Rain erosion damage initiation assessment of wind turbine blades leading edge protection systems based on laboratory testing data: a review and case study

Protecting wind turbine blades, especially offshore, is challenging due to harsh atmospheric conditions. Leading edge protection (LEP) coatings prevent damage from high-speed droplet impacts. Rain erosion harms the blade surface, reducing aerodynamic performance and power production, leading to costly repairs. The wear damage caused by raindrop impacts can be viewed as a fatigue process, where damage accumulates until a specified damage limit is reached. Springer analytical model, cited extensively in rain erosion impact applications, has been used by wind industry with a recommended practice, DNVGL-RP-0573, to evaluate damage progression and to assess blade material reliability. It suggests calculating accumulated erosion damage using accelerated rain erosion test performance results to determine the model's material strength parameters. Quantifying the severity of erosion in wind turbine blades is challenging due to various factors, including meteorology, aerodynamics, materials science and wind turbine dynamics. All these modeling evaluations require material characterization data that depends on initial laboratory data performance that can be extrapolated to field installations. This work reviews the model to estimate rain erosion damage initiation in wind turbine blade leading edge protection systems and analyzes its industrial application. Both methodologies are assessed using real cases with field blade erosion data, allowing a complete comparison of modeling input data considering material fundamental properties and laboratory rain erosion testing fit data. Obtained modelled lifetime predictions agree well with field inspection data, and hence validate the models on the application with referenced coating materials.