EXPERIMENTAL INVESTIGATION OF PERFORMANCE CHARACTERISTICS FOR SAVONIUS-STYLE VAWTS: A COMPARATIVE STUDY

Savonius-style wind turbines are mainly gauged by two types of coefficients namely: (i) coefficient of power (C-P) and (ii) coefficient of torques (C-T). Coefficient of power is defined as the ratio of power generated by the turbine to the total power available to the turbine from the free-flowing wind. This is synonymous to the operational efficiency of the wind turbine. Coefficient of torque reflects the torque generating ability of the turbine. In this manuscript, experiments have been performed using three different types of rotor profiles for Savonius-style wind turbines (SSWTs) namely, classical SSWT, Benesh type SSWT and elliptical shaped SSWT using oriented jets. Using deflector plates the orientation of jets have been varied from 20 degrees to 70 degrees. Addition of deflector plates to the wind turbines, assists in maximizing the utilization of wind energy. Experiments have been performed in the laminar air flow. Mechanical loads have been used to study Coefficient of performance (C-P) and coefficient of torque (C-T) as a function of tip speed ratio (TSRs). The velocity of the wind is adjusted by varying the rheostat that controls the AC motor for the wind tunnel systems. Experimental results indicated that optimum performance could be achieved from all three types of SSWT variants at TSR similar to 0.70. Out of the three designs studied in this manuscript, elliptic shaped SWT yielded best coefficient of performance equal to 0.39 at TSR = 0.70.