Research On The Start Failure Of Civil High-bypass Turbofan Engine On The High Plateau

With the rapid development of air transport in China,the civil transport aircraft staying overnight in the high plateau airport become normal in the airline operation.Although most single channel aircraft running on the plateau chose the CFM56-5B engine as its power plant,but the CFM56-5B engine still has many problems in the start failure during the plateau cold start process because of its flights delay and high cost which affect the airline operation and the flight safety.This paper is focuses on the problems of the CFM56-5B engine which failed in starting in high plateau airport and then to study its common failure mode,failure reason and fuel supply rule.The concrete contents are as follows:(1)On the basis of the high plateau start failure airlines record,and the start failure engine QAR data,comparing with the working parameters from the point of plains and high plateau,cold and hot engine,winter and summer,start-up difficulties and start-up normal,the problems of the common fault mode and characteristics of the high plateau engine Start are studied.(2)On the basis of the common starting hang and starting stall failure mode in the fault tree analysis method,the fault tree are established.Through the minimum cut set analysis of the cold start starting hang fault mode,we get the main possible cause of starting failure.(3)Through the real-time exhaust gas test experiment of the combustion products during the cold start of the high plateau airport engine and the real-time QAR data and the exhaust gas composition test results,the composition and mechanism of the white smoke during the cold start of the engine have been clarified for the first time.Then the problem of the fuel atomization and fuel vaporization in high plateau cold start is verified.(4)The engine start envelope is established through the CFM56-5B engine start failure data and it is verified with the QAR data.The regular fuel supply rule witch to ensure that the engine was started in the cold and hot start of the plateau was established by the statistical software SPSS.And this regular fuel supply rule is also verified its rationality by the QARdata.All this information provided the theoretical basis for solving the problems of the start failure on the high plateau.