Numerical prediction of improvement of a Savonius rotor performance with curtaining and fin addition on blade.

Savonius turbine is a vertical axis wind turbine (VAWT) which is suitable to operate at low wind velocities. The experimental investigation to improve its performance is a big challenge as; it is expensive, complicating and time consuming. Numerical prediction using CFD simulation could be a valuable alternative. This paper introduces a new modification of Savonius wind rotors to improve its performance. The proposed modification consists of a curtain arrangement together with fin addition on blade. The effect of the proposed modification was predicted using a CFD simulation employing 'ANSYS FLUENT 16′. The curtain arrangement was located in front of the rotor to avoid the opposing torque to the rotor rotation. The fins were added to exploit the space in the blade for guiding the wind flow. The performance of the rotor with different curtain arrangements and variable number of fins was predicted and assessed against that of the conventional rotor. This comparison aimed to optimize the geometrical data of the proposed curtain arrangement with the number of added fins. The maximum power coefficient of the Savonius wind rotor was found to be increased to about 42 % with the optimum curtain arrangement (lengths of the curtain blades 1000 and 1150 mm and the angles of the curtain blades 30 and 50) together with adding only one fin. The simulation results showed that the performance of Savonius wind rotors could be significantly enhanced with a proper selection of curtain arrangement and number of fins to be added on the blade. [ABSTRACT FROM AUTHOR]