Aerodynamic characteristics of Straight-bladed Vertical Axis Wind Turbine with a curved-outline wind gathering device

Abstract

In order to improve the aerodynamic performance of the Straight-bladed Vertical Axis Wind Turbine (SB-VAWT), a Wind Gathering Device (WGD) with curved-outline installed at the up and down of the rotor was proposed to obtain more wind energy. The B-spline curve construction was applied to the study of suitable curved outline of the WGD. The studied structure parameters of the WGD included the radius ratio of the upper and lower plan, inlet angle and the outlet angle. Firstly, based on the method of quadratic rotary orthogonal combination design, the static performance effects of these parameters of WGD on SB-VAWT were researched by three-dimensional numerical simulation. A combination of optimum curve parameters was obtained. The influence of the WGD with different structure parameters on the starting characteristics of SB-VAWTs was also calculated to investigate the fluid field effects of WGD on rotor. Furthermore, the wind tunnel tests were carried out on the rotor with and without WGD included the rotational speed performance and output power characteristics. The results showed that both the static and dynamic performance of SB-VAWT was increased in some degree by adding the WGD with curved-outline. The maximum starting moment of SB-VAWT could be increased by 14.8%. The improvement is more obvious under the condition of low wind speed. This research can be as a useful reference for the performance improving of SB-VAWT.