STRUCTURAL DESIGN AND EXPERIMENTAL INVESTIGATIONS OF A SHAPE-ADAPTIVE SLAT FOR WIND ENERGY ROTOR BLADES

Kurzfassung

The trend towards larger rotor blades is still continuing, since the generated electrical power is proportional to the square of the blade length. However increasing rotor blade length will also increase the blades weight by the radius cube. Consequently mass induced loads such as centrifugal loads also increase. In addition larger blades lead to increased dynamic blade loads induced by vertical wind gradients and turbulent inflow conditions. A morphing slat that allows a dynamic gap variation between the slat’s railing edge and the main profile offers a great opportunity to reduce such fatigue loads. In order to show the proof of concept of such a shape-adaptive slat, a wind tunnel experiment was designed and executed. This paper presents the development of the shape-adaptive slat in wind tunnel scale. In order to ensure the fatigue behaviour a parameter study for the slat’s design is done. The bjective is to avoid a concentrated local strain maximum in the case of the deformed slat. As a next step, six slat segments are manufactured to investigate the deformation behaviour and to validate the simulations in a static experiment. The same segments are used to perform long-term fatigue investigations with dynamic slat deformations. Based on the experimental results a heat treated steel is selected to manufacture the final wind tunnel slat.