A Comparative Study to Examine Rain Erosion Characteristics Upon Impingements of Freshwater and Saltwater Droplets Pertinent to Offshore Wind Turbine Operation

The installation of offshore wind turbines has increased in the last two decades due to their superior size and power production capabilities. As a result, the need to study the performance of these turbines in extreme weather conditions has arisen. Leading-edge erosion is a prevalent problem, which is further exacerbated by the corrosive effects of saltwater in the sea spray affecting offshore wind turbines. This study aims to characterize the long-term erosion characteristics of freshwater and saltwater due to the sustained impact of rainfall and sea-spray generated water droplets, and understand the differences between the two. Accelerated testing is performed experimentally by impinging the test samples with water droplets at high velocities and high Liquid Water Content levels. The surface wettability characteristics are measured before, during, and after the erosion process for both freshwater and saltwater erosion for two different coatings: a hydrophilic enamel coating and a superhydrophobic protective coating. Qualitative characterization of the surface morphology was also performed using optical microscopy to identify the differences between the freshwater and saltwater erosion mechanisms.