Experimental and Numerical Analysis of Diesel Common Rail Fuel Sprays in a Air Quiescent Vessel.

A Phenomenological Spray Model (PSM) has been proposed and implemented for the analysis of nonevaporating Diesel fuel sprays, in order to reduce the typical grid sensitivity of commercial CFD codes. The proposed model allows the tip penetration, the spray angle and the initial Sauter Mean Diameter and diameter distribution of the fuel droplets to be predicted through phenomenological relationships. An extremely reduced set of experimental data is required to set-up the initial droplet characteristics. The proposed model was validated by comparing the simulation results with experimental data obtained using laser sheet techniques for spray tip penetration, spray cone angle and spray shape, and with experimental data obtained through PDA techniques for the droplet velocities and sizes. Different pressure levels were considered for the rail injection pressure (50, 100 and 135 MPa) and for the vessel backpressure (1, 3 and 5 MPa).