Component Degradation Modeling in An Advanced Three-Shaft Turbofan Engine

Performance deterioration of gas turbine engines in service is inevitable. Several severe damages could be generated, such as fouling, erosion, corrosion, rubbing wear, hot end component damage. All these cumulative effects would cause deterioration and the engine might not satisfy the design requirements. This paper aims to investigate the influences of component degradation regarding efficiency and flow capacity on the engine performance, transient behaviour and aircraft level performance. 1%, 3% and 5% degradation of each component is studied separately to obtain the resultant engine deterioration. Considering the engine deterioration is always caused by the combination of efficiency and flow capacity, several cases with superimposed factors are simulated in the flight mission analysis. The outcomes indicate that LPT and HPC efficiency degradation exerts an obvious effect on engine performance. A 5% decrease in LPT and HPC efficiency would result in a 4.74% increase in SFC and a 4.27% rise in T4 separately at the takeoff point. More importantly, the operating lines of Fan and IPC are pushed towards the surge line during a slam operation to take-off condition. The combination of efficiency and mass flow degradation of 5% for each component demonstrates a noticeable 5.8% rise in block fuel. Furthermore, the corresponding NOx and CO₂ are unavoidably increased by 15.3%, 5.8% and 5.8% respectively. It could be concluded that component degradation should be closely observed to prevent catastrophic consequences.