The complex task of describing computationally two-phase turbulent flows in aerated stirred-tank reactors was overcome by proposing that the gas flow rate in the hollow impeller can be estimated from single-phase flow simulations of the liquid phase in the reactor: the pressure at the impeller surface obtained from liquid phase simulations can be related to the gas induction rate. A commercial lab-scale reactor with a radial six-bladed hollow impeller was chosen for the study. To validate the presented methodology, the induced gas flow rate was measured experimentally from the tracking of the position of bubbles in a dynamic sequence of flow images. Notwithstanding the simplifications assumed in the presented CFD methodology, good agreement has been obtained between numerical results and experiments.