2018 Volume 46 Issue 6 Pages 348-358
A wind tunnel model of a vertical-axis wind turbine (VAWT) with a motor-driven variable-pitch mechanism has been developed in order to study experimentally on a high efficiency small VAWT. This model has six straight blades (80 mm chord length and 150 mm span) which are attached to both ends of three rotatable shafts revolving on the orbit with 180 mm radius around the rotor axis. Optimum pitch angle changes of the blade are given as rotational motion in the range of tip-speed ratio (TSR) of 0 to 0.9, and as pitching motion in the TSR of 1.0 to 2.0. As a result of wind tunnel tests at the wind speed of 4 m/s, the model reached the maximum efficiency of 0.40 at the TSR of 1.4. This value is 4.3 times larger than the maximum efficiency when the model is operated with the pitch angle of blades fixed to zero.
