Fluid-solid Coupling Analysis Of Composite Wind Turbine Blades

During the operation of the wind turbine,the blade is tend to deformation affected by the surrounding flow field.This deformation will also change the flow field.The interaction between the fluid and the solid has a great effect on the normal operation of the wind turbine.Therefore,it is of great importance to analyze the fluid-structure coupling problem of wind turbine blades.This paper uses UG software to construct geometry model of blades and wind rotor of 2WM wind turbine,in view of the layer order put forward a set of layer scheme,to set up the finite element model of blades and rotor and verify its rationality.On this basis,the flow field characteristics and vibration characteristics of blades and wind rotors are studied.This article has done the following work:l.Obtain the NACA4412 airfoil coordinates point data by Profili.According to the 3D coordinate transformation formula,the 2D coordinates can be converted to 3D coordinate points,and import the three-dimensional modeling software UG.The geometrical model of the blade and the wind rotor is formed by dot to line,line to the plane.2.The layer scheme is proposed for the stacking sequence,and the layer is carried out on the front and rear edges,roots and webs of the blades.According to the Cai-wu strength discriminant and the analysis of the finite element calculation results,to verify the rationality of the blade layer design.Results show that the value of Cai-wu strength discriminant from blade material is less than 1,the error of finite element calculation results and the simplified calculation results is less than 1%,the natural frequency is close to the reference value.The layer blade maximum stress value is less than the initial blade max stress value,verified the rationality of the layer blades.3.On the basis of deep understanding of fluid-structure coupling theory,to simulate the flow field of the motionless single blade and the rotating wind turbine,and the wind pressure distribution on the blade and wind rotor surface of the wind turbine is studied.The stress distribution and deformation of wind turbine blade and wind rotor are studied through static structure analysis.The results show that under the numerical simulation of the rated wind speed,blade tip is the most stressful part,where thickness is the smallest,and the position of the middle of the blade near the front blade is the maximum stress place.4.On the basis of statics analysis,Ansys Workbench is used to analyze the unprestressed and prestressed modal analysis of wind rotor under rotation.The vibration frequency of wind turbine in six specific working conditions is simulated.Results show that the swing and shimmy is main vibration form of wind turbines,the value of blade vibration frequency under six working conditions and natural frequency value under the condition without prestressed are basically the same,wind pressure prestressed basically will not affect rotor vibration frequency,and the effects of rotation prestressed on the rotor vibration frequency is great.