Investigation of Solid Hold-Up in a Gas-Solid Fluidized Bed at High Gas Velocities by CFD

Document Type : Research Article

Authors

1 Faculty of Engineering, University of Ilam, Ilam, I.R. IRAN

2 Department of Chemical Engineering, University of Sistan and Baluchestan, Zahedan, I.R. IRAN

Abstract

Simulation results of bubbling gas-solid fluidized bed using two-fluid model integrating the kinetic theory of granular flow are presented. Results of solid hold-up at different axial locations and radial directions are shown. Simulations are performed at high gas velocities. Particle motion and bubble behavior at two gas velocities of 0.35 and 0.9856 m/s in the bed are predicted and compared with the experimental data. Predicted results show that the gas velocity and ratio of the static bed height to width of the bed are important parameters for prediction of solid particles motions in a bubbling fluidized bed. Current work indicates the sensitivity of the CFD results to the drag model. Arastoopour’s drag model is the best choice for this study.At high gas velocity of 2.1824 m/s the standard k-e turbulent model and laminar models are compared. In general, the model predictions are in a good agreement with the experimental data. Current model reduces simulation’s errors compared with previous works. The minimum error is 8 % and the maximum error is 13.7 % in lower and upper part of the bed in radial direction, respectively.In addition, the error in axial direction is 4.5 %. The gas velocity values has a significant effect in solid particles motions.

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References

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