APPROACH TO MODELING CONTINUOUS TURBINE-ENGINE OPERATION FROM STARTUP TO SHUTDOWN

A generalized turbine engine start simulation (mathematical model) has been developed and demonstrated. The model, designated as ATEST-V3, is capable of simulating engine operation continuously from near static (zero speed) conditions to maximum engine power including windmill starting, spooldown starting, and starter-assisted starting. The enhanced capability to simulate the engine starting process provides the means to characterize and understand engine system operational behavior during critical startup and shutdown operations. ATEST-V3 is based on an aerothermodynamic matching of the major components. The component-matching technique is widely used for steady-state and transient turbine engine simulations that typically exclude subidle and starting operations. The same approach is shown to be applicable to engine starting operations by modeling component behavior continuously from zero to maximum power. The combination of an existing transient engine simulation and a numerically stable component-matching algorithm provided a foundation for extending the simulation capability to subidle engine operation and engine starting. ATEST-V3 was applied to a modern flight-type turbofan engine which demonstrated the capability to simulate windmill, spooldown, and starter-assisted starts at various flight conditions. Finally, a comparison is made between model results and engine test data.