Numerical Simulation of In-Flight Icing Supercooled Large Droplets Freezing via Smoothed Particle Hydrodynamics

This chapter presents a multiphase Smoothed Particle Hydrodynamics (SPH) framework in the form of “numerical experiments” of supercooled large droplets (SLD) impingement and solidification under flight conditions. SPH, a mesh-free CFD method that can handle complex interfaces, solves the inviscid momentum and energy equations for flow and heat transfer, with an equation of state linking pressure and density. Numerical techniques such as a latent heat model to account for phase change, a supercooled solidification model to capture dendritic freezing, and a contact angle model to represent the non-wetting properties of hydrophobic surfaces, are presented. A multiphase model handles interfacial flows and a fixed ghost particle method enforces the boundary conditions. The framework is validated against a limited number of available open literature experimental results and then extended to SLD droplets impinging at flight speeds on water films, cold solid surfaces, superhydrophobic coatings, and iced surfaces. The result is a comprehensive toolset for the parametric study of SLD impingement to pave the way for an SLD icing simulation model more specifically applicable to aircraft flight speeds.