Performance Improvement of Savonius Hydrokinetic Turbine Using Upstream Crescent Shape Deflector

Abstract The use of non-renewable sources such as coal, natural gas, and oil for energy generation has caused negative environmental impacts. In response, clean and sustainable energy technologies are being rapidly developed. Hydrokinetic turbines, which can harness kinetic energy from free-flowing water in various settings, have been studied for their potential to generate electricity. The Savonius turbine is a hydrokinetic turbine that utilizes drag force and has a straightforward design that is independent of flow direction but suffers from lower efficiency. In this work, the effect of a crescent-shaped deflector installed upstream of the returning blade on the performance of the Savonius hydrokinetic turbine has been investigated. The numerical results indicate that the overall performance of the Savonius hydrokinetic turbine was positively influenced by the installation of the crescent deflector upstream, with a maximum power coefficient (Cp) of 0.264 achieved at a Tip Speed Ratio (TSR)=0.8. A further increase of up to 19.51% in the coefficient of power (Cp) of the Savonius hydrokinetic turbine was obtained at TSR=0.8 when a flat plate deflector upstream of the driving blade was installed along with a crescent-shaped deflector.