Abstract
The size of wind turbine rotors is still rapidly increasing, though many technical challenges emerge. Novel rotor designs emerge to satisfy this up-scale trend, such as downwind load-aligned concepts, which orients the loads along the blade spanwise to greatly decrease the bending moments at the root. As the studies on the aerodynamics of these rotor concepts using 3D body-fitted mesh are very limited, this paper establishes different cone configurations based on the DTU 10 MW reference rotor and conducts a series of simulations. It is found that the cone angle and the distance from the blade section to the tip vortex are two deterministic factors on conning. Upwind rotors have larger power output, less thrust, smaller wake deficit, and smaller influencing area than downwind rotors of the same size, which provides superior aerodynamic priority and benefits wind farm design. The largest upwind cone angle of 14.03°, among the cases studied, leads to the highest torque to thrust ratio which is 3.63% higher than the baseline rotor. The downwind load-aligned rotor, designed to reduce the blade root bending moments at large wind speed, performs worse at the present simulation conditions than an upwind rotor of the same size.
Highlights
Wind energy is an important renewable energy source
They found that the bending of the blade tip out of the plane can influence the aerodynamic of the whole blade, which is similar to the findings mentioned above
Special coning, bending, or winglet configurations may play an important role in the design of the next-generation super-large wind turbines
Summary
Wind energy is an important renewable energy source. On one side, the number of wind turbines has significantly increased year by year since the 1970s [1]. From an optimization study of a 5 MW wind turbine rotor [6], it was found that the maximum tip Energies 2020, 13, x FOR PEER REVIEW displacement or rigidity of blade constrains the further reduction of blade mass, which implies the significance of larger tip-tower clearance. Measures or designs, such assuch coned, pre-bending the significance of larger tip-tower clearance. [15] proposed a method to design the pre-bending the using blade one-way fluid-structure interaction.
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