Study Of The Influence Of Nozzle Shape On The Primary Atomization Process By Means Of Direct Numerical Simulation

Abstract

The atomization process is a physical phenomenon that takes place as an essential mechanism in many industrial fields. Even though it has been widely addressed in the literature, there are still several aspects of primary atomization that are far from being understood. In order to shed light on the physical processes that take place in the near-field of the injection, Direct Numerical Simulations (DNS) are rising as a fundamental tool to provide detailed data where the optical access is difficult and expensive. Nevertheless, most real engineering conditions are too complex to be accurately resolved with DNS. Hence, a more fundamental standpoint is chosen to first understand the fundamental mechanisms that drive the process. In this context, this work presents a study of the influence of the nozzle shape on droplet formation by using DNS simulations performed with the Paris-Simulator code. The injection inflow conditions are obtained by mapping results from Large Eddy Simulation (LES) of an elliptic duct with eccentricity factor of 0.85, maintaining the bulk velocity and the crosssection area. The Reynolds number for all cases is maintained around 5000 and the Weber number around 26000. Results are compared to a round jet DNS simulation also performed with a mapped boundary condition. The main aim of the work is to understand how the elliptic cross-section eccentricity affects the atomization regime, breakup mechanism, droplet azimuthal distribution and turbulent structures.