The hydrodynamics of a two-dimensional gas-solid fluidized bed reactor were studied experimentally and computationally. Computational fluid dynamics (CFD) simulation results from a commercial CFD software package, Fluent, were compared to those obtained by experiments conducted in a fluidized bed containing spherical glass beads of 250-300 mu m in diameter. A multifluid Eulerian model incorporating the kinetic theory for solid particles was applied in order to simulate the gas-solid flow. Momentum exchange coefficients were calculated using the Syamlal-O'Brien, Gidaspow, and Wen-Yu drag functions. The solid-phase kinetic energy fluctuation was characterized by varying the restitution coefficient values from 0.9 to 0.99. The modeling predictions compared reasonably well with experimental bed expansion ratio measurements and qualitative gas-solid flow patterns. Pressure drops predicted by the simulations were in relatively close agreement with experimental measurements at superficial gas velocities higher than the minimum fluidization velocity, U-mf. Furthermore, the predicted instantaneous and time-average local voidage profiles showed similarities with the experimental results. Further experimental and modeling efforts are required in a comparable time and space resolutions for the validation of CFD models for fluidized bed reactors. (c) 2005 Elsevier Ltd. All rights reserved.