Fluid-solid Coupling Analysis Of Blades Of Small Vertical Axis Wind Turbines

With the negative impact of industrialization has increased,wind energy as a clean energy source,has developed rapidly with its own advantages.Since the vertical axis wind turbine can accept all incoming wind without yaw to wind device.It can reduce structural complexity、increase wind energy utilization、the tip speed ratio of the vertical axis wind turbine is small and relatively low aerodynamic noise.Therefore,vertical axis wind turbines are more suitable for installation in areas with high turbulence such as cities.During the operation of the vertical axis wind turbine,the blade will deform and vibrate and blade deformation and vibration will affect the airflow in the flow field.Its interaction is a typical fluid-solid coupling problem.But,the coupling of vertical axis wind turbine blades under different tip speed ratios is limited by experimental technology and the research progress is slow.Based on this shortcoming,the thesis is based on the research results of predecessors through the fluid-structure coupling analysis of the blade 、 explore the aerodynamic performance and structural response of wind turbine blades at different tip speed ratios,The specific work of the article has the following points:1.The physical model used in the thesis is established based on the airfoil NACA0021,transform the two-dimensional airfoil coordinate parameters.Reasonably divide the internal space structure of the blade.Establish the internal support structure of the simulated blade.Assemble and integrate the internal structure of the blade.Completed the establishment of the convective fluid-solid coupling simulation blade and the whole machine model.The flow field is modeled according to the blade and the whole machine model.2.The accuracy of the established simulation model is verified,and the simulation calculation results of the model in the paper are compared with the experimental results.By comparing the calculated results of the simulation model with the experimental results.It can be seen that the fluctuation trend of each simulation curve can fit the experimental curve better.The fluctuation trend of the two result curves is basically the same and the maximum deviation is small,indicating that the CFD numerical simulation results in the article are reliable.It is close to the real result,which verifies the rationality of the built model and meshing.3.CFD simulation analysis of vertical axis wind turbine blade is carried out to study the surface pressure,structural stress change,stress deformation position and change rule of wind turbine blade under different tip speed ratio,and analyze the dominant load of wind turbine blade during rotation.The results show that as the tip speed ratio increases,the wind speed loss area of the wind turbine flow field increases The stress at the joint between the blade and the bracket is the largest,and the pressure on the blade and the position of the maximum pressure change with the change of the phase angle.With the increase of tip speed ratio,the vibration frequency of the wind turbine increases.Under the coupling effect of the blade and the surrounding flow field,the displacement of each monitoring point fluctuates up and down,and finally stabilizes.The stress,strain,displacement and deformation of wind turbine blades in the rotating state are mainly controlled by centrifugal load,and the aerodynamic load has little effect on it.Displacement and deformation of the blade mainly occur at the trailing edge of the blade.The displacement value of the trailing edge along the blade’s span in the 0-0.5H section first decreases and then increases.The force and deformation at the 0.5H-H section are the same as 0-0.5H.This analysis is very important for optimizing the structure of vertical axis wind turbine blades and improving the strength and service life of wind turbine blades.Accumulate experience for the standardization,parameterization and high efficiency research of vertical axis fans.