Review of analytical techniques for assessing rain drop erosion resistance of materials

In the industry of renewable energy, wind has been expanding to become one of the biggest markets. With this increase in popularity, the maintenance of wind turbines is crucial, especially the care of the turbine blades. Rain erosion is widely accepted as one of the key areas of interest, as a even a 2-3% loss in annual energy output significantly reduces the energy efficiency. Inspection of turbine blades as of late is very basic, simply involving a visual observation which is accompanied by photographs of the damage. Recent studies investigating the rain erosion of turbine blade materials show that this standard procedure fails to characterise the loss of aerodynamic efficiency in these turbine blades or evaluate their performance in an inter-study comparative approach. Previous studies have focused on using smaller test coupons and the industry moving in the direction of leading edge profile samples, there is a broad consensus that whirling arm type test rigs are the most applicable testing regimes. However, there is little overlap in the analysis used in different studies. This review will look into the various techniques used to inspect and characterise the samples, materials and performance used in rain erosion testing. The focus will be on their practicality, benefit and application to overall use within the industry of wind energy.