Investigation of rotor. Preliminary investigation of rotor for 4 MW wind turbine

One code performs aeroelastic time domain simulations from which the loads and energy production are determined. The turbine is described by a number of design variables, which are optimized within some load constraints. From the design variables a cost price is estimated, which together with the annual energy production of the turbine forms a part of the objective function, which is minimized during the iterations in the optimization code. The other optimization code calculates the loads by semiempirical expressions for the blade root moments. One of the results derived from this project is the design of the 39 m blade for the V80 turbine. It has been investigated if current design principles and calculation models also are valid for larger wind turbines or if new unexpected phenomena occur. The calculation models have shown to be sufficiently good. However it is shown that the net weight of larger turbine blades gets so dominating that it is profitable to produce the blade of stronger and lighter materials. The possibility of using carbon fibres instead of glass fibres has been investigated and some essential problems with carbon design is discussed. According to the investigation the use of carbon fibres in larger blades will be profitable in the near future