涡轮轴断裂条件下的涡扇发动机性能建模

为了研究双轴混合排气涡扇发动机高压轴断裂失效后的动态性能，建立了轴断裂条件下涡扇发动机过渡态的共同工作方程，以及各部件考虑容积效应和气体惯性力的模型部件。在此基础上，分析了地面起飞状态和巡航状态下涡扇发动机高压轴断裂后发动机气路参数的瞬态响应规律和机理。研究表明:涡扇发动机高压轴断裂会在不超过05s的时间内导致压气机喘振、涡轮前温度超温、涡轮转速超转等继发性危害事件。在不同飞行状态下出现的轴断裂，上述事件发生的先后次序各不相同。尤其在地面起飞状态下，涡轮超转事件极可能先于压气机喘振现象而发生，012s内涡轮即可达到其破裂转速。这些都需要在航空发动机被动安全设计中给予足够的重视。 

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.