Dynamic response mechanism of raindrop impact on leading edge of large wind turbine blades

With increasing scale of offshore wind turbine design in recent years, the problem of rain erosion failure at leading edge of blades has become increasingly prominent, it not only affects wind energy conversion efficiency of a wind turbine unit, but also poses a potential threat to its stable operation. Here, the smooth particle hydrodynamics (SPH) was used to study constitutive relation inside raindrops, and the representative volume element (RVE) model of a blade leading edge was established with finite element method (FEM). SPH-FEM coupled model was built to study the formed raindrop impact response process on blade surface. Considering actual working conditions of natural rainfall, a raindrop size model related to rainfall intensity and a spatial distribution model of raindrops were built. By simulating a single raindrop impact, impact load on blade surface and velocity distribution inside a raindrop were studied to clarify the physical process of raindrop impact. Through analyzing stress and strain fields caused by impact, potential damage areas were evaluated. The simulation model for multi-raindrop impacts was built to study coupling actions among impact stress fields and the cumulative effect of plastic strains on coating surface. The study results showed that water hammer impact is the key factor to cause accumulation of plastic strain; although stress response amplitude in lateral spraying stage is small and exhibits a certain disordered feature, if there is a multi-raindrop coupled impact, stress peaks can appear in the coupled zone and have a potential impact on blade deformation and failure. © 2024 Chinese Vibration Engineering Society. All rights reserved.