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A through-flow based Monte Carlo particle trajectory simulation is used to calculate the ice crystal paths in the low pressure compressor of a high bypass ratio turbofan engine. The simulation includes a statistical ice particle breakup model due to impact on the engine surfaces. Stage-by-stage ice water content, particle size and particle velocity distributions are generated at multiple flight conditions and engine power conditions. The majority of the ice particle breakup occurs in the fan and first LPC stage. The local ice water content (IWC) within LPC is much higher than the ambient conditions due to scoop effects, centrifuging and flow-path curvature. Also the ice particles approach the stators at lower incidence angles than the air flow. The simulation results prompt the need to revisit the approach for properly setting up boundary conditions for component or cascade testing.

This paper presents liquid water and ice crystal collection effects for a generic axisymmetric turbofan engine inlet over a range of flight Mach numbers, inlet mass flow ratios, droplet inertia parameters and droplet free stream Reynolds numbers. The ingested water mass flow is properly defined in the context of an Eulerean droplet trajectory calculation method to obtain the collection efficiency. Collection efficiency is then correlated against the mass flow ratio of the airflow rather than the velocity ratio as has been common practice. These results are also compared against published test results. The local concentration effect of liquid water content (LWC) is also described, which can be important in aircraft probe design and placement.