A Forward Model for Route- and Season-Dependent High-Pressure Compressor Efficiency Deterioration in Turbofan Engines

Abstract

Civil turbofan engines lose compressor efficiency every time they fly through particle-laden air. Fouling of the high-pressure compressor (HPC) is the dominant recoverable performance-loss mechanism. Existing studies treat environmental particle exposure, blade-row deposition and stage-performance deterioration as separate problems, which limits understanding of the issue. Stage-stacking approaches require deterioration levels to be prescribed rather than derived from the operating environment, leaving the causal chain from route conditions to engine performance unresolved. This paper presents a forward simulation framework that closes this gap by propagating route-, season-, and altitude-dependent particle exposure through four successive layers: (1) flight-phase-resolved HPC inlet dose calculation; (2) stage-wise deposition across the HPC; (3) deposition-to-deterioration mapping; and (4) stage thermodynamic stacking, yielding overall fouled HPC isentropic efficiency. Demonstrated on a representative civil high-bypass turbofan baseline with characteristics similar to the CFM56-7B, the predicted deterioration milestones are confirmed in magnitude and timescale against publicly available in-service support datasets. The results reproduce front-stage-dominated deposition, rapid early deterioration with asymptotic saturation, and clear route- and season-dependent fouling behaviour. To our knowledge, this is the first model that closes the complete chain from operationally resolved environmental exposure to the overall loss of HPC isentropic efficiency in a single physically traceable forward framework.