A two-dimensional mathematical model has been developed to describe annular electrochemical reactor performance. Multiple electrochemical reactions of copper electrowinning from a chloride solution were evaluated to illustrate the usage of the model. The simulation includes the mass transport of ionic species and the associated electrochemical kinetics under the laminar fluid flow condition. The model predicts current distributions on the electrodes, conversion per pass (CPP), selectivity of copper as a function of the applied potential, residence time, and anode to cathode diameter ratio.