Basic Research for High Performance of High Pressure Contra-rotating Small Hydrotubine by Volute

Abstract

In order to develop an in-line small hydroturbine that can generate 300W at a small flow rate of 3l/s, we adopted a contra-rotating rotors to achieve both miniaturization and high efficiency of our hydroturbine in this study. A centrifugal rotor that can be applied to small flow rates and high heads is used for a front rotor, and a hybrid rotor that combines a mixed flow rotor and an axial flow rotor is used for the rear rotors with the propose of recovering the same head as the front rotor. In this study, a volute was employed to inject pre-swirl into the front rotor. In addition, the number of blades, exit angle, and rotation speed of the front rotor were changed, and numerical flow analysis was conducted to improve the performance of the front and rear rotors.