It is a key step to understand the bubbling behavior in order to quantitatively describe the flow and transfer behavior in bubble columns. Compared with two-dimensional simulation, three-dimensional simulation is able produce relatively realistic results of bubble behavior. Based on two-dimensional numerical studies on single bubbling behavior, three-dimensional numerical simulations on bubble formation, growth, detachment, rise motion with one-, two- and four-orifice and interaction of two parallel bubbles in bubble columns were investigated using the volume of fluid (VOF) model on the software platform of Fluent 6.3, and the results were validated with the experimental observations. Effects of fluid physical properties, operation conditions and orifice size on bubble behavior were numerically analyzed besides the interactions of parallel bubbles in bubble columns and the variation rules on bubble formation and rising behavior were obtained. (C) 2012 Elsevier Ltd. All rights reserved.