract

Mohamed S. El-Genk*, Timothy M. Schreiner and Andrew S. Hahn

For circulating molten lead in compact in-pile and ex-pile test loops at 773.15 K this work developed a multi-physics methodology to optimize the designs of miniature axial-centrifugal flow pumps with impeller blades diameters of 55.0, 60.0 and 66.8 mm for maximizing the pumping power, the pump efficiency, and the pressure head. Increasing the diameter of the optimized impeller blades and/or the shaft rotation speed from 1,500 to 3,000 RPM increases the pump characteristics and efficiency, but also increases the dissipated thermal power. The molten lead flow rate at the peak efficiency increases with increased impeller shaft rotation speed and /or the blades outer diameter. The performed CFD analysis shows that rounding the tips of the blades and/or decreasing their clearance from 1.5 to 2.0 mm limit the formation of the flow vortices and the pressure losses and increases the pump efficiency. Results also show that increasing the molten lead temperature from 673.15 to 873.13 K slightly decreases the pump pressure head and negligibly affects the pump efficiency. This work successfully demonstrated the use of additive manufacturing of an impeller design with 60.0 mm diameter blades.