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The study of Supercooled Large Droplets (SLD) has received greater attention in the Aviation industry since the ATR-72 accident in 1994, which was attributed to SLD. This type of icing cloud usually consists of droplets of up to a millimeter in diameter and mean volumetric diameter (MVD) greater than 40 microns1. The analyses of the ice accretion process with SLD have focused mainly on the wing and stabilizers, particularly on the leading edges where accretion can occur beyond the ice protected areas. There are several numerical and empirical models to predict the mass and shapes of ice accreted from SLD, but there are few published papers that focus on SLD accretion within aircraft turbofan engines2, 3, 4, 5, 6, 7, 8, 9. SLD droplets have higher inertia than conventional icing droplets, which leads to their trajectories being less influenced by the aerodynamic forces. However, large droplets are more likely to breakup than smaller droplets when subjected to highly shear flows.

This paper describes a physics-based icing tool for aircraft engines, which have small components compared to the wing geometry of an aircraft. The tool consists of an icing code, viscous CFD software and mesh generator to build ice shapes incrementally to form the final shape. This multi-layered process was developed to predict ice shapes in components with high-pressure gradient flows as found inside engine flow passages. Good agreement was found between experimental and predicted ice shapes for engine inlet guide vanes and different wing geometries.