| The distribution range of Wind resources in china is vast and broad. In recent years, due to the increase of extreme weather, such as the winter temperature plummet in some regions, With the effect of humidity and low temperature, wind turbines installed in these areas are facing possible icing events on blades, cabins and anemometers so on, which is closely related to power output and wind turbines’ safety. A large number of studies have shown that icing can cause power losses varying from0.5%to50%of the annual production and mass imbalance between blades, as well as high amplitude vibrations. Under icing condition, the anemometers, wind vanes and temperature sensors can be affected by icing, leading to some unnecessary mistaken actions away from the optimal working conditions. The impact of icing on wind turbines has attracted more attention of many scholars and many experiments, wind field monitoring and numerical simulations were undertaken. However, in most of researches by numerical simulation, icing profile relies on some icing codes, such as LEWICE, TURBICE etc. In this article, the experimental icing profiles were applied into the engineering application, the related analysis and researches about the aerodynamic influence of icing on wind turbine airfoil and blades were estimated.1. According to the mechanism of icing and the condition around all the blades, the icing features of airfoil at different parts of the blade were analyzed in this article, as well as the effect of icing condition, including some typical geometrical parameters, meteorological conditions and the coming flow conditions, on the profile and amount of icing on airfoil and blades.2. In order to explore the impact of rime icing condition on the aerodynamic performance of the icing S809airfoil,6cases with different environmental temperature, liquid water content (LWC) and the coming flow angle of attack(AOA), were calculated over the Reynolds number is1.0×106, and the angle of attack range from-2°to20°. The aerodynamic characteristics between experimental and LEWICE icing airfoils were also calculated and compared. The results indicated that there are obvious differences about the pressure distribution and lift-to-drag ratio between experimental and LEWICE icing airfoils. For S809airfoil with rime icing, the lower the environmental temperature, the higher the LWC and the lower the AOA, the impact on icing airfoil is more prominent.3. In order to analyze and research the effect mechanism of icing on horizontal axis wind turbine performance, compared with the NREL Phase VI wind turbine under the wind speed of 3m/s-17m/s, the rotating speed of72r/min, the aerodynamic parameters and load distribution of this wind turbine with rime icing were calculated. The analysis of the torque output and blade root bending moment indicated that icing will cause flow separation around the blades in advance, and greatly expand the impact area of separation vortex, leading to power loss by up to51%, making wind turbine stall ahead of time and the start-up more difficult. Through the study of aerodynamic load distribution on blades, results showed that for stall-regulated wind turbines, icing can make blade root flap-wise moment increased rapidly under higher wind speed, which could cause blades damage. For variable-speed/variable-pitch wind turbines, icing could cause some measure errors leading to mistaken actions, which make wind turbines working far away from optimal condition and threat the blades safety. On the other hand, it was found that icing in the blade tip region,90%-100%span, has the most pronounced effect on the wind turbine aerodynamic performance. And for some wind turbine blades design in alpine region, this should be the main region of the anti-icing and de-icing system working. |
PDF Full Text Request