Performance of Vertical Axis Wind Turbine with Variable-Pitch Straight Blades by a Linkage Mechanism

Abstract

This paper describes the performance of a micro vertical-axis wind turbine with variable-pitch straight blades. The proposed variable-pitch angle mechanism has an eccentric point that is different from the main rotational point. A feature of the mechanism is to be able to vary the pitch angle of blades according to the azimuth angle of the main-links, without actuators. The performance of wind turbines was measured by using an open circuit type wind tunnel. The performance of the vertical axis wind turbines with this mechanism was better than that those with fixed pitch blades. The wind turbine with variable-pitch straight blades has directivity for the wind. It was found that the performance of the wind turbine is dependent on the offset of blade pitch angle, the amplitude of the pitch angle, the size of the turbine, the number of blades and the airfoil profiles.