Aerodynamic Performance Prognosis of Operationally-Used Aero Engine Compressor Blading

Abstract The operational efficiency of aircraft engines is adversely affected over time due to degradation, manifesting as increased exhaust gas temperature (EGT) and thrust-specific fuel consumption (TSFC). Exceeding critical EGT limits necessitates an overhaul of the engine. During the maintenance of fan and compressor blades, adherence to specific limits outlined in the engine manual is crucial to ensure safe blade functionality. However, current practices lack established criteria for evaluating aerodynamic performance, particularly concerning which geometric parameters — such as leading and trailing edge thickness, chord length, tip clearance, as well as variations in lean and sweep — most significantly impact the performance. Consequently, the extent of engine performance degradation remains uncertain. This study aims to investigate the aerodynamic implications of geometric alterations in compressor blades following usage in a commonly deployed turbofan engine. Serviced blades, processed during maintenance, were digitized and parameterized. A design of experiments approach was employed to create a comprehensive array of synthetic compressor blades based on these parameter variations. Through computational fluid dynamics (CFD) analysis and integration into a fan and low-pressure compressor (LPC) simulation model, as well as a high-pressure compressor (HPC) model, metamodels of the compressor modules were developed. These surrogate models facilitate the assessment of how specific geometric changes impact the aerodynamic efficiency of the compressor, thereby enhancing our understanding of performance deterioration in operational aircraft engines.