Aerodynamic Simulation Of Wind Turbine Considering Meso-and Micro-scale Coupling Under Typhoon

Mesoscale typhoons are significantly different from monsoons in microturbulent structures,so it is difficult to effectively simulate the near earth wind field characteristics of typhoons through wind tunnel test or small scale CFD.Wind load is the control load of tower-blade coupling system design of large-scale wind turbine,especially under the action of strong typhoons the wind-induced damage of the wind turbine system often occurs.For example,when sanmei came ashore in 2006,22 of the 28 wind turbines in Zhejiang Cangnan wind power plant suffered partial and overall wind destruction.However,current wind turbine related design specifications all take monsoons as the target,it is not reasonable to apply it directly to wind turbine structures under the action of typhoons.In addition,the aerodynamic performance of wind turbines considering different stopping positions,yaw angles and pitch angles under typhoons is still blank at domestic and foreign.Therefore,it is of great engineering application value and theoretical significance to explore the aerodynamic performance of wind turbine system under complex working conditions.As a new generation of medium-scale and small-scale prediction models,WRF mode and CFD technology are the most widely used high resolution refined wind field prediction technology.In view of this,a mesoscale weather prediction model(WRF)based on the non-static equilibrium euler equation model was introduced to simulate parakeet typhoon with high spatial and temporal resolution.First of all,the vorticity and helicity,cumulative convective rainfall and time history of "Nuri" typhoon during its landing will be analyzed.Then,combined with the comparison between the simulated typhoon center path and the measured one,the validity of the medium-scale typhoon "Nuri" simulation will be verified.Taking 5MW horizontal axis wind turbine of a wind power plant in southeast coastal area of China as the object,based on the WRF simulations to get close to the ground three-dimensional wind field data,and combined with small scale CFD large eddy simulation technology,three dimensional unsteady numerical simulation will be carried out for different stopping positions of single rotating cycle of blades.On this basis,the average and fluctuating air pressure distributions on blade and tower surfaces will be compared and studied.The influence of the stopping position on the characteristics of the system and the vorticity distribution will be discussed,and the most unfavorable stopping position,yaw angle and pitch angle of the large-scale wind turbine system under the action of typhoon will be summarized.According to the simulation study,the mesoscale WRF model can effectively simulate the near-surface typhoon wind field,and the "Nuri" typhoon profile index is 0.118 based on the least squares fitting.The downscaling simulation method in this paper can effectively simulate the three-dimensional typhoon field of such a large-scale wind turbine system.The aerodynamic performance of the wind turbine system with different stopping positions,yaw angles and pitch angles under the action of typhoon was comprehensively analyzed.It was found that the stopping position of the blade had a significant impact on the aerodynamic performance of the wind turbine system.1)The presence of the blade would significantly interfere with the flow field around the tower,and the presence of the tower would also cause mutual interference to the blades.But the emergence of the yaw angle will weaken the interaction of blades and the tower,and yaw angle increases to 20 ° impact gradually weakened.2)In addition,the pitch angle has a weak influence on the aerodynamic performance of the tower,and only has a certain impact on the pressure distribution on the blade surface.3)Therefore,the most unfavorable stopping position and yaw angle of the wind turbine under typhoon are the working conditions T-1 and P-1 respectively,and the most favorable pitching Angle is F-3.In this paper,the aerodynamic performance of wind turbine system under complex working conditions is studied in detail in combination with meso-and micro-scale nesting technology.The research results can provide a basis for the design of large wind turbine system against strong typhoons.