MODEL VALIDATION THROUGH NEAR-FIELD SPRAY DYNAMICS: A CASE STUDY ON ASYMMETRICAL OFF-AXIS NOZZLE

Artikel i vetenskaplig tidskrift, 2025

In diesel engines, fuel spray characteristics can partially control efficiency and emissions. Modeling the spray characteristics can enhance our understanding of the intricate relationship between combustion dynamics and fuel spray characteristics. This study validates a Eulerian CFD model of a spray based on the near-field dynamics of the liquid core at the beginning of the injection. We performed the simulation using AVL Fire based on a prototype single-hole off-axis orifice, which is particularly designed to promote the cavitation intensity and make it more appealing for model validation and fundamental studies. In addition, the simulations spanned various initial conditions, including two injection pressures and three levels of initial liquid fuel in the sac, namely empty, semi-full, and full. Our findings demonstrated remarkable alignment between the model and experimental data when starting with an empty sac. Furthermore, our model presents in-nozzle flow characteristics, which reveal the radial velocity distribution within the nozzle and orifice. In addition, the investigations unveiled a counter-rotating flow inside the orifice, which describes the swirl formation within the spray.