A Comparative Study of Turbulence Models for Two-Phase Coaxial Swirling Jet Flows

This study assesses different turbulence modeling approaches for simulation of two-phase coaxial annular swirling jet flows. The problem selected from literature involves an analytical inlet profile for an annular liquid sheet sandwiched between two coaxial annular gaseous jets. The liquid-gas interface is resolved using the volume-of-fluid (VOF) model with continuum surface force approximation. 3D unsteady Reynolds averaged Navier-Stokes simulations using up to 8.4 million grid cells and 64 HPC cores are conducted using the Fluent 17.2 software to obtain transient multiphase CFD data for this problem. Different turbulence models explored include the k-epsilon RNG with swirl modification, the Reynolds stress model (RSM), and RSM with scale adaptive simulations (RSM-SAS). Comparisons with the direct numerical results from literature suggest that the scale-adaptive simulation using RSM-SAS approach better predicts the onset of instability, liquid jet column collapse, jet mixing, vortex breakup, and the overall characteristics of this flow.