This article describes the experimental and numerical characterization of capillary fuel injection, atomization, and dispersion of liquid fuel in a co-flowing air stream inside a single venturi tube. The experimental techniques used are all laser-based A phase Doppler particle analyzer (PDPA) was used to characterize the atomization process, and planar laser-induced fluorescence (PLIF) was used to visualize the breakup and atomization process of the capillary fuel spray. The PLIF experiments confirmed the domination of aerodynamic breakup mechanism in and the influence of gaseous vortical structures of various scales on the atomization process of capillary fuel spray. The PLIF images displayed a smooth liquid jet surface near the fuel tube exit, with a rough, perturbed surface developing gradually. At low relative velocities, it was observed that the initial dilational waves on the jet surface were followed by asymmetric and sinuous waves before they evolved into curling liquid ligaments and/or droplets, as the relative velocities increased. The advantages of venturi nozzle are demonstrated in this article in terms of better atomization, more uniform fuel-air distribution, compared,vith straight-tube nozzles and free jets. A modified version of KIVA-II was used to simulate the entire spray process, including breakup and atomization. It was concluded that the multidimensional spray calculation can be used as a design tool only if care is taken in the modeling of breakup and wall impingement processes.