The Cascade Atomization and Drop Breakup (CAB) model has been originally developed for pressure atomizers. In this study, the CAB model is modified to accommodate the atomization of low-pressure, air-assist atomizers. The modifications include the first breakup which is modeled by estimating theWeber number due to the increased liquid-gas relative velocity caused by the air flow. This breakup depends on whether the Weber number is in the catastrophic, stripping or bag breakup regime. The second modification includes a change in the product drop distributions, namely, instead of a uniform distribution, as used in the original CAB model, a X-squared
distribution with the same average drop size is assumed. The model changes are validated with experimental data obtained by means of two different air-assist atomizers using an oil-in-water emulsion. The simulations are performed with a modified version of the KIVA-3 CFD code; they show good agreement with the experiments
