Analysis on the Element Unsteady Flow Speed Field of Straight-bladed Vertical Axis Wind Turbine with Three Blades

Abstract

The flow field around a vertical axis wind turbine is much complicated because the blades pass in non-uniform flow field by the blade wake and the variation with the azimuth angle of the blade's angle of attack during rotation. To explore the relationship between the SB-VAWT and the attack angle of the wind turbine blades during rotating, and to clear the speed distribution and variation in quadratic element flow field, wind velocity in flow field around the straight-bladed vertical axis wind turbine with three blades is measured using laser Doppler velocimetry(LDV) technology, and velocity distribution relationship of flow field around wind turbine in different tip speed ratios are obtained in the wind tunnel test. Based on the established mathematical model of the blade movement at attack angle changes of the SB-VAWT in different values of azimuths, the velocity distribution relationship of flow field around wind turbine in the different tip speed ratios wis analyzed utilizing the movement analysis software.The following conclusions can be obtained:The turbulence is generated in the region of the blade leading edge, and the relative wind speed around the blade is larger; There is a wide low wind velocity field will appear from the wind turbine internal region to downstream area, along with increase of tip speed ratio, there is an expanding tendency of low wind velocity region.