Abstract
This paper describes the performance of a vertical axis wind turbine with variable-pitch straight blades. Our aim is to get basic data to increase the efficiency of micro vertical wind turbine systems. The proposed variable attack angle mechanism has an eccentric point that is different from the rotational point. The main feature of the mechanism is to be able to change attack angles according to the rotational angles of the blades without actuators.We measured the performance of wind turbines with a flat plate, asymmetric and NACA63_4-221 airfoil sections by using an open circuit type wind tunnel. The wind turbine with variable-pitch straight blades has a directivity for the wind. It was found that the performance of the wind turbine is dependent on the angle of attachment, the amplitude of the fluctuating pitch angle, the number of blades and chord length of the airfoil. The efficiency of the wind turbine with NACA63_4-221 airfoil section is larger than that of the other wing section.
