| With the development of economy,the phenomenon of energy shortage is becoming more prominent than before.As the highly efficient renewable energy,wind energy has attracted much intention all over the world.There are many problems appearing especially in the hidden dangers of wind turbine blade defects to safe production,while the global installed capacity of wind power increases year by year.If the wind turbines operate for a long time,some defects appear on the blades,such as white spot,sand hole,gel coat off,glue and fiber layer damage and others.These defects influence the service life,controllability and safety directly.Because some defects have no obvious characteristics from the microscopic angel,it is hard to detect the defects.Infrared thermography technology has the advantages of intuitionism and rapidness,which is the suitable way for the detection of wind turbines.In this thesis,the infrared thermography temperature of wind turbine blade defects is studied by numerical analysis.The main work is as follows:Firstly,this thesis described the principle and characteristics of infrared thermographic detection technology for wind turbine blade defects.The thesis introduced the fundamental theory of heat transfer,heat convection and heat radiation.In the same time,it compared and analyzed the active and passive infrared thermography detection methods.In the end,the active infrared thermographic detection technology was used as the defect detection method of wind turbine blades,which provided theoretical basis for the subsequent numerical analysis of the infrared thermography of wind turbine blade defects.Secondly,the thesis established the 3D modeling of wind turbine blade defects.The material of wind turbine blade was selected while the coating defects and their positions were determined.Then,multilayer wind turbine blade defect mathematical microelement model were selected,and the coating simulation method of super layer and the geometric parameters of microelement model of specific size were used.The thesis built the 3D model of different wind turbine blade defects with thickness,width and length by Solidworks to lay the foundation for the further subsequent numerical analysis.Finally,the thesis imported the wind turbine blade material library and defect model into Ansys.The meshing of the model was carried out,and the temperature field was solved and post-processed.After these steps,it simulated the infrared thermographic detection process of wind turbine blade defects and numerically analyzed the defect characteristics of wind turbine blades and the factors such as ambient temperature and heating intensity.The result shows that some factors are positively proportional to the thermographic temperature,such as the specific defect width,defect length,heating intensity and defect thickness within a certain range.However,ambient temperature is inversely proportional to thermographic temperature.The closer the detection surface is,the more obvious the thermographic temperature of the coating defect is.It shows that wind turbine blade defect parameters and external factors have a certain influence on the thermographic temperature.The wind turbine blade defects can be detected by using this numerical analysis method. |
