A New Energy-based Model for the Prediction of Primary Atomization of Urea-Water Sprays

The aim of this work is the development of an energy-based model to predict primary break-up of urea and water (Ad Blue) sprays in condition typical of Selective Catalyst Reduction (SCR) systems. The atomization model for Ad Blue injection, developed in the present investigation, performs an energy balance of the liquid column to asses its deformation near the nozzle exit and to predict the dimension of droplets after the primary break-up. To formulate the energy balance it is necessary to evaluate several terms: the theoretical kinetic energy of the jet in absence of dissipation, its real kinetic energy, the fraction of energy dissipated due to turbulence effects, the surface energy before break-up, the surface energy of the droplets after the break-up. The model was implemented in the KIVA3v code and experimental data from Malvern analysis were used for the validation.