Transient Performance Calculation Model for Turbofan Engines Coupled with Air System

This paper establishes a computational model for a two-spool mixed turbofan engine. By using the direct simulation method, its transient performance is solved. A one-dimensional model of the air system network is established and solved, which result has been used to build a characteristic map, coupling to the engine’s model. The effects of the coupling on the bleed and performance parameters are calculated in two conditions: the former one accelerates from idle state to maximum-continuous state, the latter one decelerates from maximum-continuous state to idle state. The result shows that, introducing the air system into engine’s transient performance model can reduce cooling flow by approximately 1% at the end of acceleration and approximately 5% at the end of deceleration. Coupling the characteristic map to the engine’s model may lead to extra 3% acceleration time and 1% loss on the surge margin of engine’s compressor. For the deceleration case, the coupling can lead to extra 2% deceleration time and 5% loss on the compressor’s surge margin