High fidelity and simplified modeling of evaporation over hydrophobic surfaces for anti-icing applications

Purpose – In-flight icing simulation tools relying on the Messinger model assume a continuous liquid layer wetting the airfoil surface and do not consider the effect of surface morphology. This study aims to introduce the impact of hydrophobic and superhydrophobic surfaces via the modelization of a discontinuous wetting layer evolving as a population of droplets. Design/methodology/approach – An individual based modelization for the evolution of an impinging droplet population on a heated substrate is applied to configurations representative of in-flight icing applications. A new phenomenological model is developed for the droplet evaporation during thermal anti-icing operations, validated with experimental evidence and integrated with the in-house Lagrangian code. Findings – The individual-based model provides a reliable prediction of the droplet distribution resulting from the combined effect of incoming impinging mass flow and evaporation mass flow. The sample cases demonstrate that the topology of the water layer, and in particular the droplet size distribution typical of hydrophobic surfaces, actually affects the heat transfer process and anti-icing system performances (such analysis was limited to dropwise condensation only). Originality/value – Such information are the basis for introducing the impact of surface characteristics in a probability-based model for icing simulations, filling the gap of previous Messinger-like models. Thus, the proposed individual based modelization offers a viable platform to develop and validate efficient tools for the accurate, yet efficient, simulation of anti-icing thermal systems coupled with hydrophobic and superhydrophobic surfaces.