Transition performance simulation of turbine shaft fracture in high bypass ratio turbofan engine with split flow

To deal with the dynamic performance of biaxial high bypass ratio turbofan engine with split flow in shaft fracture event and find out the first hazardous event after shaft fracture，the common working equation and performance model of high bypass ratio turbofan engine with split flow capable of simulating the dynamic response of airflow parameters in millisecond time scale were established based on the simulation platform independently developed.The dynamic response of airflow parameters was simulated in the order of milliseconds in the model.The transient response law and mechanism of gas path parameters of a civil turbofan engine with high bypass ratio under high and low-pressure shaft fracture in the take-off state and the cruise state were calculated and analyzed by using the model，which provided a basis for the design of passive safety.The results showed that the first hazardous events that occur within a few tens of milliseconds after the shaft fracture of the high and low-pressure shafts were the surge of the medium-pressure compressor and the over-rotation of the turbine rotor；at the same time，the temperature rose in front of the turbine.