VAPORIZATION OF A BINARY UNSTEADY SPRAY AT HIGH-TEMPERATURE AND HIGH-PRESSURE

A numerical model has been formulated for a binary droplet spray evaporting under diesel engine conditions. The liquid phase model considers the transport processes of heat conduction and species diffusion and includes variable property effects. The gaseous phase is described by the conservation equations for momentum, energy and species for unsteady, turbulent flows. The solution procedure is based on an Eulerian gas and a Lagrangian drop formulation. It is shown that for spray conditions, characterized by droplets with mean sizes of 20 mum and inlet velocities in the range of 200 m s-1, and by a gaseous atmosphere at a temperature of 500-degrees-C and a pressure of 45 bar, the influence of the diffusive transport processes within the droplet cannot be neglected. The numerical model was used to predict the vaporization rate of n-heptane/n-decane sprays.