Experimental Study on the Wake Field and Interaction of Wind Turbines
YANG Rui;WANG Xiaoli;WANG Qiang;ZHANG Zhiyong;School of Energy and Power Engineering,Lanzhou University of Technology;Wind Turbine Engineering Technology Research Center of Gansu Province;
The wake field and interaction of wind turbines are measured by pressure gradient precision anemometer in this paper. For a single wind turbine,the axial velocity of the wake at different distance is measured; for two wind turbines,the axial velocity of wake at different distance after downstream wind turbine( the second wind turbine) is measured. Due to the situation that the downstream wind turbine is located in the wake field of upstream wind turbine( the first wind turbine),the trailing is superimposed in the process of wake downward expansion,and the changes of downstream wind turbine wake field are more complex. The experiment results show that the single wind turbine wake region has speed loss due to the wind wheel rotation and flow attenuation,and the speed loss of wake is decreased gradually with the axial distance increasing of downstream wind turbine. The axial velocity and axial induced velocity show a strong symmetry in the horizontal direction,and there are high velocity regions further away from the center of the measurement because of the shedding of tip vortex when wind turbine blade rotating. The velocity loss in the wake of the downstream wind turbine is more serious when the downstream turbine located in the wake field of upstream wind turbine. Due to the instability extension of upstream wind turbine wake,wake superposition,and the fluctuation phenomenon of axial velocity and axial induced velocity is obvious. Also,the influence of upstream wind turbine on the downstream wind turbine is gradually weakened with the increase of distance between two wind turbines and axial distance of the downstream wind turbine.