A Computational Study to Investigate the Effect of Altitude on Deteriorated Engine Performance

摘要

This study presents an investigation on the effect of operational altitudes on the performance of the deteriorated engine.A two-spool high bypass ratio turbofan engine is used as the test subject for this study.The engine is modelled in Gas Turbine Simulation Program(GSP)based on an existing engine model from literature.Real flight data were used for the validation.Deterioration rate of 0.1% per day is applied for all turbofan components engine.The simulation is performed by varying the altitude from sea level until 9000m.Results obtained show reduction in air mass flow rate and engine thrust as altitude increases.The reduction in air mass flow rate is due to the lower air density at higher altitude hence reduces amount of engine thrust.At 1000m to 4000m,thrust specific fuel consumption(TSFC)of the engine is improved compared to sea level.However depleted in TSFC is shown when the aircraft flies at altitude higher than 4000m.At this altitude,the effect of air density is dominant.As a result,the engine is required to burn more fuel to provide a higher thrust to sustain the aircraft speed.More fuel is consumed hence depletion in TSFC is obtained.