Research On Simulation And Control Strategy Aerodynamic Noise Of Large Scale Wind Turbine

With the relatively rich wind power resources and the rapid economic growth of the central and coastal areas in China,wind farms are getting closer and closer to residential areas,causing residents to complain about wind farm noise gradually.The problem of aerodynamic noise of wind turbine has attracted much attention.Based on computational fluid dynamics and computational acoustics,numerical simulation analysis of flow field and sound field of a large 2MW wind turbine and its airfoil were carried out.The field test experiment of the aerodynamic noise of the wind turbine was carried out in the wind farm.The results show that:(1)The maximum aerodynamic noise of wind turbine at rated wind speed is 132dB,which is mainly distributed in the position of 0.1R-0.9R.The aerodynamic noise of impeller surface attenuates and diffuses in a circular direction.The ground aerodynamic noise attenuates and diffuses in a circular direction and the maximum aerodynamic noise in the center of the ground is 70.8 dB.The aerodynamic noise of the vertical plane attenuates and diffuses in the surrounding direction with the dipole characteristic.There are two high pressure noise regions in the center of the impeller in the range of 10-50m,with a maximum value of 118dB.The field measurement results of wind farm show that the maximum error between the ground measured value and the ground simulated value is 4.23%.(2)The aerodynamic noise of the airfoil on the longitudinal and transverse planes attenuates and diffuses in a dipole direction,while the aerodynamic noise in the horizontal plane attenuates and diffuses in a circular direction.The aerodynamic noise of airfoil increases with the increase of attack angle and relative wind speed.When the angle of attack increases from 5°to 11°,the aerodynamic noise increases 6.13%at the edge of 5m in the longitudinal plane of the airfoil,and the average attenuation rate of aerodynamic noise of the airfoil is 10.96dB/m in the range of 0?5m.When the relative wind speed increases from 25m/s to 40m/s,the increase of aerodynamic noise is 5.98%at the center of the longitudinal plane and 13.61%at the edge of 5m,and the average attenuation rate of aerodynamic noise is 11.23dB/m in the range of 0-5m.(3)The maximum aerodynamic noise of the four different tail flanges at the center is similar.In overall,the aerodynamic noise from small to large is:triangular trailing edge airfoil,blunt trailing edge airfoil,semicircular trailing edge airfoil and the sharp-tailed airfoil.And the aerodynamic noise of the triangular trailing edge airfoil is 5.07%lower than that of the blunt trailing edge airfoil before unreformed,which can provide a theoretical basis for wind turbine noise reduction control.