A Multi-Physics Simulation of Heat Transfer in Iced Airfoils under Realistic Icing Conditions

This work presents a high-fidelity, multi-physics framework for investigating the heat transfer of aircraft icing under realistic conditions. The methodology integrates a compressible Wall-Modeled Large-Eddy Simulation (WMLES) solver for aerodynamics, a Lagrangian particle tracking method for droplet impingement, and an unsteady Conjugate Heat Transfer (CHT) solver for the solid ice domain. This framework is applied to a NACA 23012 airfoil featuring laser-scanned rime ice roughness to analyze the interplay between surface topology, droplet impingement, and thermal conduction driven by the solidification of supercooled droplets. Results reveal that surface roughness induces high-frequency spatial variations in the local collection efficiency, leading to a heterogeneous heat source distribution from droplet solidification. However, lateral conduction within the ice layer diffuses this localized heat generation, resulting in a surface temperature field that is notably smoother than the impingement profile. Analysis of the interfacial energy budget at the stagnation region indicates that approximately 30\% of the latent heat released by droplet freezing is conducted into the ice layer. Temperature profiles within the solid reveal that near the inner airfoil skin, the conduction is mostly one-dimensional. However, near the highly irregular ice surface, the three-dimensional nature of the roughness elements drives multi-dimensional conduction, redirecting heat laterally from warm windward faces to cool leeward regions of individual roughness elements. These findings suggest that traditional icing models relying on isothermal wall assumptions or simplified one-dimensional conduction may not adequately capture the local thermodynamics of rough ice accretions.