Modeling Aspects of the Injection of Urea-Spray for NOx Abatement for Heavy Duty Diesel Engines

Book chapter, 2011

Eulerian-Lagrangian simulations of an evaporating water-urea spray have been performed. Velocity, temperature, composition and size distribution are simulated. The chapter contains an extensive discussion of what forces and mass/heat transfer models that should be included. Evaporation of water is included and evaporation and reaction of urea is modeled using a new model for the urea vapor pressure, previously developed by the authors. The main objective of this chapter is to present a guide how to model a water-urea spray including mass and heat transfer. It is shown how the modeling of turbulent dispersion and the choices of injector position affects the model predictions in terms of spray uniformity and residence time.