PEPT and discrete particle simulation study of spout-fluid bed regimes

The results of a combined experimental and simulation study on the flow regimes that can be encountered during spout-fluid bed operation are reported. A regime map for a three-dimensional (3D) spout-fluid bed was composed, employing spectral analysis of pressure drop fluctuations and fast video recordings. In addition, 3D Euler-Lagrangian computations were performed to assess the capability of the model to reproduce the experimentally observed flow regimes. Spectral analysis of pressure drop fluctuations revealed that for most investigated regimes the model is able to predict the appropriate regime. The frequency at which the largest power is found is overpredicted by the model in most cases. The remaining differences between the simulated and the experimentally observed bed behavior are most probably related to the representation of the effective fluid-particle interaction in the model, which relies on local spatial homogeneity. The simulation results were compared with velocity maps determined from particle trajectories acquired using positron emission particle tracking. The model accurately reproduces measured particle velocities, including their root mean square, for all investigated conditinnx and is therefore able to capture the details of the particle flow in various flow regimes. © 2008 American Institute of Chemical Engineers.