Experimental Investigations on the Effect of Overlap Ratio and Blade Edge Conditions on the Performance of Conventional Savonius Rotor

Abstract

The torque of a conventional Savonius rotor is studied experimentally for overlap ratio from 0.10 to 0.70, blade edge condition (flat and round) and the change in Reynolds number. The results indicate that the coefficient of static torque improves marginally for round edged rotors for rotor angles up to 45°. The coefficient of static torque decreases as the overlap ratio is increased to 0.70 from 0.50 and is independent of the Reynolds numbers studied in the range between 120000 to 200000. Wind tunnel blockage ratio is studied. The power coefficient increases with the increase in the Reynolds number, whereas the coefficient of static torque is independent of the Reynolds number in the range studied. The coefficient of power, torque coefficient and coefficient static torque are independent of blockage ratios at a given Reynolds number.