A Finite Conductivity Model for Diesel Spray Evaporation Computations

The authors present some spray calculations in a combustion bomb and in a d.i. diesel engine for different test cases varying the formulation of the evaporation model in a modified version of the 3D-fluidynamic KIVA II code. Some numerical tests cases have been performed in a combustion bomb to analyze the influence of the modified evaporation model on droplet heating, evaporation rate and droplet lifetime. The numerical results have been compared with those obtained from the original Spalding model and with some experimental data obtained by an optical technique. In a second set of calculations, the new model has been tested in the combustion chamber of a real d.i. diesel engine. Results in terms of pressure, vapour mass, spray distribution and burned fuel are reported. A preliminary analysis on exhaust emissions has been done.