The Influence of Ambient Temperature and Liquid Water Content on Electrothermal De-Icing Characteristics of a Wind Turbine Blade Airfoil

Icing on wind turbine blades affects power-generation efficiency. Therefore, it is crucial to provide ice protection for wind turbine blades. This paper investigates how ambient temperature and liquid water content affect the formation and downstream evolution of runback ice during electrothermal de-icing of a wind turbine blade airfoil by numerical simulation. A coupled numerical model integrating external airflow, droplet collection, ice accretion, and unsteady heat conduction is established based on FENSAP-ICE. The simulated temperature agrees well with the experimental data, with an absolute maximum error of 2.02 K and an RMSE of 1.75 K, indicating that the model accurately captures the transient thermal response of the electrothermal de-icing system. The results indicate that after 20 s, the leading-edge ice completely disappears at 268 K, while 0.21 mm of residual ice remains at 258 K. Over the investigated LWC range of 0.5–1.5 g·m−3, a change in trend is observed: the runback ice thickness does not increase proportionally with LWC, suggesting that local freezing capacity may become increasingly important at higher LWC. Furthermore, the freezing front is not stationary but migrates continuously downstream as ambient temperature increases and de-icing proceeds, and the migration rate is higher in the 263–268 K range than in the 258–263 K range. These findings provide qualitative insight for anti/de-icing strategy.