透平机叶轮断裂分析

Fracture Analysis of Turbine Impeller

透平机叶轮在装置大检修后刚开机就突然发生断裂。宏观检察发现轮盘断口上存在铸造缺陷,经评定排除了铸造缺陷造成断裂的可能。从断裂裂纹的位置、走向,端口形貌,自锁控制系统动作过程的分析得知,由于管壁上有残留水会使介质中水分增加,从而引起叶轮超速,在制动控制系统有误的情况下使叶轮不能按照正确程序停车,造成叶轮超速进一步加剧,产生过高的离心力,从而引起叶轮断裂,是这次事故的真正原因。

The turbine impeller was fractured suddenly when it started to work,after it was examined carefully.After Macro examination,casting defects were found on roulette;the casting defects were assessed.The results showed the defects may have caused the rupture.From the analysis of fracture crack location,direction,port shape,self-locking control system which moved the process,it was learned that the remaining water left on the pipeline increased the moisture in the medium and csused the impeller to speed excessively.Because of an error program in the control break system,the impeller could not stop in the correct procedures,and the speed of impeller was further accelerated.The centrifugal force was generated too high,so the high centrifugal force was the real cause of the fracture accident.