航空发动机叶片残余型芯中子照相检测

Neutron Radiography Detection of Residual Core in Turbine Blades

空心涡轮叶片是航空发动机最重要的热端部件之一,叶片内腔若存在残余型芯将严重影响冷却效果,导致叶片过热而提前失效,对发动机造成致命损伤。常用无损检测方法由于检测范围无法覆盖完整叶片或检测灵敏度不足等原因,无法有效检出叶片内腔残芯。中子照相检测与X射线照相检测原理类似,但衰减特性迥异,使其检测叶片残余型芯成为可能。国外叶片制造企业自1970年代就开始采用中子照相技术检测叶片残芯,并建立企业标准;我国相关研究工作不足10 a,虽然目前已在某些发动机叶片上开展试验性应用,但缺少检测标准和中子源资源不足等问题亟待解决。

Hollow turbine blade is one of the most important hot end components of aero-engine.The residual core produced in the blade manufacturing process will seriously affect the cooling effect,which will lead to blade overheating and premature failure,causing fatal damage to the engine.The common non-destructive testing methods cannot detect the residual core in hollow blades effectively because the detectable area cannot cover the whole blade or the detection sensitivity is insufficient.The principle of neutron radiography is similar to that of X-ray radiography,but the attenuation characteristics are quite different,which makes it possible to detect the residual cores.Neutron radiography has been used to detect the residual core in turbine blades since 1970s abroad and related company standards have been established.The research work in China is less than 10 years,although experimental application has been carried out on some blades,the problems of lack of inspection standards and neutron source resources need to be solved.