风机叶片内部缺陷日光激励动态热成像方法研究

Study on the method of daylight-excited thermal imaging of internal defects in wind turbine blades

针对在役风力发电机组叶片内部缺陷类型难以区分的问题,本文提出了基于自然日光激励的动态热成像检测理论与方法,并进行有限元仿真模拟与试件实验研析了自然日光激励下风机叶片不同内部缺陷的动态热成像规律。首先,建立风机叶片切片的有限元传热仿真模型,通过数值计算揭示脱粘、积水两类典型内部缺陷在日光激励热传导物理场下热特征的变化规律;其次,对叶片切片进行同质加工,并利用无人机搭载热成像载荷搭建了日光激励热成像检测平台;最后,在自然日光激励条件下进行全天不同时段下的日光激励热成像实验。仿真和实验结果表明,风机叶片内部脱粘、积水两类典型缺陷在日光激励下将导致表面温度场呈现不同的变化趋势,脱粘缺陷会导致风机叶片表面对应区域出现高温异常到低温异常的动态演化,积水则相反,上述规律将为在役风机叶片的智能运维提供新的方法论。

In response to the challenging issue of distinguishing the types of internal defects of wind turbine blades in service,this paper proposes the theory and method of dynamic thermal imaging detection based on natural daylight excitation.Finite element simulation and experimental analyses are conducted to investigate the dynamic thermal imaging patterns of different internal defects of wind turbine blades under natural daylight excitation.Firstly,a finite element heat transfer simulation model of wind turbine blade slices is established,and the variation rule of thermal characteristics of two types of typical internal defects,namely,debonding and water,is revealed by numerical calculation under the daylight-excited heat conduction physical field.Secondly,blade slice is homogeneously processed,and a thermal imaging detection platform is constructed using unmanned aerial vehicles for daylight-induced thermal imaging.Finally,daylight-induced thermal imaging experiments are conducted during different times of day under natural daylight conditions.The simulation and experimental results indicate that the two types of typical defects of debonding and water inside the wind turbine blade will lead to different trends in the surface temperature field under daylight excitation,and debonding defects will lead to the dynamic evolution of high-temperature anomalies to low-temperature anomalies in the corresponding areas on the surface of the wind turbine blade,while water is the opposite,which will provide a new methodology for the intelligent operation and maintenance of in-service wind turbine blades.