Numerical Simulation Of Horizontal Axis Wind Turbine Aerodynamic Performance And Tower Shadow Effect Research

As the development trend of wind turbine capacity of large-scale, the size of the windturbine is constantly expanding. Some problems that only influence the downwind typehorizontal axis wind turbine seriously are also gradually highlighted in the upwind typewind turbine, more outstanding is the tower shadow effect. This blocking effect of tower,can arouse a transient reduction of wind turbine aerodynamic load and a periodic loadimpact to the tower at the same time. This phenomena seriously affect the life and operationsafety of a wind turbine. Over the past ten years, the experiment method, the shadow modeland CFD method had been carried out to the study of the tower interference of downwindtype wind turbine and a lot of research results have been accumulated. But tower shadoweffect research is very few specifically for the upwind type wind turbineIn this thesis,3D unsteady simulation of NREL Phase VI turbine tower shadow effectis performed by CFD method. Fluent solver in combination with SST k-ω model is verifiedas a reliable and exact CFD method by NREL Phase VI aerodynamic performancenumerical simulation method validation studies. Then, different incoming wind velocities(7,13and20m/s) are selected for unsteady simulation with ICEM Hexa mesh.Computations are presented on an isolated rotor and the upwind configuration of theturbine which includes rotor and tower. The results show that an abrupt drop of torque andthrust can be observed around180°azimuthal angle by the influence of tower. A hysteresisof blade-tower interaction is also observed with the increasing of wind speed. Under thesame wind speed, the interaction decays along the spanwise of blade. Besides, theapplication of blunt trailing edge blade can improve the aerodynamic performance of windturbine, but can’t play a role in decreasing the tower shadow effect. In another optimizationcase, aerofoil tower has a little help on weakening the blade tower interaction, yet it is moreowe to the reduction of tower diameter. Finally, a scaled turbine(1:14) that will be used intower shadow wind tunnel experiment is manufactured and the experiment scheme isintroduced in detail.