Research On Aerodynamic Performance Of MW-class Wind Turbines With Winglets

As the turmoil in Russia and Ukraine intensifies,energy security has once again entered the public eye.In order to change my country’s long-term dependence on energy imports and ensure my country’s energy security,the development and utilization of new energy has become the focus.In China,wind resources are widely distributed and reserves are large,and how to efficiently utilize wind resources has become the top priority.Wind turbines are the key to the efficient use of wind resources.Due to the existence of the tip vortex generated by the tip effect,the torque of the wind turbine is reduced.The blade tip winglet can increase the power of the wind turbine,and it can control the tip vortex developed in a spiral shape at the tip of the blade,thereby improving the aerodynamic characteristics of the wind turbine.In order to study the relationship between different tip winglet configurations and the changes in the aerodynamic performance of wind turbines,the following scientific research work has been carried out in this paper:Using different computational fluid dynamics methods,the aerodynamic performance of the NREL Phase VI wind turbine was calculated and compared with the wind tunnel experimental results of the NREL Phase VI wind turbine in the literature,which confirmed the high reliability of the Reynolds average simulation method.The aerodynamic performance of the NREL 5MW wind turbine is calculated by the Reynolds average simulation method,and the calculation results of other solvers are compared to verify the accuracy of the method again.Select two important winglet configuration parameters and define them,determine the winglet segment from 62 m to 63 m,and do not change the swept area of the wind rotor,take 5 test values for the two configuration parameters,and set up a total of 25 groups Experiments were carried out,and the aerodynamic data of 25 wind turbines with winglet configurations at different wind speeds were obtained using the calculation method determined in this paper.The range analysis and variance analysis were performed on the obtained data to study the relationship between 25 winglet configurations and the changes in the aerodynamic performance of the wind turbine,and the priority and significance of the two configuration parameters were obtained,proving a reasonable winglet The configuration can have a positive effect on the aerodynamic performance of the wind turbine,and find the optimal winglet configuration under different wind speeds.The wind speed sensitivity analysis was carried out,and the S18 winglet configuration was obtained as the most ideal winglet configuration.Among the 25 winglet configurations,S18 was selected as the most typical suction surface swept-back winglet configuration,and the power augmentation mechanism of this winglet configuration was studied.Analysis of the tip flow field of the wind turbine shows that the tip vortex generated and developed from the x/c=0.8section has a great influence on the tip flow field.The influence range of the tip vortex accounts for less than 3% of the total length of the blade.By comparing the pressure distribution of the tip suction surface,the static pressure coefficient of the tip vortex and the tip vortex vortex field,it can be seen that the tip vortex can control the influence range of the tip vortex,limit the strength of the tip vortex,and accelerate the dissipation of the tip vortex.Comparing each velocity cloud map in the wake region,the tip winglets can speed up the speed dissipation in the wake region,reduce the influence range of the wake region,and increase the output power of the wind turbines in the entire wind farm,thereby improving the economic benefits of the wind farm.This paper conducts an in-depth study on the relationship between various winglet configurations and the change of wind turbine aerodynamic performance,analyzes the influence of various winglet configurations on the torque and thrust of wind turbines,and expounds the power augmentation of blade tip winglets.It also revealed the adjustment effect of the tip winglet on the tip vortex,which provided a certain reference for the final application of the tip winglet in the product.