Aerodynamic Blockage Effect on the Spray Characteristics of a Liquid Jet Atomized by Crossflowing Air

Abstract

We study the role of jet-induced wake and vortical structures on the transport of drops formed by mass stripping and jet breakup due to crossflowing gas. Gas and liquid phases are computed as a single-fluid Eulerian continuum by tracking the gas-liquid interface with a Volume of Fluid (VOF) methodology. Droplets (numerically treated as parcels) are injected at fixed locations near the jet, based on near-field experimental observations. Their trajectories are evolved in time so that patterns of volumetric flux, axial velocity and Sauter Mean Diameter (SMD) can be compared with experimental measurements in the far field. We find that vortical structures due to aerodynamic blockage are maintained up to several orifice diameters downstream of the jet, affecting the droplet trajectories and ultimately the spray distribution. We also demonstrate that an interface-tracking algorithm for capturing the jet bulk features allows the prediction of far field spray characteristics when coupled to a simple set of rules for spray distribution after primary breakup.