Fluidization of fine powders in fluidized beds with an upward or a downward air jet--颗粒学报PARTICUOLOGY

Hong, R., Ding, J., & Li, H. (2005). Fluidization of fine powders in fluidized beds with an upward or a downward air jet. China Particuology, 3(3), 181-186. https://doi.org/10.1016/S1672-2515(07)60083-9

Fluidization of fine powders in fluidized beds with an upward or a downward air jet

Ruoyu Hong ^{a b *}, Jianmin Ding ^c, Hongzhong Li ^b

a Department of Chemistry and Chemical Engineering, Soochow University, Suzhou 215006, P. R. China
b Multi-Phase Reaction Laboratory, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080, P. R. China
c IBM, HYDA/050-3 C202, 3605 Highway 52 North, Rochester, MN 55901, USA

10.1016/S1672-2515(07)60083-9

Volume 3, Issue 3, June 2005, Pages 181-186

Received 15 September 2004, Accepted 7 March 2005, Available online 27 November 2007.

E-mail: rhong@suda.edu.cn

Highlights

Abstract

The hydrodynamic behavior of fine powders in jet-fluidized beds was studied numerically and experimentally. The starting point of numerical simulation was the generalized Navier-Stokes (N-S) equations for the gas and solids phases. The κ-ɛ turbulence model was used for high-speed gas jets in fluidized beds. Computation shows that a suitable turbulence model is necessary to obtain agreement between the simulation and literature experimental data for a high-speed gas jet. The model was applied to simulating the fluidization of fine powders in fluidized beds with an upward or a downward air jet. An empirical cohesion model was obtained by correlating the cohesive force between fine particles using a cohetester. The cohesion model was embedded into the two-fluid model to simulate the fluidization of fine powders in two-dimensional (2-D) beds. To study the fluidization behavior of fine and cohesive powders with a downward jet, experiments were performed in a 2-D bed. Agreement between the computed time-averaged porosity and measured data was obtained. With an upward jet in the bed center, the measured and computed porosities show a dilute central core, especially at very high jet velocities. Based on our experiments and computations, a downward jet located inside the bed is recommended to achieve better mixing and contacting of gas and solids.

Graphical abstract

Keywords

fluidization; jet; fine powder; two-fluid model

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