| APU has become an indispensable configuration for modern civil aviation aircraft with its low emission and high performance.As the core component of APU,turbine is the key component that determines the performance and service life of APU.The APU turbine nozzle is impacted by the high-temperature and high-pressure gas discharged from the combustion chamber,and the working conditions are extremely harsh.Therefore,the failure of the turbine nozzle often affects the operation of the entire APU,and also determines the life of the APU.Firstly,the FMECA method is used to analyze the failure mode of the turbine nozzle with the working time of about 6000 hours and the influence of the failure mode on the APU and the degree of damage in this paper.It is concluded that the vane crack and material loss of the turbine nozzle would cause great hidden dangers to the operation of the entire APU.Secondly,through the acquisition of the APU turbine nozzle use time data,we collect data to make use of least squares fitting,get the most conforms to the data model of turbine nozzle life distribution,the chi-square test of goodness of fit,to determine the APU nozzle life distribution obeys Weibull distribution,and then get the reliability function of the model.The reliability of the APU turbine nozzle was analyzed by the obtained Weibull distribution function.Finally,ANSYS software is used to conduct thermodynamic analysis of APU turbine nozzle.CATIA was used to build a 3d model of turbine nozzle with cooling measures,and then imported into ANSYS for thermodynamic calculation under relevant boundary conditions.The calculated results show that the maximum thermal stress of the APU nozzle is2.3GPa,which is located on the oxide layer of the thermal barrier coating at the slit of the trailing edge of the blade.The research results of this paper have reference value for the engineering application of APU turbine nozzle. |
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