Numerical Simulation of Transient Operations in Aeroengines

In this paper a numerical method for predicting the unsteady performances of an air-breathing engine is presented. The flow around the nacelle and inside the engine ducts (e.g. air intakes, nozzles) is solved by CFD computations, while the flow evolution through compressor and turbine bladings are simulated via low order CFD models and actuator disks. Shaft work balance allows to derive the instantaneous rotor speed and to couple the fluid and engine dynamics. Without loss of generality, the methodology is explained assuming the turbojet as the reference engine.