Project title: Leading Edge Erosion of Wind Turbine Blades

Lead Research Organisation: University of Sheffield
Department Name: Mechanical Engineering


Aims and objectives:

1. Conduct a comprehensive review of existing scientific literature to gain a broad understanding of the erosion of wind turbine blades
2. Identify any gaps in existing research
3. Gather data on typical wind turbine blade geometries, materials, and operating conditions
4. Design and develop an experimental rig capable of accelerated erosion testing of wind turbine blade materials under realistic operating conditions
5. Gain a fundamental understanding of the erosion of composites and polymers in the context of wind turbines using experimental tests
6. Investigate the effects of different erodents, both solids and liquids, on wind turbine blades

Applications and benefits:

Wind turbines can be found all over the world, and their operating environment varies wildly depending on their location. Moreover, as bigger and more powerful turbines are built, increasingly they have expanded into more remote and extreme environments. Among these, three distinct climatic zones are emerging: icy Nordic environments, humid regions with a large insect population, and deserts with sand-laden winds. Thus, ice adhesion and accumulation, insect accumulation, and erosion by sand and water droplets have been cited as the three biggest current challenges in blade surface engineering. However, erosion may also be caused by other airborne particles including hailstone and dust, and influenced by factors including UV radiation and moisture/humidity.

Images from field operation show that the effects of leading-edge erosion can become a visible issue after just one year in service. After ten years, erosion can penetrate the surface coating and present a severe problem. Considering wind projects are normally designed with an assumed operational lifetime of 20-25 years, the protection of the leading edge against erosion is clearly critical.

Leading edge erosion can be hugely detrimental to the aerodynamic efficiency of the blade, and hence lead to significant loss in the turbine's annual energy production (AEP) and in turn its profitability. Studies have shown that, depending on the level of leading-edge erosion, the drag of the aerofoil can increase by 6-500%. For many of the moderate-to-heavy erosion cases, drag increases of 400-500% coupled with a loss in lift led to a reduction in AEP of up to around 25%.

Erosion of the blade can also directly impact the material integrity and therefore its operational lifetime. Any removal of the surface coating could mean that the composite substrate itself is susceptible to higher rates of erosion, which can affect the structural integrity of the blade itself. Through-thickness erosion would be particularly problematic if particulates and liquid droplets enter the internal blade structure.

To address these challenges presented by both solid and liquid particles erosion, many companies and manufacturers are now working on new materials and coatings for wind turbine blades. Reliable accelerated erosion testing is crucial in the development of these materials in order to understand their effectiveness against different erodents. However, there are currently few wind turbine-specific test methods available, especially one that is able to test resistance against both solid and liquid erodents. The new erosion rig to be developed as part of this project will aim to achieve just that.

Planned Impact

The impact of the Centre will be manifest itself in four ways; by the number and quality of skilled PhD graduates it produces, by the reach and significance of the research that is generated during their studies, by the contribution to the research base in tribology, and through the broader societal impact of improved machine efficiency and energy utilisation.

The number and quality of PhD graduates. iT-CDT plans, in the steady state, to graduate 12 PhD students per year. We expect these students to enter industry as research leaders or academia as RAs then lecturers. UK and EU industries are desperately short of PhD graduates, and they are in demand. We expect to have impact on UK industry with a stream of PhD graduates who will enter for example, the automotive sector (e.g. designing more fuel efficient engines), the rail sector (e.g. increasing network capacity and reducing cost through improved track and vehicle components), the oil industry (e.g. developing new lubricants for increased fuel efficiency), aerospace sector (e.g. tribology needs in jet engines), the power industries (e.g.developing and maintaining more efficient transmissions). PhD students may also commercialise technology or consultancy in the form of a spin-out activity. We have a track record of past PhD students achieving all these things. The iT-CDT plans to extend and broaden that record, will facilitate synergy across the discipline.

The transformative PhD research. During their studies, PhD students will be conducting research on an industry led project. These projects will also have elements of generic application therefore have wide impact. The students will be closely involved with both the sponsoring organisation and other industrial partners. This means that there will be a direct route for technology transfer.

Contribution to the Research Base in Tribology. The iT-CDT is a grouping of the two leading universities in tribology in the UK. It will form the largest critical mass of academics, RAs, and PhD students in the EU. A team of industrial partners will steer the research so that it is relevant and has real routes to impact. This platform will lead to a growth in the research base in tribology for the UK and will impact both industry, with improved products and processes, and academia with the supply of new technology and analytical methods.

Societal Impact. The development of new tribological processes, and engineers skilled in their conception and implementation, will have broader societal impact with machines and process that run with lower friction, higher energy efficiency and have greater durability. In the shorter term, we also plan as part of the iT-CDT for public engagement events using PhD students as the agents of delivery.



William Mai (Student)


10 25 50