Investigation of Arc Angle Rotor Blade Variations Effect of Savonius Vertical Axis Wind Turbine on Power and Torque Coefficients Using a 3D Modeling

Unacceptable air pollution leads to a remarkable increase in the consumption of renewable energy. Wind energy is known as one of the conventional renewable sources, therefore installation of wind turbines has increased over the past three decades. Savonius wind turbine is one of the types of vertical axis wind turbines. This type has many advantages namely low noise, self-start capability and closer spacing. Some studies has been carried out to increase the efficiency of wind turbines by optimizing the geometry. In the present study, the arc angle of Savonius turbine blades and its effects as one of the geometric parameters affecting the efficiency of the turbine have been investigated within a CFD method. The amount of arc angle, also called camber angle, is very effective in the optimal efficiency of Savonius wind turbine. To investigate this issue, three different arc angles in the different tip speed ratios have been evaluated. The values of power and torque coefficients which play a vital role in the efficiency of the above turbine have been considered with respect to the changes in the amount of three different arc angle. The results of three-dimensional numerical solution show that the highest power and torque coefficients are obtained with values (0.0261) and (0.501) at a 180 degree arc angle, respectively. Adopting values other than the above value will cause a significant drop in efficiency.