Numerical Simulation of 2D Axisymmetric Flow Within Pressure swirl atomizer using InterFoam

Abstract

This study evaluates the open-source CFD solver InterFoam for simulating multiphase flow in a 2D axisymmetric pressure-swirl atomizer using water and air. Motivated by the computational and experimental constraints of 3D studies, the research investigates two atomizer dimensions under a laminar flow assumption. The Volume of Fluid (VOF) method and Continuum Surface Force (CSF) model are employed for interface tracking and surface tension. Qualitatively, the solver accurately captures key flow features, including air-core formation, swirling sheet emanation, and characteristic low-pressure distributions. Quantitatively, interFoam shows excellent agreement with experimental data for Case 1, with average swirling velocity errors of 6.11% at the inlet and 7.18% at the exit. However, Case 2 resulted in significant errors (49.05% and 14.43%) because the laminar assumption is invalid at the high Reynolds number (Re  74,246) present. This highlights the necessity of turbulence modeling for high-Re pressure-swirl flows. Finally, the solver’s performance in predicting the flow number, discharge coefficient, and spray cone angle outperformed literature findings based on inviscid analysis and maximum flow theory. The results suggest that accurate representation of swirling velocity profiles, alongside the swirl number, serves as a critical indicator for when turbulence models must be adopted.