Performance improvement of a novel combined water turbine

Abstract

Nowadays, industrials and researchers are looking for renewable energy resources due to the increase of energy demand. Recently, the ability of combined turbines in harnessing energy from water current has increased their renewed interest. However, there still exist a big knowledge gap to select the optimal design of these turbines. In this paper, systematic studies of stand-alone helical Savonius and delta bladed Darrieus turbines were carried out using experimental methods as a precursor to analyze their roles in hybrid configuration. By varying the attachment angle, two hybrid configurations were tested experimentally. Using the optimal attachment angle, six hybrid configurations were investigated numerically based on the commercial software ANSYS FLUENT 17.0. From one configuration to another, only the design of the Savonius turbine was changed. The maximum power coefficient is found to be equal to 0.191 at tip-speed ratio of 0.63 using a helical bladed Savonius turbine with twist angle of 90°. However, the maximum power coefficient reaches 0.232 using a delta bladed Savonius turbine with the same twist angle. This optimization of the novel combined water turbine could be a solution to enhance the generated power.