Icing Simulation Results Using Lagrangian Particle Tracking in Ansys Fluent Icing

This paper introduces the Lagrangian particle tracking technology readily available in Ansys Fluent in the in-flight icing simulation workflow, which normally uses the Eulerian approach for droplet flows. The Lagrangian solver is incorporated in the Fluent Icing workspace which is to become the next-gen in-flight icing simulation tool provided by Ansys. Lagrangian tracking will eventually be used for SLD and ice crystal rebound and re-impingement calculations in the Ansys workflow. Here we introduce some preliminary results with the current state of its implementation as of Fluent Icing release 2023R2. Example cases include several selections from the 1^st Ice prediction workshop with experimental comparisons as well as results obtained earlier with the Eulerian droplet solution strategy. Collection efficiency comparisons on clean geometries show good agreement between Eulerian and Lagrangian methods when the particle seeds are in the millions range. Shadow zones are resolved with more clarity when Lagrangian tracking is used. SLD and ice crystal rebound simulations significantly benefit from the Lagrangian method, as all wall interaction instances per track can be resolved in a single pass. Turbulent dispersion effects that are built-in to Fluent’s Lagrangian tracking are studied. The impact of turbulent boundary layers on small droplets is investigated. A change in collection efficiency due to particle velocities redistribution when they go across a turbulent structure is observed on a simple test case but the impact of turbulent dispersion on the validation cases collection efficiency is negligible. Multi-shot icing simulations on swept wings produce more detailed ice shapes for the same number of shots when Lagrangian method is swapped in for the Eulerian solver.