Investigations for Improvement of Energy Yield of Rotor-blades from the 1.5 MW Class

In a combined approach of extensive measurement and accompanying simulation a wind turbine blade used in the 1.5 MW class was investigated for improvement of aerodynamic properties and especially the energy yield. One blade was dismantled and its geometry was locally measured by a specially designed laser scanning-system. From this geometry data set five 2D wind tunnel models were manufactured and measured in the wind tunnel of Deutsche Wind Guard Engineering GmbH at Bremerhaven, Germany. In addition, extensive CFD investigations were performed to investigate the usefulness of so-called aerodynamic devices like vortex generators, Gurney flaps and others for improving energy yield. As a result it could be shown that the aerodynamic efficiency of the manufactured blades - if measured in terms of lift-to-drag ratio - is at a high level but still can be further improved. 3D CFD investigations were able to show the influence of Gurney flaps and boundary layer fences and their interactions.