Hydraulic Design of a 3 kW-Class Pump-turbine Model and Performance Investigation by CFD

Abstract

Small hydro is a valuable source of energy for remote area power generation. Pump-turbines are one of the most efficient ways to make and utilize the hydro energy. The purpose of the study is to design a pump-turbine model and conduct CFD analysis for performance prediction. The pump-turbine system is to be installed using an existing Francis turbine experiment model facility, so the overall casing and draft tube dimensions of the pump-turbine are the same as the existing Francis turbine. Only the dimensions of the stay vanes, guide vanes and impeller are different. Several impeller designs were investigated to match the design requirements of the model test facility. The performance and internal flow characteristics of the initial and final designs are compared and the best design is suggested for manufacturing for testing in the model test facility. The CFD results show relatively good results in both modes achieving more than 80% in hydraulic efficiency.