Wind turbine blades are constantly exposed to weather conditions, which wear and degrade the surface [1]. Depending on the site of the plant, rain is the main driver for this wear. This rain erosion becomes apparent, when the coating — usually on the leading edge — shows a rough surface or even the bare GFRP looms.
Increased surface roughness usually goes along with diminished performance. This surface erosion occurs mostly near the tips of the blades, where most power is converted. Maintenance teams replace the damaged coatings in costly rope-based operations. To extend maintenance intervals and select the best coating, better understanding of the loads and the non-linear development of erosion damage is necessary.
Therefore a test rig to simulate realistic erosion loads is constructed. The velocity between the surface and the droplet is created by a rotating arm with a vertical axis and a stationary nozzle in one side, similar to the rotating arm apparatus in [2], but much smaller. Our approach is to use relative velocities between droplets and coating which are comparable to the ones seen on wind turbines, as well as a realistic droplet size distribution [3] and ambient pressure.
Rotational speed, temperature, vibrations, flow rate, electric voltage and current are constantly measured to ensure safe operation and repeatable measurements.
