Spray Charateristics of Non-Reacting Diesel Fuel Spray by Experiments and Simulations with KIVA II Code

This paper describes the particle distribution in Diesel sprays by a numerical simulation with KIVA II code based on our experimental results[l]. In the experiments, measured spray characteristics were the Sauter mean diameter, tip penetration and spray shapes in variation of fuel injection pressures. The calculated results by KIVA II code with the TAB method were compared to those experimental results. In the simulations, the size distribution of atomized particles and the ratio of their distorting energy were considered with modifications in those magnitudes. The size distribution was changed in its profile, i.e. the degree of freedom φ of the χ-squared function. The distorting motion of particles was discussed in its energy ratio, i.e. the parameter K of the TAB method. The spatial distribution of particles was examined with/without usage of the collision and coalescence between them. Through the analyses, it was shown that the justification in the parameters, such as φ or K, could successfully estimate the actual droplets distribution in the Diesel spray. For the case of non-usage of the coalescence option, φ = 6 and K = 0.89 are shown to be the proper magnitudes in variation range of injection pressure from 55 MPa to 120 MPa at a constant ambient condition.