Comparison of Performance Improvement on Impeller Round Tip and Flat Tip for Pump as Turbine
A reverse running centrifugal pump is one of the attractive choices in micro-hydropower development and
industrial pressure energy recovery. Pumps as turbines have been successfully applied in a wide range of small hydro sites in
the world. Since the overall efficiency of these machines is lower than the conventional turbines, their application in larger
hydro sites is not economical. Therefore, the efficiency improvement of reverse pumps is essential. In this study, by focusing
on a pump impeller, the shape of blades was redesigned to reach a higher efficiency in turbine mode by modification in
impeller tip. Modification was done by rounding the blade on impeller tip. After each modification, a new impeller was
manufactured and tested in the test rig. The objective of this paper is to improve the efficiency of PAT by modification on
impeller tip. In this paper, 3-D numerical CFD tool for simulation of the flow field characteristics inside the pump as turbine
are analyzed and simulated by using Flow Simulation in ANSYS Workbench 17.0. According to the experimental and
numerical result, the efficiency of impeller round tip is greater than flat tip.
Keywords- Modification, Impeller Tip, Efficiency, Blade Rounding.