Research On The Influence Of Reduced Thrust Takeoff On The Severity Of High Pressure Turbine Blades

Severity is an important correction factor for estimating maintenance intervals and maintenance costs of aero-engines,which can be corrected according to the working severity of the engine in actual use,so as to improve the forecast accuracy of engine sent back to the factory time,maintenance interval and maintenance cost.High-pressure turbine blades are very important for the characterization of engine severity.The severity of key components of aero-engines(high-pressure turbine blades)is closely related to the actual use of the engine.In this paper,finite element numerical simulation analysis and theoretical analysis are used to reduce The severity of the working blades of an aero-engine high-pressure turbine under the condition of thrust take-off was studied.Based on the typical flight missions of civil aviation airliners,the entire range of the aero engine is simplified into different flight segments.Through the established steady-state component-level performance model of this type of engine,input engine thrust and other external conditions to calculate the performance parameters of each segment under different thrust reduction takeoff conditions;then use the scanned point cloud distribution of the high-pressure turbine blades Reverse modeling software and UG modeling software establish a three-dimensional geometric model of the blade with cooling structure.Use ANSYS WORKBENCH finite element simulation platform to perform flow-thermal-solid coupling simulation analysis of high-pressure turbine blades,calculate the temperature,stress and strain distribution laws of turbine blades under different flight segments and reduced thrust takeoff conditions,according to the simulation results determine the assessment location of the turbine blade,and obtain the temperature,stress and strain values of the blade assessment location under different working conditions.The results show that the maximum stress and strain of the turbine blade meet the design requirements.Considering the fatigue damage and creep damage models,as well as the finite element simulation results of turbine blades under different flight stages and different thrust reduction take-off conditions,Based on Manson coffin theory to use average stress modified morrow low cycle fatigue prediction model and Larson Miller creep damage prediction model are used to predict the fatigue damage and creep damage of turbine blades under different thrust reduction cycles.The linear damage accumulation method in the fatigue/creep damage prediction model is used to calculate the total fatigue/creep damage of the turbine blades under different thrust-reducing takeoff cycles.The empirical severity equation is used to calculate the working severity of the high-pressure turbine blades under different thrust-reducing takeoff cycles.