In this paper, a numerical simulation of an air-blast atomizer using OpenFOAM software is performed to evaluate the effects of geometrical parameters and flow conditions on spray characteristics. The method used in this numerical simulation is discrete droplets tracking-based Eulerian-Lagrangian approach. In the primary breakup of liquid jet modeling, the Rosin-Rammler distribution function and in modeling the secondary breakup phase, the Kelvin-Helmholtz, Rayleigh-Taylor (KHRT), and the TAB models are used and compared. The simulation results show that the KHRT model has reasonable prediction of atomization characteristics and, at a specific Weber number, SMD increases with raising liquid port diameter. However, in high Weber number, this parameter has little effect on SMD. In addition, gas liquid injection angle has an insignificant effect on the penetration depth of spray, while increasing the liquid port diameter decreases it considerably. (C) 2017 Elsevier Masson SAS. All rights reserved.