Study on the Effect of Mixed-Phase Icing on the Aerodynamic Characteristics of Wind Turbine Airfoil

Wind turbines operating in high-altitude and cold regions are susceptible to icing phenomenon, which is a serious threat to the power generation efficiency and operational safety. On the basis of the current research on supercooled droplet icing, mixed-phase icing is investigated. Based on icing numerical simulations under mixed-phase conditions, the aerodynamic characteristics of wind turbine airfoils before and after icing are analyzed. The results indicate that as the icing thickness increases, the aerodynamic characteristics of the airfoil gradually deteriorate, with the lift decreasing by 40.2% and the drag increasing by 135.2%. The aerodynamic characteristics of airfoil after icing are analyzed under both glaze and rime ice conditions and compared to those of the clear airfoil. The results show that icing leads to a decrease in the lift coefficient and an increase in the drag coefficient of the airfoil. This deterioration is primarily due to the fact that icing causes premature separation of the airfoil airflow, and icing can cause obstruction at the leading edge, which leads to the formation of local vortices and a decline in aerodynamic performance. The effects of icing on the aerodynamic characteristics of wind turbine airfoils under glaze and rime ice conditions are compared, and the lift-to-drag ratio decreases by 87.9% under the glaze ice condition and by 62.4% under rime ice conditions. The results show that the effects of mixed-phase icing under glaze ice conditions has a more severe impact than under rime ice conditions.