Performance study of a Helical Savonius hydrokinetic turbine with a new deflector system design

•This paper proposes a new deflector system around Helical Savonius rotor.•Six deflector system configurations had been studied numerically.•The deflector system affects the hydrodynamic characteristics of the flow.•The rotor power coefficient was found dependent on the deflection angle.•The power coefficient of the rotor reaches 0.14 using the optimal configuration. The use of renewable energy sources has becoming a necessity to generate electricity. Helical Savonius rotors have been preferred for small-scale hydropower generation. Numerous studies were carried out to improve the performance of the Helical Savonius rotor which has not been fully explored. In this paper, an experimental study was carried out to evaluate the performance of a Helical Savonius water rotor in an irrigation channel. In order to enhance the performance of the studied water rotor, a new deflector system design was proposed. Different configurations of the proposed deflector system were tested numerically using the commercial software ANSYS FLUENT 17.0. Without a deflector system, the maximum power coefficient is found to be equal to 0.125 at tip-speed ratio of 0.7. Using the optimal configuration of the new deflector system, the maximum power coefficient reaches 0.14. The utilization of this new design system is predicted to contribute towards a more efficient use of flows in rivers and channels for electricity production in rural areas.