An Effect of Twist Angle on Performance of the Vertical Axis Wind Turbine Blades

The Vertical Axis Wind Turbine (VAWT) represents a unique form of power generation technology. Recent studies have shown that vertical axis wind turbine is more suitable in low wind speed areas. In order to increase the efficiency of the power generated, it is necessary to design turbine blades in accordance with the specifications of vertical wind turbines that operate at low rotation speed. The present work uses a variable twist angle of the Savonius blades with a variation in twist angles of 0?, 30?, 60?, 90?, 120?, 150?, and 180?. The blade is tested at wind speed used of 3 and 4 m/s in wind tunnel. The performance of the blade evaluated is in terms of tip speed ratio (TSR), torque, and coefficient of power (Cp). The results showed that maximum TSR and torque are obtained with twist angle of 90?. The TSRs are 0.381 and 0.445 at a wind speed of 3 m/s and 4 m/s, respectively. The torque is 0.33 Nm at wind speed of 3 m/s as well as at wind speed of 4 m/s. Meanwhile, the maximum Cp is occurred at wind speed of 3 m/s. The values are 0.468, 0.449 and 0.401 at twist angle of 0?, 90?, and 180?, respectively. Increasing wind speed decreases the Cp. The greater the wind speed, the greater the energy converted. However, the actual power also depends on the profile of the turbine blades. The highest actual power is obtained by blades with a twist angle of 90?.