Annular centrifugal extractors are widely used in industry for the extraction of radioactive fuel in nuclear fuel reprocessing, emulsion polymerization, crystallization, and other processes. It is a single compact unit, consisting of a mixer and a settler, that operates under the action of centrifugal force. Although the equipment is widely used, the design procedures are still empirical due to the complexity of fluid mechanics in the mixer and settler zones. For the development of rational and reliable design procedures, it is important to understand the flow patterns in these zones. This article presents a hydrodynamic study of flow within the rotor using computational fluid dynamics (CFD) with standard k-?, SST k-?, and RSM turbulence models. The rotor diameter was varied over a wide range of 125 to 375 mm and the rotor speed over 20 to 175 rad/s. A comparison is presented between the CFD predictions and experimental measurements reported in the published literature. The hydraulic performance of a rotor as a centrifugal pump is presented in terms of head (discharge pressure), capacity, and power consumption. The flow pattern in the suction and settling zones of the contactor is presented with streamlines, static pressure distribution, and velocity profiles.