Conveying vessels, which are widely used in pneumatic systems, feature gas-solid flow with intensive interphase interactions and complex flow patterns. In this study, a two-fluid model was used to simulate flow behaviors in an experimental vessel. To model the gas phase, a k-epsilon turbulent model and the particle phase kinetic theory of granular flow were used. Three hydraulic stages were indicated: the rising, static and declining phases. Flow regimes similar to a spouted bed were formed near the wall, which became increasingly stable over time. Unstable flow regimes that consisted of bubbles and slugs were formed near the central part of the vessel. The velocity distributions of the gas and particles, the pressure profile and the secondary flow are described. A fitted curve of the output and input was obtained, and the influences of inlet conditions, such as velocity and pressure, were also investigated. (C) 2012 Elsevier B.V. All rights reserved.