Accurate level set method for simulations of liquid atomization

Computational fluid dynamics is an efficient numerical approach for spray atomization study, but it is challenging to accurately capture the gas–liquid interface. In this work, an accurate conservative level set method is introduced to accurately track the gas–liquid interfaces in liquid atomization. To validate the capability of this method, binary drop collision and drop impacting on liquid film are investigated. The results are in good agreement with experiment observations. In addition, primary atomization (swirling sheet atomization) is studied using this method. To the swirling sheet atomization, it is found that Rayleigh–Taylor instability in the azimuthal direction causes the primary breakup of liquid sheet and complex vortex structures are clustered around the rim of the liquid sheet. The effects of central gas velocity and liquid–gas density ratio on atomization are also investigated. This work lays a solid foundation for further studying the mechanism of spray atomization.

Graphical AbstractIn the front of liquid sheet, ligaments and droplets formed undergo involute movement, which are controlled by inertial force, centrifugal force, aerodynamic force and surface tension. The local flow patterns, associated with velocity gradient, have an effect on the deformation and movements of ligaments and droplets. The interface and vortex structures characterized by Q criterion are shown in this figure. It is clear to see that torus-shape vortex structures warp the droplet, the filamentary vortex tubes are along with the rim of liquid sheet and a large number of vortex tubes are aligned with axis.Figure optionsDownload as PowerPoint slide