Liquid film dynamic on the spray impingement modelling

The present paper addresses a liquid film sub-model included into a computational model that aims at reproducing the spray impingement phenomena. This numerical extension incorporates the spread of the liquid film over the neighbouring nodes due to the dynamic motion induced by the film inertia but also the exchange of mass between the liquid layer and the incident and splashing particles. Moreover, the dimensionless film thickness parameter is introduced into the sub-model by mean of an experimentally-deduced correlation that can be fitted and updated to specified conditions. In order to realize how the model behaves with different influencing parameters, a thorough investigation is performed: the results that are obtained with and without the liquid film sub-model are compared against the experimental data for two crossflow rates. The integration of the computational extension with the spread/splash transition criterion is also evaluated by considering two types of transition criteria: one that takes into account the effect of the film thickness and one that does not. The results show that the latter option in combination with the sub-model do not distinctly enhance the simulation results, contrary to what happens using the transition criterion that considers the film thickness as an influencing parameter. In this case, the model with the computational extension reveals better prediction results than the one without it, which indicates the necessity of considering the liquid film formation for spray impingement simulations but also a splash threshold that takes into account the influence of the film thickness.
Fundação para a Ciência e a Tecnologia