Performance characteristics of the Savonius turbine

The paper presents performance investigation of the Savonius turbine both in terms of starting and power extraction characteristics. Effects of the number of blade and the overlap ratio were investigated experimentally using a wind tunnel at a wind speed of 4.45 m/s. Results show that the number of blades and the overlap ratio have a great impact on both performances. In terms of starting, the two-bladed rotor was found to be able to produce higher peak torque than the three-bladed case. However, the three-bladed rotor has a greater starting capability due to its more continuous torque production. The overlap ratio was found to reduce the amount of torque and hence their starting performance. With regard to power extraction characteristic, the three-bladed rotor without the overlap ratio was found to exhibits the highest performance.