The Evaluation of the Wind Loads on a Wind Turbine under Different Wind Conditions

In recent years, green energy issues have become very popular, one of which is the application of wind energy. The power generated by the wind turbine is one important application of wind energy. However, some natural disasters, including earthquakes, could cause wind turbines to collapse and damage. Therefore, setting up the seismic standard of wind turbines becomes particularly important for safe design concerns. The focus of this research is to simulate the overall wind field around the NREL 5-MW wind turbine and predict its blade aerodynamic loads under different wind conditions by the CFD (Computational Fluid Dynamics) package software, ANSYS Fluent. The MRF (Multiple Reference Frame) and sliding-mesh methods were employed to simulate the rotation of fan blades until the periodic state. According to the standard IEC 61400-1 established by the International Electrotechnical Commission ( IEC), the effects of the wind speed profile, wind speed duration, and turbulence intensity of each wind condition on the two drag coefficients in the two horizontal directions and torsional wind coefficient were investigated to assess the feasibility of the wind turbine structure. Based on the CFD results, it is found that the wall shear stress on the fan blades increased with height. Therefore, when designing the fan blades, it is necessary to strengthen the wheel valley to stabilize the structure of the fan blades.