The objective of this study is to analyze the solid and fluid flow behaviors inside a rotary drum using computational fluid dynamics (CFD). The CFD model developed was based on an Eulerian-Eulerian multiphase flow approach. The capability of the multiphase CFD model to predict the transverse and axial solid flow patterns, the fluid flow profile, and particle residence time was assessed. The model was used to study the effects of drum rotational speed, filling degree, feed rate, and drum inclination angle. It was verified using experimental results of particle and fluid velocities and residence time. The experiments were conducted on pilot scale rotary drums. As could,be proved by measured and simulated results, the particle flow near the bed surface exerted a strong entrainment effect on the transverse air flow in the proximity of the bed surface. The study demonstrated the capability of the multiphase CFD model to predict the particle and fluid flow behaviors inside a rotary drum simultaneously. (C) 2016 Elsevier B.V. All rights reserved.