  In liquid-fueled combustion systems, optimization of the fuel atomization
process is critical to reducing fuel consumption and lowering pollutant
emissions. Accurate and efficient computational modeling of liquid atomization
can open the door to spray optimization, however it presents a significant
challenge to modelers due to the extremely complex flow field and wide range of
length and time scales involved. In this work, a multi-scale and multi-domain
simulation strategy is used to model end-to-end the turbulent spray produced by
a swirled two-fluid coaxial atomizer, a device that utilize a high-speed
swirled gas stream to destabilize a co-flowing low-speed liquid, widely used in
systems such as fuel injectors. Our computational method relies on sub-grid
scale modeling; in particular, we will introduce a thin structure break-up
model to account for topology changes, converting thin liquid structures into
spherical Lagrangian particles. With such simulations, the impact of swirl on
the break-up process can be analyzed by varying the swirl ratio, and we aim to
quantitatively validate our simulations against experiments at identical
operating conditions, including drop size statistics.
