Effect of Ice and Blade Interaction Models on Compressor Stability

Abstract

As air traffic continues to increase in the subtropical areas where high moisture laden air is present at subfreezing conditions, engine icing probability increases. It has been shown that compressor stages rematch under icing conditions—front stages are choked, while rear stages throttle due to ice melting and evaporation. Such an analysis uses various empirical models to represent ice-breakup and water-splash processes as ice/water particles interact with rotors/stators. This paper presents a compressor stall sensitivity analysis around different splash models. The effect of droplet splash at both rotor and stator blades, blade solidity effect, and trailing edge shed effect is modeled. A representative ten-stage high-speed compressor section operating near design point (100% Nc) is used for the study. Results show that the temperature drop at high-pressure compressor (HPC) exit and the overall compressor operability are functions of evaporating stages, and droplet–blade interaction models influence them. A comprehensive compressor stability envelope has been evaluated for different models. It is observed that the droplet–blade interaction behavior influences overall compressor stability and the stall-margin predictions can vary by as much as 25% with different models. Therefore, there is a need for better calibration and continual improvement of empirical models to capture compressor interstage dynamics and stage rematching accurately under ice/water ingestion.