Single-drop empirical models for spray impact on solid walls: A review

Simplified impingement models are largely used in numerical simulation of spray impingement on solid walls, since the direct simulation of multiple drop impact is outside of the present computer capabilities. These models are usually semiempirical, based on single-drop impact experimental data and some reasonable constraints to allow extrapolation to different impact conditions. This article presents a comparison of the most commonly used drop impingement models in the present scientific literature and in commercial codes. A classification of the models and a unified scheme is proposed in terms of driving variables and outcomes. Every model is then analyzed and its peculiarities and possible weaknesses are pointed out, especially those related to the physical consistency. Finally, a comparison among the various models for a possible use in Gasoline Direct Injection (GDI) and diesel spray simulation is presented.