Application of Guide Blades for Improving the Performance of Savonius Wind Turbines

The application of guide blades is an appropriate method for improving the aerodynamic performance of Savonius wind turbines. Guide blades gather wind energy around the turbine and guide them into the concave side of the Savonius rotor. In this paper, a numerical investigation is conducted to evaluate the effect of the guide blades on the performance of Savonius turbines. ANSYS Fluent 16.0 software is applied for the simulation of turbulent and transient flow around the turbine. Suggested designs for guide blades are 4, 5, and 6 blades which are located in the angles of 30, 40, 50, and 60 degrees. The numerical results of power and torque coefficients show that guide blades have significantly improved the performance of Savonius turbines.  For a turbine with 5 guide blades located at the angle of 30 degrees, maximum power coefficient is 0.51, which indicates an increase of 183% compared to a single Savonius turbine without the guide blades. For turbines with 4 and 6 guide blades, maximum power coefficients are 0.42 and 0.49 respectively; this finding shows an increase of 133% and 171% in comparison with a single Savonius rotor without guide blades.