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Design and prototype production of a windturbine rotorblade for the 46-50 m diameter class


Project objectives

The project concerns the design, prototype production, laboratory testing and field testing of a windturbine rotor in the 46-50 m diameter range or even bigger. The special design features are a low weight blade, reduced tower trust and minimized noise emission. A test blade will be built to be laboratory tested, static as well as in fatigue at RISØ. A test set will be built to do a field test on a commercial Nordtank windturbine. During the field test loads, noise and power will be measured.

Technical approach

A new Delft University DU95-W-180 cross section will be chosen together with the well known DU25 sections. These cross sections combine a desired thick cross section with aerodynamic desirable properties such as high lift to drag ratio and reduced sensitivity for nose roughness.

The special airfoil was designed and windtunnel tested for lift over drag ratios of at least 130 at the design Reynolds number of 3.0 * 106. To reduce peak loads the maximum lift coefficient is around 1.25.
With the ECN computer code Bladeopt, the blade geometry will be generated. This code optimizes the blade geometry for maximum annual yield and lowest tower trust. With the FOCUS computer codes the structural blade design will be made. The structure and materials will be based on the standard Rotorline production method with fibre-glass polyester.
One blade will be built for laboratory strength testing at RISØ. Successively a field test on a turbine will be performed to measure the power curve, loads and noise emission.

Expected achievement and exploitation

The blade should have an annual output of a least 1250 Wh/m2 aerodynamically in a wind class II climate. For a 50 m diameter rotor this gives an aerodynamic annual yield of 2.45 Gwh.
The structural rotorblade weight should be less than 3.7 kg per m2 area, thus reducing turbine loads and blade costs. A 50 m diameter blade would weigh about 2400 kg for a bladed rotor.
The blade is expected to become commercially available at the beginning of 1998.


Rotorline The Blade Company B.V.
6,Stevinstraat 6
1704 RN Heerhugowaard

Participants (2)

Risø National Laboratory

4000 Roskilde
8444 Balle