Numerical Simulations of Ice Particle Transport at Representative Turbofan Compressor Conditions

Abstract Engine icing threatens compressor operation and service life. Ice crystal ingestion at cruise and descent flight phases results in smaller, partially melted crystals entering the engine core. Here, crystals stick to stationary surfaces driven by the presence of a water film. Modeling of ice crystal conditions is needed to understand threat areas within the core operating envelope. A particle transport model in three dimensions combining tracking, heat transfer, and phase change along with a turbophoresis model is presented for nonspherical mixed-phase ice crystals. Furthermore, crystals can fragment, melt, and agglomerate along the gas path. This affects heat transfer, phase change, and ice porosity which will implicate the deposition location and composition. The model is validated against previous altitude icing wind tunnel experiments at compressor operating conditions. Particle advection is modeled using an Euler–Lagrangian approach with two-way mass-energy coupling. Particle turbophoresis is modeled using a discrete random walk approach. The model is seen to predict particle cloud mass distribution to within 15% of the experimentally measured total water content. Particle melting is investigated relative to particle size and aspect ratio. High aspect ratio particles result in 5–20% phase change augmentation depending on the particle angle of attack. Two-way coupling is shown to increase the melt ratio by up to 10% and reduce the total water content by up to 25% compared to one-way coupling. The model provides a framework for compressor stage ice particle transport and deposition in ice crystal icing conditions.