What do Shark Fins, Winglets and Turbulators Have in Common?
Ambitions and developments in offshore wind energy have forced us to re-evaluate our approach and methods in wind turbine blade design once more. With the ultimate goal of reducing the levelised cost of energy (LCoE) through optimised tip design, the InnoTip research project ran as a collaboration between LM Wind Power’s aerodynamics team and ECN. During this project three new tip designs were delivered and two were tested by extending the blades on ECN’s 2.5MW test turbines with a temporary add-on tip extension – a unique process.
By Ozlem Ceyhan Yilmaz, ECN, The Netherlands and Jordy van Kalken, LM Wind Power, Denmark
Project Overview and Motivation
Because of the differences between onshore and offshore operating conditions and constraints, the tip region of the blades for offshore turbines should be designed differently to obtain more power. In this research project, three different tip configurations were investigated. These were then designed and manufactured to be tested on LM 38.8-metre blades on the 2.5MW test turbines at ECN’s wind turbine test site (EWTW). It was quite a challenge to equip operating wind turbines with blade tip extensions for a limited period of time. However, the experiments were successfully completed and valuable data was collected. With the implementation of new tips, the measurement data showed an average of 6% power increase below rated speed, which was higher than the expectations. The results of this project prove that there is significant power enhancement potential when the tips of offshore wind turbine blades are designed differently.
