Wind turbines operating in cold regions are prone to freezing in winter, which can affect their performance and safety. To resolve this situation, the development of blade anti-icing technology has attracted widespread attention. In this study, a type of biochar/polypyrrole coating was obtained through synthesis on the surface of biochar. After characterization, it was found that the porous structure, irregular dents, and bumps on the surface of biochar/polypyrrole material contributed to the formation of a nanoscale roughness structure with a typical super-hydrophobic nanostructure. Additionally, it had a sufficient surface area. The wetting characteristics of the coating were analyzed with the assistance of a contact angle measurement instrument. The contact angle of the coating was determined as 151°, which indicates the excellent hydrophobic properties of the coating. Icing wind tunnel tests were carried out to evaluate the anti-icing effect of biochar coating and biochar/polypyrrole coating at different ambient temperatures and wind speeds. Compared with uncoated leaves, the icing area of biochar/polypyrrole coating was reduced. Additionally, the anti-icing effect of biochar/polypyrrole coating was most significant. This study provides a practical reference for the research of anti-icing coating on wind turbine blades.

Wind turbines in cold and humid regions face significant icing challenges. Heating is considered an efficient strategy to prevent ice accretion over the turbine’s blade surface. An ice protection system is required to minimize freezing of the runback water at the back of the blade and the melting state of the ice on the blade; the law of re-freezing of the runback water is necessary for the design of wind turbine de-icing systems. In this paper, a wind tunnel test was conducted to investigate the de-icing process of a static heated blade under various rime icing conditions. Ice shapes of different thicknesses were obtained by spraying water at 5 m/s, 10 m/s, and 15 m/s. The spray system was turned off and different heating fluxes were applied to heat the blade. The de-icing state and total energy consumption were explored. When de-icing occurred in a short freezing time, the ice layer became thin, and runback water flowed out (pattern I). With an increase in freezing time at a low wind speed, the melting ice induced by the dominant action of inertial force moved backward due to the reduction in adhesion between the ice and blade surface (pattern II). As wind speed increased, it exhibited various de-icing states, including refreezing at the trailing edge (pattern III) and ice shedding (pattern IV). The total energy consumption of ice melting decreased as the heat flux increased and the ice melting time shortened. At 5 m/s, when the heat flux was q = 14 kW/m², the energy consumption at E_A at t_δ = 1 min, 5 min, and 7 min were 0.33 kJ, 0.55 kJ, and 0.61 kJ, respectively. At 10 m/s, when the heat flux was q = 14 kW/m², the energy consumption at E_A at t_δ = 1 min, 3 min, and 5 min were 0.77 kJ, 0.81 kJ, and 0.80 kJ, respectively. Excessive heat flow density increased the risk of the return water freezing; thus, the reference de-icing heat fluxes of 5 m/s and 10 m/s were 10 kW/m² and 12 kW/m², respectively. This paper provides an effective reference for wind turbine de-icing.