Hydrodynamics of airlift loop reactors was studied in detail experimentally and theoretically. An internal airlift loop reactor was designed and set up for this study. An instrumentation system based on the electrochemical method was adapted to measure local gas holdup and liquid velocity. A two-dimensional two-fluid model based on the first principles was established and implemented to model the flow in airlift loop reactors. A corrected turbulent model was incorporated in the simulation. The shear rate, shear stress and energy dissipation are evaluated from the flow field. The numerically predicted results and experimental data obtained from this work as well as these reported in literature are analyzed and compared.