The thesis studies the aerodynamic characteristics of vertical-axis wind turbines, which is divided into two parts. The first part of this study experimentally investigates the effects of rotor geometries on the turbine Power output, including the airfoil type, blade weight, rotor diameter, airfoil chord length. The results show that the rotor with symmetric airfoil, chord length of 15 cm, blade length of 30 cm and rotor radius of 30 cm exhibits the highest Power output among the test rotors.
The second part of this thesis investigates the effects of stator on the drag-type rotor Power output, which is placed around the rotor. The stator includes top and bottom circular plates, and a number of flat plates placed between them. These flat plates are arranged equal-angled and tangent to a circle, which direct some air into the interior of the stator, and block some air from the stator. In this way, a vortical flow is able to be created inside the stator, which always forces the drag-type blades rotated during their rotation motion. Numerical investigations of the 4-, 6-, 8-, and 12-plate stators indicate that vortical flows are generated inside the stators. The experimental investigations show that the 4-plate and 12-plate stators have the highest and lowest effects on rotor Power output, while they are the most and least sensitive to the wind direction, respectively. In summary, the 6-plate stator exhibits the optimum effect on rotor Power output.