| The icing situation of wind turbine blade, which will reduce both efficiency and the generating capacity of wind energy conversion, can cause serious harm to wind farms. Covered with ice, wind turbine are easier to overload causing accidents like wind turbine collapse and the break off of blades. Moreover, unbalanced icing situation will lead to imbalanced rotation and finally reduce the service life of wind turbine. However, nowadays wind farms are more likely to adopt passive methods such as coatings which can merely postpone the icing process rather than hinder icing process.To achieve the goal of active anti-icing and de-icing, this paper presents the method of electric heating. By analyzing the thermal equilibrium of electric heating, the critical anti-icing and de-icing heat flux model is established. In order to improve de-icing efficiency, both the melting process and nonuniform layout of heat source are analyzed. Besides, calculation method of ice shedding time is obtained by analyzing the ice layer shedding process. Main achievements are as follows:â‘ By analyzing the thermal equilibrium of electric heating, the threshold anti-icing and de-icing power density model is established and verified by experiments. Moreover, the influence of environment factors is obtained.â‘¡Through both theoretical analysis and experiments of the interface of blade and ice leyer, the influences of melting water and nonuniform layout of heat source upon ice layer is discussed, and method for improving de-icing efficiency is proposed.â‘¢Ice layer shedding process is analyzed in order to simulate warm up time of the interface. Experiments are carried out to investigate the force that needed in ice shedding process during electric heating process. Consequently, the relation between ice-melting energy consumption and the force is obtained along with the calculation method of ice shedding time. Experiment shows that the two results are basically consistent. |
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