Design and experimental validation of a hierarchical microstructured surface for anti-icing

In cold environments, droplet freezing and ice accretion can significantly deteriorate the aerodynamic performance of wind turbine blades, while also inducing additional loads and operational safety risks. To support the efficient and stable design of anti-icing surfaces, this study proposes a simulation-data-driven optimisation method for the geometrical parameters of a hierarchical microstructured surface. First, a numerical model of droplet impact on hydrophobic hierarchical microstructured surfaces was established based on CFD. A single-factor analysis and an improved particle swarm optimisation algorithm were combined to optimise the microstructure's geometrical dimensions. Subsequently, the optimized hierarchical microstructured surfaces were fabricated on aluminium alloy surfaces via laser sintering. Droplet impact tests, abrasion tests, freezing adhesion tests, and low-temperature icing tests were conducted to evaluate the dynamic wettability, mechanical durability, and anti-icing performance of the fabricated surfaces. The results demonstrate that the optimized hydrophobic hierarchical microstructured surface effectively suppresses droplet spreading and maintains stable interfacial regulation capability under different Weber numbers and droplet sizes. Durability tests further showed that the maximum spreading factor increased only slightly after repeated sandpaper abrasion. At −10 °C, the frozen-droplet detachment force on the hydrophobic hierarchical microstructured surface decreased to 0.2 N, indicating that the proposed hierarchical microstructured surface could effectively weaken ice adhesion and exhibit favourable icephobic performance. The subsequent icing tests further confirmed that the hydrophobic hierarchical microstructured surface effectively reduced ice-layer formation and limited ice accretion. The proposed design strategy for hierarchical microstructured surfaces provides a feasible approach for developing anti-icing engineering surfaces in cold environments.