Computational modelling of spray impingement accounting for the wall film formation

This thesis is concrned with the development of models related to spray/wall interaction phenomena. To this end, a literature survey is first performed on droplet and spray impingement and liquid film flow processes. In this preparatory step all physical parameters relevant for the description of these phenomena are isolated and their relevance is described. Three main different droplet impingement regimes are identified and the existing regime transition criterion is theoretically justified by applying a scaling analysis. A semi-empirical spray impingement model is formulated on the basis of the experimental observations, and the mass, momentum and energy conservation constraints. Correlations are introduced which correspond to the experimental findings valid for polydispersed sprays and an attempt is made to identify their physical meaning. A hypotheses for the secondary droplet velocity and the mass distribution are introduced. The basis for these hypotheses is found in the theory related to the propagation of the kinematic discontinuity and the ejection of the liquid sheet. The model includes a random procedure to determine some of the post-impingement characteristics from pre-described probabilities.