This paper presents a three-dimensional Eulerian–Eulerian modeling approach to predict the turbulent flow in an aerated bioreactor. The standard \(k-\varepsilon \) model is employed to simulate the hydrodynamics of the two-phase flow. The turbulence of the gas phase has been taken in consideration through the bubble induced turbulence source terms. To compute residence time distributions (RTD), another equation for the transport of a passive tracer is solved using the previously simulated flow. A tracer pulse is introduced at the inlet and is tracked at the water exit by simulating its concentration. Results were compared with the experimental measurements when the liquid and gas flow rates are respectively equal to 3.6 and 15 L.min−1. It is found that the turbulence model of standard \(k-\varepsilon \) underestimated the dispersion in the reactor but accurately predicted the residence time distribution.