某燃气轮机低压涡轮叶片断裂故障分析

Failure Analysis of Low Pressure Turbine Blade Fracture of a Gas Turbine

低压涡轮叶片作为燃气轮机内流道的热端部件,长时间受到气流冲击,受离心载荷、气动载荷和热载荷的综合影响,对叶片强度要求较高。某燃气轮机由退役航空发动机改制而成,通过电站长试考核考验燃气轮机寿命,在考核期间发生低压涡轮叶片断裂故障。针对故障进行分析、试验及计算,确定叶片断裂的主要原因是叶片共振引发高周疲劳,采取措施是燃气轮机长期工作时迅速通过易发生多阶次共振的危险转速范围。

As the hot part of the inner flow passage of gas turbine,the low-pressure turbine blade is impacted by airflow for a long time,and is affected by centrifugal load,aerodynamic load and thermal load,which requires higher blade strength.A gas turbine was reformed from a retired aero-engine,and the remaining life of the gas turbine was tested by the long-term test of the power station.The low-pressure turbine blade fracture occurred during the examination period.Through the analysis,tests and calculation of the fracture phenomenon of the low-pressure turbine blade of a gas turbine in depth,the main reason for the blade fracture was high cycle fatigue caused by blade resonance.Here the measures taken are that the gas turbine should pass through the dangerous speed range of multi-order resonance rapidly in long-term operation.