Research On Aerodynamic Loads And Wake Flow Fields Of Wind Turbines

With the rapid development of the massive utilization of wing energy, the problems of the wind turbine groups have been brought into the focus recently. The interactions of the aerodynamic loads and wake flow fields of the wind turbines, become the premises of the optimization and the performance predictions of the wind farm. The problems not only impact the wind turbines efficiency and the power network dispatching, but also threaten the lifetime and the safety of the wind turbines. Therefore, the object of the thesis is the numerical methods for the aerodynamic loads and wake flow fields of the single wind turbine based on vortex theory, and the goal is the faster and more accurate methods for the bases of the research of the performance predictions and the wake interactions in wind farm.It is deeply researched that the principles and numerical procedures of the lifting line theory, lifting surface theory and panel method. First of all, the aerodynamic loads of the wings and the blades of NREL PHASE VI are calculated by the programs which are based on the lifting line model and the explicit KUTTA conditional vortex lattice model. The results are compared and analyzed. And then, the aerodynamic loads of the airfoils, the wings and the blades of NREL PHASE VI, are calculated by the programs which are based on the 2D and 3D HESS-SMITH panel methods, and the results are compared and analyzed. At last, the wake flow fields of wind turbine are calculated by the 3D HESS-SMITH panel methods in near and far area.In conclusion, the panel method is more precise than the lifting line method and the vortex lattice method in the domain of the flow fields calculating of the wind turbine. Different from the blade element momentum (BEM) theory, the panel method can solve the pressure coefficient distribution in blade surface and the wake flow fields, and the method can calculate any geometry of the blade. Compared with the computational fluid dynamics (CFD) method, the panel method is a higher efficiency and lower cost method. Based on the HESS-SMITH panel method, the conclusions can be used as technical supports for the flow fields calculation and the performance prediction of wind turbine groups.