Performance modeling of turbofan engine in event of shaft failure

To deal with the dynamic performance of a two-spool turbofan engine with mixed exhaust in the event of high-pressure shaft failure, the transient matching constraints of the failure turbofan engine were established and corresponding components models were built by taking volume packing effects and fluid inertia effects into consideration. On this basis, a parametric analysis was then carried out to study the regularity and mechanism of the transient response of the gas path in engine induced by shaft failure during takeoff and cruising stage. Results showed that the high pressure shaft failure of the turbofan engine could lead to several hazardous events, such as compressor surge, turbine over-temperature and over-speed, within no more than 0.5s. The time sequence of the above events changed as the shaft failure took place on different flight profile stages. Turbine over-speed was more likely to occur before compressor surge during takeoff stage and the turbine could reach its rupture speed within 0.12s. Special attention should be paid to all of these in the engine passive safety design.