Effect of Particle Diameter on Primary Breakup of High-Pressure Diesel Spray Atomization: A Study Based on Numerical Simulations Using the Eulerian-Lagrangian Model

The coupling of Eulerian and Lagrangian methods in the Eulerian-Lagrangian Spray Atomization (ELSA) approach is critical. This study proposes an equation for the primary breakup particle diameter D of a diesel fuel spray and adopts it as a key transition criterion for coupling. A three-dimensional diesel spray is modeled by the large-eddy simulation (LES) approach. This improved ELSA simulation was conducted using various transition criteria for particle diameter D-cr. The results show that fuel spray experiences two stages: stage I, when a liquid column appears without a dispersed phase, and stage II, when primary breakup occurs with many discrete particles. Although D-cr has little influence on the macro-spray characteristics, such as top penetration distance S and spray cone angle theta, it has significant effects on discrete particles, such as their number, average diameter, distribution and location, and spray cone area. D-cr should be determined on the basis of actual operating conditions.