Reliability Analysis And Research Of Vertical Axis Wind Turbine Impeller

Affected by the global governance situation of climate change,people ’s demand for building eco-friendly development and green low-carbon society is becoming more and more urgent.Globally,a new round of energy revolution centered on the concept of " low carbonization and no carbonization " is booming.The world ’s energy development is gradually moving from high-carbon energy to low-carbon energy and from fossil energy to non-fossil energy.As a clean power generation technology that promotes the optimization of energy structure,wind power generation has achieved large-scale development and application worldwide.Vertical axis wind turbines are widely installed in urban living areas and remote areas of agricultural and pastoral areas due to their economic structure,uniform wind,convenient maintenance and low noise.It can improve the local consumption of wind power,alleviate urban haze and solve the problem of power supply in remote areas.In view of the inconvenience of electricity consumption in remote areas,agricultural and pastoral areas and the reality of large electricity consumption in urban areas,this paper considers the uncertainty of wind load in different time and airspace caused by factors such as environment,region,latitude and time,which is easy to cause the wind energy utilization rate of wind turbine impeller to decrease and the reliability of wind turbine to be insufficient.Based on the theory of computational aerodynamics,the three-dimensional model and finite element model of wind turbine impeller are established.The spatial and temporal characteristics of wind speed distribution are integrated.The wind speed data are re-analyzed and re-analyzed,and the wind speed distribution model with spatial and temporal characteristics is established.Combined with the spatial and temporal characteristics of wind speed distribution,the aerodynamic characteristics,load characteristics and force characteristics of wind turbine impeller are analyzed.The wind energy utilization rate of wind turbine impeller fusion time-space domain is improved,and the reliability of wind turbine impeller fusion time-space domain is verified.The main research contents and conclusions are as follows:(1)Wind speed uncertainty analysis of wind turbines in time-space domain.Three wind speed probability distribution models of single-parameter Rayleigh distribution,twoparameter Weibull distribution and three-parameter generalized extreme value distribution are estimated by moment estimation method,least square method,maximum likelihood method and power density method.Five goodness-of-fit indexes of error square sum,root mean square error,K-S check,determination coefficient and residual standard deviation were used to test the goodness-of-fit of wind speed probability distribution model,and the wind speed probability distribution model and function of the two stations were determined.The results show that the normal distribution is not suitable for fitting the wind speed probability distribution of stations with skewness and kurtosis not zero.The two-parameter Weibull distribution estimated by the least square method is not suitable for fitting the wind speed probability model,especially in wind speed concentrated areas.The threeparameter generalized extreme value distribution has good applicability and accuracy.The maximum likelihood estimation method has high accuracy.(2)Research on numerical simulation method of vertical axis wind turbine impeller.Combined with computational aerodynamic theory,Bates theory and blade element theory,the three-dimensional model of wind turbine impeller is established by Solidworks,and the finite element model of wind turbine impeller is established by ANSYS ICEM CFD,ANSYS Fluent and ANSYS Structural software.The numerical simulation method is used to verify the independence of rotation period,the independence of mesh number and the independence of step size on the Workbench platform,which proves the economy and availability of the numerical simulation model in this paper.Compared with the wind tunnel experimental data,the reliability of the numerical simulation analysis is proved.(3)Research on reliability of vertical axis wind turbine in fusion time-space domain.The Workbench platform is used to analyze the aerodynamic characteristics,load characteristics and force characteristics of the vertical axis wind turbine impeller in the fusion time-space domain by using the one-way fluid-solid coupling numerical analysis method.Combined with the p-S-N curve of LY12 CZ aluminum alloy,the reliability of the vertical axis wind turbine impeller in the fusion time-space domain is studied.The results show that the optimal tip speed ratio of the vertical axis wind turbine impeller is not only determined by the airfoil,but also slightly different under different wind speeds.High incoming wind speed can make the wind turbine impeller obtain better starting performance and aerodynamic performance,and higher wind speed can obtain better aerodynamic characteristics in the downwind area than low wind speed.Increasing the number of blades can effectively improve the utilization rate of wind energy,and reducing the occurrence of stall phenomenon is an effective way to improve the utilization rate of wind energy of wind turbine.Selecting the appropriate rotor radius can effectively reduce the influence of blade wake in the upper wind area on the aerodynamic performance of blades in the lower wind area,and selecting the location with high wind speed and high frequency can effectively improve the utilization rate of wind energy of wind turbine.The incoming wind speed is independent of the blade surface load characteristics.When designing and optimizing the wind turbine impeller,the safety and reliability of the connection position between the blade and the support rod in the upwind area should be considered.The reliability study shows that the use of LY12 CZ material to make the vertical axis wind turbine impeller is safe and reliable.