Enhancing the Aerodynamic Performance of the Savonius Wind Turbine by Utilizing Quarter Elliptical Supplementary Blades

Abstract

The application of wind energy leads to reduced greenhouse gas emissions and dependence on conventional sources of fuels. Nevertheless, traditional Savonius wind energy systems suffer from high negative torque and low efficiency. Therefore, the optimization of the blade shape of the Savonius wind turbine is an effective approach to enhance the use of clean and sustainable wind energy. In this work, selecting supplementary blades with quarter elliptical shapes is proposed to optimize the aerodynamic efficiency of the Savonius rotor by enhancing the amount of captured wind at minimal cost. The turbulence model SST/k–ω is used in ANSYS fluent to numerically simulate the performance of the rotor with supplementary blades. As a function of tip speed ratio (TSR), the torque coefficient (Ct) and power coefficient (Cp) are computed. Furthermore, the total pressure, velocity, and streamlines are estimated and analyzed. The results showed that the supplementary blades have the ability to enhance the output power of the turbine by lowering the negative drag behind the returning blade. Overall, the new configuration enhances the suction vortices and reverses flow, leading to better aerodynamic performance. The maximum Cp for the new configuration is observed at TSR = 0.5 with a value of 0.181 which is 13.1% better than the conventional Savonius turbine.