Improving the self-starting ability of small VAWT by improving the blade shape

Abstract

A vertical－axis wind turbine (VAWT) is a wind turbine that axis of rotation is perpendicular to the ground. This type of wind turbine is omnidirectional and is expected to have potential for use in urban and city areas with unstable wind conditions. However, they have the disadvantage of poor self-starting performance. Studies have been conducted to improve self-starting performance by using a wind collector plate and by devising the location of the wind turbine, but no decisive improvement has yet been achieved. In this research, wind tunnel tests and CFD were conducted on a small VAWT with an existing blade shape to clarify its power characteristics, and the possibility of using blade end plates and flaps was also investigated. In the low-velocity range, the drag-type wind turbine showed superior self-starting performance, but the torque decreased when the blade was in a certain attitude. In the experiment with the blade end plates, the torque was up to 155% of that without the plates. The flaps on a lift-type wind turbine reduce the flow velocity on the underside of the blade, resulting in higher values of both lift and drag. Therefore, it can be considered that the installation of flaps contributes to improving the self-starting performance of lift-type wind turbines.