Analysis on wake deviation and turbulence characteristics of horizontal-axis wind turbine under yawed condition
GUO Maofeng1, ZHANG Liru2,3*, LI Deyin2, WANG Xueli2, NIU Jiajia2
1. Hohhot Thermal Power Plant, Northern United Electric Power Co. Ltd., Hohhot, Inner Mongolia 010030, China; 2. College of Energy and Power Engineering, Inner Mongolia University of Technology, Hohhot, Inner Mongolia 010051, China; 3. Key Laboratory of Wind Energy and Solar Energy Technology, Inner Mongolia University of Technology, Ministry of Education, Hohhot, Inner Mongolia 010051, China
Abstract：Numerical simulations combined with theoretical analysis were used to analyze the wake of a 300 W horizontal-axis wind turbine with S-shaped airfoil under different wind speeds and yaw angles to explore variation characteristics of the wake. At first, the relationship between yaw angle and wind turbine output power was derived; then the deviation of the wake center and the variation of turbulence intensity in the wake were analyzed at different yaw angles. The results show that the pressure difference across the airfoil surfaces decreases with increasing yaw angle. The positive and negative pressure peak on the blade surfaces occurs once at every 120° azimuth angle. The critical interval of adverse yaw angle, which can cause obvious loss of wind turbine output power, is 10°-15°. The deviation degree of wake velocity center towards the negative direction of the X-axis is intensified with increasing yaw angle when the axial length is less than 1D. As the axial length being longer than 1D, the deviation degree increasing when the yaw angle is smaller than 15°, and decreases when the angle is greater than 15°. As the yaw angle increases, the maximum turbulence intensity in the wake is increased, and the wake turbulence intensity is restored quickly, thus the wake is shortened. The turbulence intensity distribution on both sides of the wake is asymmetrical and shows different variation patterns with yaw angle, resulting in the wind turbine wake having a more complicated turbulence environment.
