CFD−Phenomenological Diesel Spray Analysis under Evaporative Conditions

Abstract

A combined analysis of computational fluid dynamics (CFD) and phenomenological model is proposed in this work to improve the liquid length predictions of diesel sprays under evaporative conditions. The stable diameter of droplets was evaluated using a trade-off mechanism between a standard CFD model and a phenomenological correlation, and this allowed a better prediction of the measured maximum liquid length than by using the collision models. The standard drop drag coefficient calculation was corrected with empirical correlations that introduce different effects, such as drop deformation, void fraction effects, and the influence of the mass transfer from liquid to vapor phase during the evaporation of droplets. Moreover, the heat and mass transfer between the droplets and gas were also corrected considering a larger surface area of the droplets caused by their deformation during the break-up process. Experimental data available in literature has been used to validate the model for single components and diesel fuels, and encouraging results have been obtained contributing to a better simulation of the atomization, breakup, and evaporative processes in sprays.