Research On The Fluid-Structure Coupling Characteristics Of Large-Scale Flexible Blade Wind Turbine

In recent years,wind power generation has developed rapidly in my country,and the proportion of wind energy in my country’s energy structure has increased year by year.More and more wind turbines have been installed and put into operation.The research on wind turbines has also received extensive attention from scholars at home and abroad.The problem becomes even more important as wind turbines become larger in size.In this paper,the NREL5 MW wind turbine is taken as the object,and the numerical simulation method of fluidstructure coupling is used to discuss the aerodynamic and aeroelastic problems of the wind turbine in the wind field under different working conditions,especially the structural response of the wind turbine blades with different structures.system Research.The main work is as follows:First,this paper introduces the basic theory of wind turbines and the current research status at home and abroad,and then introduces the basic theory of fluid-solid coupling and other basic theories.On this basis,follow-up work is carried out.In the third chapter,the CFD numerical simulation of the wind turbine in different working conditions is carried out,and the aerodynamic load of the wind turbine is verified and studied.The distribution characteristics of aerodynamic loads and the effect of shear flow on aerodynamic loads are studied.Secondly,the wind turbine is numerically simulated using two coupling modes of oneway and two-way fluid-structure coupling,and the differences between different coupling modes are compared and studied from the aspects of aerodynamic load,flow field characteristics,coupling deformation and equivalent stress-strain distribution.It is found that because the one-way coupling does not consider the influence of structural deformation on the fluid,the aerodynamic load is larger than the solution result of the two-way coupling,and the result of the two-way coupling is closer to the experimental data released by the NREL laboratory.The two-way fluid-structure coupling can simulate the state of the wind turbine at each moment.Comparing the results of the one-way coupling,it can be clearly found that the more dangerous state in the middle moment,the two-way coupling is obviously better than the one-way coupling.Finally,two-way fluid-structure interaction simulations are carried out for wind turbines with blades with different internal structures.It is found that the maximum equivalent stress and strain of the wind turbine model of the beam structure blade are distributed in the middle part of the blade near the leading edge,while the maximum equivalent stress and strain of the wind turbine model of the shell structure blade are distributed near the leading edge of the blade root airfoil,and the dangerous area is significantly smaller than Beam model wind turbine.The coupled deformation of the wind turbine model with a shell structure blade with a web is significantly reduced,and the equivalent stress and strain distribution of the skin are similar to those of the shell structure,but the numerical value and the maximum equivalent stress distribution area are significantly smaller.From the comparison of the three,the shell structure blade with web is the best.In this paper,the aerodynamic and aeroelastic characteristics of the wind turbine under different working conditions are obtained by CFD simulation and fluid-structure coupling simulation of the NREL 5MW wind turbine,which provides a reference for the design and safe operation of wind turbine blades.