Effect Of Radial And Axial Clearance On The Performance Of A Specially Designed Savonius Vertical Axis Wind Turbine

Savonius Wind Turbine SWT has a simple construction and can produce electricity in any wind direction. Although Savonius wind rotor has many advantages but it has a low power coefficient when compared with other horizontal and vertical axis wind rotors. In this paper an experimental study is carried out to investigate the effect of geometrical parameters radial and axial clearances on the performance of SWT in terms of torque coefficient and power coefficient. For this reason analysis is carried out to optimize and improve the operation of such turbines. Two buckets Savonius rotor model was selected designed and manufactured with a diameter of 80 cm and height of 80 cm without having a shaft between the end plates. The designed model was fabricated and tested in a low speed wind tunnel under an open type test section.The results of the present study shows that a maximum power coefficient Cp of 0.076 was obtained at a clearance ea 0.14d in axial direction. The specially designed Savonius wind turbine with clearance er 0.09d and er 0.115d in radial axis are having the highest coefficient of torque than the one in the conventional Savonius rotor.