| Wind power is a green,low-carbon and environmentally friendly new energy source.However,wind turbines are often affected by harsh conditions such as dust,moisture,gravel and high wind speed.What's more,wind turbine blades are susceptible to the periodic aerodynamic,which results in blade vibration.It not only reduces the service life of the blades but also poses a safety hazard.Therefore,based on wind turbine aerodynamics and fluid-solid coupling theory,the fluid-solid coupling calculation of wind turbine was carried out at different wind speed,angle of attack and material.The modal characteristics of blades,flow field characteristics and vibration displacement variation rules were obtained.It provided references for the stable operation of wind turbines and the further development of wind power generation.The main work and results of this study are as follows:1.The effectiveness of the fluid-solid coupling method used in this study was verified.Based on the variation trend of pressure coefficients in numerical examples of circular cylinder flow at different wind speeds,it was found that the variation trend of two pressure coefficients curves was similar and the separation points were about 80°.The torque,power and section pressure coefficient of the steady flow field were obtained by ANSYS software and were compared with the experimental values of wind tunnel.The overall comparison was consistent.But the power and torque were obtained in the range of 10~20 m/s and the pressure coefficient of 30% section was slightly higher when the wind speed was 10m/s,which was affected by stall delay.Finally,the-SSTk ? turbulence model was used to verify the two-way fluid-solid coupling of the thin plate,and it was found that the vibration frequency,period and the displacement change trend in the free end of the plate were in good agreement with the experimental values.2.Fluid-solid coupling analysis of wind turbine single blade was studied.Under the wind speed of 15~50m/s,the k-? turbulence model was used to simulate the single-blade two-way fluid-solid coupling.The Y-direction vibration displacement cloud chart of the suction surface showed that the maximum vibration displacement was generated at the tip of the blade.The pressure cloud chart showed that the maximum pressure of the blade was distributed at the leading edge of the blade.The variation of the vibration displacement at different wind speeds showed that the maximum displacement was proportional to the wind speed and the amplitude was the smallest(0.5254 mm)when the flow velocity was 15 m/s.The vibration reached the maximum(4.7282 mm)when the flow velocity was 50 m /s,which is about 9.0 times of the minimum amplitude.3.Fluid-solid coupling analysis of wind turbine rotating double blades was studied.Under the combined conditions of different wind speeds(20 m/s,30 m/s,40 m/s and 50 m/s)and angles of attack(-5°,-3°,-1°,0°,1°,3° and 5°),the two-way fluid-solid coupling analysis of glass fiber blades by-SSTk ? turbulence model showed that the maximum vibration displacements at different wind speeds were 0.1432 m,0.2014 m,0.2932 m and 0.3464 m when the angle of attack was 0°.It was found that the larger the wind speed was,the more complex the flow phenomena were,the wider the area covered by the vortices was,and the more obvious the flow separation was.4.In order to improve the contrast,the two-way fluid-solid coupling analysis of carbon fiber blades was carried out under the same conditions.It was found that the maximum vibration displacements at different wind speeds were 0.0450 m,0.0636 m,0.0935 m and 0.1128 m at attack angle of 0°,which were 68.58%,68.42%,68.11% and 67.44% lower than that of fiber glass blade.Compared with glass fiber blades,carbon fiber exhibited better vibration damping performance,the high damping of the matrix and the existence of internal reinforcement filler made the vibration process consumed energy quickly.The macroscopic performance was that the vibration displacement of the blade decreased,which in turn reduced the possibility of blade damage,and the employment of carbon fiber materials could effectively extend the service life of safe operation.The reasonable selection of material for wind turbine blade could effectively reduce the blade vibration displacement,increased the service life of the wind turbine for stable power output and safe operation.It was conducive to the further development of wind power technology.Figure [39] Table [8] Reference [71]... |
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