CFD–DEM study of effect of bed thickness for bubbling fluidized beds--颗粒学报PARTICUOLOGY

Li, T., Gopalakrishnan, P., Garg, R., & Shahnam, M. (2012). CFD–DEM study of effect of bed thickness for bubbling fluidized beds. Particuology, 10(5), 532–541. https://doi.org/10.1016/j.partic.2012.02.006

CFD–DEM study of effect of bed thickness for bubbling fluidized beds

Tingwen Li ^{a b *}, Pradeep Gopalakrishnan ^{a c}, Rahul Garg ^{a b}, Mehrdad Shahnam ^a

a National Energy Technology Laboratory, Department of Energy, Morgantown, WV 26505, USA
b URS Corporation, Morgantown, WV 26505, USA
c Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061, USA

10.1016/j.partic.2012.02.006

Volume 10, Issue 5, October 2012, Pages 532-541

Received 16 September 2011, Revised 4 January 2012, Accepted 20 February 2012, Available online 25 April 2012.

E-mail: tingwen.li@ur.netl.doe.gov

Highlights

► The effect of bed thickness in rectangular fluidized beds is investigated via the CFD–DEM simulations of small-scale systems.

► Transition from 2D flow to 3D flow occurs within the range of 20d_p–40d_p.

► Wall effect cannot be neglected in CFD simulation of pseudo-2D beds.

Abstract

The effect of bed thickness in rectangular fluidized beds is investigated through the CFD–DEM simulations of small-scale systems. Numerical results are compared for bubbling fluidized beds of various bed thicknesses with respect to particle packing, bed expansion, bubble behavior, solids velocities, and particle kinetic energy. Good two-dimensional (2D) flow behavior is observed in the bed having a thickness of up to 20 particle diameters. However, a strong three-dimensional (3D) flow behavior is observed in beds with a thickness of 40 particle diameters, indicating the transition from 2D flow to 3D flow within the range of 20–40 particle diameters. Comparison of velocity profiles near the walls and at the center of the bed shows significant impact of the front and back walls on the flow hydrodynamics of pseudo-2D fluidized beds. Hence, for quantitative comparison with experiments in pseudo-2D columns, the effect of walls has to be accounted for in numerical simulations.

Graphical abstract

Keywords

Bubbling fluidized bed; CFD; Wall effect; Discrete element method; Pseudo-2D; Flow hydrodynamics

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