Research On Noise Evolution Mechanism Of Small Wind Turbine Under Icing

With the increasing capacity of wind turbine assembly and the increasing scale of wind power market,it has become one of the most commercial and promising power generation methods in the renewable field.The Inner Mongolia Autonomous Region is rich in wind energy resources,but due to the cold climate,extremely low climate in winter and spring,rain and snow weather will cause wind turbine blade icing,which will bring a series of problems,serious may lead to blade damage or even the collapse of the whole wind turbine.Therefore,when the wind turbine icing accident occurs,the wind farm can only be forced to shut down for maintenance,which has a serious impact on the economic benefits and safe operation of the wind power industry.In order to ensure the stable operation of wind turbine in low-temperature and humid areas,this thesis studies 1kw small wind turbine.Through the research on the noise evolution mechanism of small wind turbine under different working conditions,the noise evolution law under different working conditions and the primary and secondary order of the influence of different icing factors on noise are found(1)The wind wheel of 1kw small wind turbine is modeled by Faro edge 3D scanner,and the two-way fluid solid coupling simulation of wind turbine is carried out by using ANSYS Workbench platform.The results show that with the increase of icing mass,the fluctuating pressure on the blade tip near the leading edge changes sharply.It is obvious that there are vortices gathering here,and the gathering and splitting of vortices are the main sources of noise.It can be seen from the axial vorticity diagram that the size and number of vortices after icing are significantly larger than those without icing,and when the icing mass reaches 0.75 kg,the turbulence degree of flow field at the tail of the wind turbine is more obvious.(2)The results show that the aerodynamic noise of each measuring point increases obviously with the increase of icing thickness.However,the corresponding frequency of the peak is basically unchanged.It can be seen from the power spectrum that the energy is mainly concentrated in the fundamental frequency,the first harmonic,the second harmonic and the third harmonic.The energy at the fundamental frequency is the largest,and the sound pressure level will increase with the increase of the speed.(3)Comparing the test and simulation results under different working conditions,the frequency of each measuring point is basically the same at the fundamental frequency and multiple frequency,and the sound pressure level obtained from the test is greater than that from the simulation.The sound pressure level reaches the maximum at the reference position.Through the noise source test,with the increase of icing mass,the sound pressure level near the leading edge of the blade tip is larger,which indicates that the noise source position of the wind turbine is kept at 0.5r-0.85 r.