Performance improvement of mixed-flow centrifugal pumps with new impeller shrouds: Numerical and experimental investigations

Abstract

Abstract A new impeller configuration with innovatively-designed shrouds is introduced, and its impact on the pressure head and efficiency of the semi-open centrifugal pump is explored using experimental and numerical approaches. The proposed design includes attaching specific plates called bladelets to a semi-open impeller to limit the secondary flows over the blades resulting in an increase in the pump head and efficiency. Hydraulic performance of a centrifugal pump with three different bladelets at angles of 30°, 60°, and 90° is investigated experimentally, and the results are compared to semi-open and closed impellers. The values of pressure head and efficiency of the proposed centrifugal pump are determined through numerical analysis and then compared to the experimental data in which an acceptable agreement between the results is observed. Both numerical and experimental results show the proposed impeller design promisingly improves the pressure head and efficiency of semi-open centrifugal pumps. Additionally, the flow analysis demonstrates that the impellers with 90° bladelets enhance the hydraulic performance of a semi-open centrifugal pump nearly to a closed impeller configuration. The loss reduction due to the secondary flow and the eddy generation leads to an improvement in the hydraulic performance of the proposed design.