A simulation investigation the performance of a small scale Elliptical Savonius wind turbine with twisting blades and sloping ends plates

Abstract

Savonius wind turbine is among of simplest type of vertical axis wind turbines to produce the power from wind. Elliptical blades one of adopted geometry to design the Savonius turbine rotor. One of the most important measures to improve the performance of elliptical Savonius turbine rotor by developing the blade geometry. In this study, a CFD simulation used to investigate the effect of geometrical parameters of the small scale elliptical Savonius turbine rotor (ESTR) with inner surface wavy blades. The simulation has been implemented in a in a two configurations design models, ESTR models with twisting angle in range of (5˚ to 45˚) and ESTR models with tilt angle of end plates (3˚ to 15˚) with a constant Aspect ratio of 1 and overlap ration of 0.2. The performance evaluation were in terms of power coefficient and torque coefficient as a function of tip speed ratio. The numerical results show that an increase in the maximum power coefficient with increase of twist angle and tilt angle until optimum values of 30˚ and 12˚ for the twist angle and tilt angle, respectively. Although in all configuration show a good increase in power coefficient but there are a significant increasing in maximum power coefficient for ESTR model with twist angle of 30˚ which was 3.7% while the increasing reach to 14.55% at ESTR model with tilt angle 12˚ at tip speed ratio of 7. As well as, these two models provide a jump in power coefficient for a different range of tip speed ratio compare to previous model of ESTR.