In multiphase operations, such as liquid-liquid or gas-liquid, systems, the interfacial area affects the interfluid heat, mass and momentum transfer and ultimately, the overall equipment performance. To better understand the mixing process, we developed a multi-fluid model that predicts interfacial area for kerosene-water mixtures in co-current jet mixers. The model has ensemble-averaged conservation equations for each fluid and includes a transport equation, derived from an overall energy balance, for the-interfacial area concentration. In the model, the mechanical energy of, the continuous phase creates interfacial area. Comparing, the final, one-dimensional model to experimental data proved the model is accurate. Over 93% of the, calculated and experimental data obtained from 0.027 inch and 0.0141 inch diameter co-current jet mixers compared within 15%.