The effect of inner blade position on the performance of the Savonius rotor

Abstract

In this study, the effect of the inner blade position on the performance of the Savonius rotor has been investigated numerically to determine the best position of the inner blade. Five values of inner blade angles are adopted (180°, 160°, 140°, 120°, and 100°). Two-dimensional simulation is performed for the conventional rotor, rotor with the inner blade tip parallel with rotor tip, and rotor with the inner blade parallel with rotor root keeping the main rotor diameter constant in each case. The simulation has been achieved using the k-ε/realizable turbulence model with the assist of the ANSYS-Fluent solver. The torque coefficient (Ct) and power coefficient (Cp) are estimated as a function of tip speed ratio (TSR) for each case. Finally, the total pressure, velocity, and streamlines are obtained and analyzed. The numerical results demonstrated the maximum Cp to be 0.1885 at TSR equal to 0.5 when the inner blade is placed parallel with rotor tip with inner blade angle of 120°. Moreover, results found that the maximum Ct is 0.407 at TSR = 0.4 for the rotor with 180° inner blade. Furthermore, the peak value of the torque found to be generated at the azimuth position of (θ = 105°).