The LEFT project (Leading Edge for Turbines) with Radius Aerospace UK Ltd and Performance Engineered Solutions Ltd has investigated the use of nickel-cobalt (Ni-Co) erosion shields for blades. The project has shown that the Ni-Co solution is capable of far greater tip speeds than those currently used in industry – perhaps as high as 120m/s.
The tip speed of wind turbines is determined by several factors – noise, leading edge erosion, and aero-elastic stability. Onshore, noise has generally been the limiting factor, so erosion has not been such a large problem. However, offshore, where this noise element is removed, erosion has been the limiting factor. If this Ni-Co solution can shield the blade and allow the tip speed to be increased to 120m/s then the size of the nacelle can be substantially reduced. This reduction in nacelle mass could lead to follow on benefits for the mass of the support structure, ultimately turbine capital costs could decrease by 15-20%.
As part of the study investigating technologies which may enable 20MW floating wind, ORE Catapult is working with CFD experts Anakata Wind Power Resources Ltd, to develop an aerofoil family and blade geometry which will be suitable for these ultra-high tip speeds.
An optimised structural design that will withstand the aerodynamic loading generated by this new blade geometry will then be created using Bristol University’s ATOM software and analysed for its cost of energy. The software can also capture follow on benefits of a turbine design to the tower and foundations.
ORE Catapult has developed methods of estimating the nacelle mass on the basis of the rated torque, and design optimisers for the tower and floater to help us understand how much the tower mass can be reduced as a direct result of the lower top head mass. They have also been responsible for coordinating the other project partners on this element of the project.
The results of this feasibility study will determine if the high tip speed design variant is a suitable enabling technology for large scale (>20MW) future turbines.
