ABRASION/ IMPACT RESISTANT COATINGS FOR WIND TURBINE BLADE PROTECTION

Technical Report · Tue Jun 26 00:00:00 EDT 2018

OSTI ID:1457138

Wind turbine blade erosion, due to impacts with particles (sand), water and ice during normal operation, is a major problem in this industry. In most wind turbine cases the polymer/glass-fiber or polymer/carbon-fiber composite blades are expected to last for 20 years in the field. However, without maintenance and repair, the blades’ actual service life can be significantly diminished, and the overall turbine efficiency can severely suffer. In the harshest environments, leading-edge erosion is evident as soon as two years after installation. As the edges erode, the airfoil is affected and, if not immediately remediated by maintenance and repair crews the overall production efficiency of the turbine can be drastically reduced. Current repair products such as epoxy-based fillers and/or solvent-based paints have very limited abrasion-resistance capabilities. In addition, wind protective tapes cannot be applied over chipped and damaged leading/trailing edges. With the elongation of turbine blades past 100 meters, and the increase in age of all existing installations, more than 2 billion meters of leading edge turbine blades will require maintenance and repair. And, as more of the world’s energy consumption depends on wind and other renewable energy sources, effective leading edge protection (LEP) will become more and more valuable to minimize or prevent the downtime of service interruptions. The purpose of this work was to develop a tough, impact and abrasion resistant coating for erosion protection of wind turbine blades. The coating was to be suitable for Polymer Thermal Spray (PTS) deposition over new and existent wind turbine blades. Furthermore, the material had to be suitable for thermal deposition at temperatures significantly lower than the thermal degradation temperature of the fiber-reinforced-polymer (FRP) substrate. In addition, the coating had to pass harsh rain erosion tests, both in-house and at a specialized laboratory. Finally, the coating material was to be deposited without issues over an 8.3m long BSDS (Blade System Design Studies) blade donated to Resodyn by Sandia National Laboratories (SNL) and National Renewable Energy Laboratories NREL. All objectives of this Phase I feasibility study were successfully accomplished in full. The prototype coating selected for Phase II developments was subjected to a wide range of tests during the Phase I technical feasibility study. The following paragraphs present some of the most important characteristics of the selected prototype material, as resulted from Phase I testing: The prototype coating performed very well in rain erosion tests conducted for 20hrs at a specialized laboratory at tip speeds of 125m/s. In rain erosion tests conducted in-house per ASTM G73 at tip speeds of 76m/s, the prototype coating significantly outperformed commercial benchmark products employed for leading edge protection. Such benchmarks included two urethane coatings and one urethane wind protective tape. The prototype coating was successfully PTS deposited over the leading edge of an 8.3m-long BSDS blade obtained from Sandia National Labs / National Renewable Energy Labs (SNL/NREL). In sand erosion tests conducted in-house the prototype coating significantly outperformed the three commercial benchmark products employed for leading edge protection. The prototype coating passed 30 cycles of harsh thermal shock testing without any cracking or delamination. The prototype coating passed harsh accelerated UV exposure tests conducted for periods in excess of 1,700hrs, in accordance to ASTM G154. The prototype coating passed harsh flexibility tests in accordance with ASTM D522 without any cracking or delamination. The prototype coating passed harsh impact tests in accordance with ASTM D5420 without any cracking, delamination or other types of failures. The prototype coating passed harsh gravel impact tests in accordance with ASTM D3170 without any cracking, flaking or coating removal. The prototype coating passed Taber abrasion tests in accordance with ASTM D4060, exhibiting mass loss values significantly lower than the benchmarks. When PTS deposited on fiber-reinforced-polymer (FRP) specimens from a leading blade manufacturer, the prototype coating passed harsh adhesion tests in accordance with ASTM D4541, ASTM D3167 and ASTM D3359. The customer that Resodyn will pursue with the proposed product innovation is in essence the wind-power industry. More specifically, the key customers targeted by this innovation will be aftermarket, service-provider companies and original equipment manufacturer (OEM) wind-turbine companies. Resodyn is already in discussions with important aftermarket service-providers and OEM companies.

• Research Organization: RESODYN CORPORATION
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: SC0017698
• OSTI ID: 1457138
• Type / Phase: SBIR (Phase I)
• Report Number(s): DOE-RESODYN-17698-1
• Country of Publication: United States
• Language: English