CFD simulation of smooth and T-abrupt exits in circulating fluidized bed risers--颗粒学报PARTICUOLOGY

Wu, X., Jiang, F., Xu, X., & Xiao, Y. (2010). CFD simulation of smooth and T-abrupt exits in circulating fluidized bed risers. Particuology, 8(4), 343-350. https://doi.org/10.1016/j.partic.2010.01.007

CFD simulation of smooth and T-abrupt exits in circulating fluidized bed risers

Xuezhi Wu ^{a b *}, Fan Jiang ^a, Xiang Xu ^a, Yunhan Xiao ^a

a Key Laboratory of Advanced Energy and Power, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
b Graduate University of the Chinese Academy of Sciences, Beijing 100049, China

10.1016/j.partic.2010.01.007

Volume 8, Issue 4, August 2010, Pages 343-350

Received 22 July 2009, Revised 9 November 2009, Accepted 24 January 2010, Available online 3 July 2010.

E-mail: wuxuezhi06@mails.gucas.ac.cn

Highlights

Abstract

Gas–solid flow in circulating fluidized bed (CFB) risers depends not only on operating conditions but also on exit configurations. Few studies investigated the effects of exit configurations on flow structure using computational fluid dynamics (CFD). This paper provides a 2D two-fluid model to simulate a cold bench-scale square cross-section riser with smooth and T-abrupt exits. The drag force between the gas and solid phases plays an important role in CFD. Since the drag force model based on homogeneous two-phase flow, such as the Wen-Yu correlation, could not capture the heterogeneous structures in gas–solid flow, the structure-dependent energy-minimization multi-scale (EMMS) drag force model (Wang, Ge, & Li, 2008), applicable for Geldart B particles (sand), was integrated into the two-fluid model. The calculated axial solids hold-up profiles were respectively exponential curve for smooth exit and C-shaped curve for T-abrupt exit, both consistent with experimental data. This study once again proves the key role of drag force in CFD simulation and also shows the validity of CFD simulation (two-fluid model) to describe exit effects on gas–solid flow in CFB risers.

Graphical abstract

Keywords

T-abrupt exit; Smooth exit; Gas–solid flow; CFB; EMMS drag force model

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