On the Performance of a Modified Triple Stack Blade Savonius Wind Turbine as a Function of Geometrical Parameters

The Savonius wind turbine is one of the most well-known vertical axis wind turbines with insensitivity to wind direction, flow turbulence, and high torque generation. These turbines can extract up to 20% of the energy from the wind. This study numerically analyzes the performance of a modified Savonius wind turbine equipped with secondary blades and slots. The k-ε standard method is used to simulate the turbulence flow around the turbine, and the simulation is performed using the ANSYS FLUENT 18.2 commercial code. The effects of distance between the main blade and the secondary blade, position of the secondary blade, the width of the main blade’s slot, and the profile of the secondary blade on the produced torque are studied and analyzed. The simulation is performed at four wind velocities: 3, 4, 5, and 6 m/s. The results showed that the output torque at the secondary blade angular position β = 130 is higher than other angles. Furthermore, by increasing the radius of the additional blade from R = 25 to 43 mm, the torque is improved, and the area below the output torque curve is increased. Moreover, the results showed that creating a slot on the main blade equipped with a secondary blade has a significant impact on the produced torque; however, the geometrical parameters of the proposed rotors should be adjusted accurately to find the best case in terms of the produced torque.