Numerical simulation of the initial destabilization of an air-blasted liquid layer

Numerical simulations of a planar air/water air-blast atomization are performed using an in-house multiphase Navier–Stokes solver which uses a semi-Lagrangian geometric volume of fluid method to track the position of the interface. This solver conserves mass exactly and mitigates momentum and kinetic energy conservation errors. Excellent agreement with recent experiments is obtained when comparing physical quantities, such as the liquid cone length, maximum wave frequency and spatial growth rate of the primary instability. The inclination of the gas inflow, which mimics the slope of the separator plate, is shown to enhance the primary atomization. A three-dimensional large-eddy simulation, run using physically correct air/water parameters, is used to provide the statistics of the flow. The gas layer is laminar close to the entrance and becomes turbulent at positions further downstream. The liquid wave crests expand in thin sheets, which break into secondary droplets, as observed in experiments.