Photo from Anna-Maria Tilg

Rain climate and erosion of wind turbine blades

The PhD thesis “Rain climate and erosion of wind turbine blades” links leading edge erosion of wind turbine blades and precipitation measurements. It interacts with the on-going project EROSION: Reducing the largest uncertainties (www.rain-erosion.dk).

Background 

Different environmental factors like precipitation or sand cause damage on the wind turbine blade. The damage starts at the leading edge with small pin holes and increases with time. The aerodynamic efficiency of the wind turbine blades decreases with increasing erosion as the roughness of the material increases. This results in a lower power production. To reduce erosion and associated costs, it is important to understand the causes of erosion in more detail. 

Objectives 

The first objective of the PhD project will be the analysis of disdrometer measurements in Voulund, a field site in Denmark. The Danish Meteorological Institute (DMI) will provide these data. A disdrometer measures the number, size and velocity of precipitation particles. The frequency and range of measured numbers, sizes, velocities and types of precipitation particles is elaborated. The most important part of this work is the calculation and analysis of the rainfall kinetic energy. Precipitation parameters will be compared with available wind speed measurements to investigate the correlation of intense precipitation events and high wind speeds. 

The second objective will be the comparison of precipitation parameters like rainfall kinetic energy of different sites located in Denmark and abroad with a focus on areas relevant for wind turbines. This comparison leads to a better global impression of the energy provided by precipitation. It is planned to use drop-size distributions (DSD) from sites on land and sea and should therefore help to improve the knowledge about similarities and differences of DSD onshore and offshore. There is only limited knowledge about DSD offshore. Therefore, disdrometers data from offshore environments measured in relation to the EROSION project will be used.  

For the third objective the use of precipitation measurements from weather radars and disdrometers for the so-called erosion-safe mode will be investigated. It is suggested to decelerate the rotation speed of the wind turbine blades during severe precipitation events to mitigate the erosion of the leading edges. However, it is unknown which sensor provides most reliable information for such turbine operation mode. 

Perspectives 

The PhD study helps to understand the influence of different precipitation climates on the erosion of wind turbine blades.

Contact

Anna-Maria Tilg
PhD student
DTU Wind Energy
+45 93 51 06 82