Research on the Change of Airfoil Geometric Parameters of Horizontal Axis Wind Turbine Blades Caused by Atmospheric Icing

Abstract

Icing can significantly change the geometric parameters of wind turbine blades, which in turn, can reduce the aerodynamic characteristics of the airfoil. In-depth research is conducted in this study to identify the reasons for the decline of wind power equipment performance through the icing process. An accurate experimental test method is proposed in a natural environment that examines the growth and distribution of ice formation over the airfoil profile. The mathematical models of the airfoil chord length, camber, and thickness are established in order to investigate the variation of geometric airfoil parameters under different icing states. The results show that ice accumulation varies considerably along the blade span. By environmental temperature drop, the minimum and maximum extents of ice accumulation are observed near the blade root (0.2 R) and the blade tip (0.95 R), respectively (R represents the blade length). The icing process steadily increases the chord length and decreases the airfoil curvature, reaching the largest value at the blade tip region. Furthermore, the maximum curvature is reduced to 41.50% of the original curvature. The maximum camber position of the airfoil moves towards the trailing edge, and the most prominent position occurs at the middle blade region (0.6 R), where it moves back by 19.43%. Ice accumulation steadily increases airfoil thickness. It leads to the maximum thickness growth of 53.40% that occurs at the blade tip region and moves forward to the leading edge by 10%. The research results can provide the required theoretical support for further monitoring the blades operating conditions to ensure reliable wind turbines’ operation.