Small drops, big impact: Over time, rain can damage the surfaces of rotor blades. This reduces the efficiency and profitability of wind turbines, especially at sea. Researchers from institutions of the U Bremen Research Alliance are developing repair solutions to extend the service life of rotor blades.
Picture a large shower cubicle and you are not far off the test bench at the Fraunhofer Institute for Wind Energy Systems IWES in Bremerhaven. The only difference is that the water comes from more than 1,300 needle-shaped nozzles instead of a shower head. The floor of the test stand is fitted with a movable plate which, when rotating, can reach speeds of up to 550 kilometers per hour. Special test objects can be attached to it to represent the rotor blades during the tests. The water droplets hit the surface as they would in nature. The rain intensity is adjustable. A laser-based inspection system automatically scans the surface and documents the smallest changes to determine the effects of the rain drops.
The rain erosion test bench at IWES uses time-lapse technology to simulate the stresses to which the surfaces of rotor blades are subjected during operation. And these are considerable, especially at the leading edges and blade tips. The rotor blade tips rotate at a speed of up to 350 kilometers per hour. The drops hit the surfaces with great force, roughening them, while the sun’s rays and the salts in the sea add to the wear and tear. As the material fatigues, erosion damage can impair the blade’s aerodynamics by increasing the surface roughness and thus making the turbine less effective, even with minimal material abrasion.
“Developing repair solutions that are reliable, durable, and also easily implemented is extremely important for the performance and cost-effectiveness of offshore turbines,” states Sascha Buchbach, working group manager for paint testing and application technology at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen, which, like the Fraunhofer IWES, is a member of the U Bremen Research Alliance.
At the Fraunhofer IFAM, the basis for the use of new materials in wind energy is created in its numerous materials laboratories. Here, material properties are determined, thermal material behavior is analyzed, and aging mechanisms are investigated. The knowledge gained is incorporated into the damage analysis and is particularly valuable for the development of future materials.
The two institutes, Fraunhofer IWES and Fraunhofer IFAM, work together on projects beyond MARiLEP. While IFAM specializes in developing new materials, IWES’ expertise lies in the development and validation of test procedures.
An exciting article on rain protection for rotor blades by U Bremen Research Alliance member institutions was recently published in issue 10 of the U Bremen Research Alliance's science magazine "Impact":
https://www.bremen-research.de/en/impressions/rain-protection-for-rotor-blades
Contact:
Merle El-Khatib
Communication und marketing
Tel.: +49 421 218 60046
merle.el-khatib@vw.uni-bremen.de
About UBRA:
The University of Bremen and twelve federal and state financed non-university research institutes cooperate within the U Bremen Research Alliance. The Alliance includes research institutes of the four major German science organizations, i.e. Fraunhofer Society, Helmholtz Association, Leibniz Association and Max Planck Society, as well as the German Research Center for Artificial Intelligence.
Cooperating in U Bremen Research Alliance:
