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Two- and three-dimensional hydrodynamic modeling of a pseudo-2D turbulent fluidized bed with Geldart B particle

Author:
Chang, Jian, Wu, Zejun, Wang, Xin, Liu, Wenyi
Source:
Powder technology 2019 v.351 pp. 159-168
ISSN:
0032-5910
Subject:
fluidized beds, hydrodynamics, hydrologic models, powders, prediction
Abstract:
This study presents a comprehensive comparision between 2D and 3D hydrodynamic modeling of a pseudo-2D turbulent fluidized bed with Geldart B particle. Based on the Euler-Euler approach and the EMMS-based drag model, 2D/3D CFD models are established, their sensitivities to the restitution coefficient and the specularity coefficient are analyzed, and the 2D/3D hydrodynamic simulations are performed and compared. The simulation results show that 3D simulations are more sensitive to the restitution coefficient and the specularity coefficient than 2D simulations. At the beginning of fluidization process, 2D simulation predicts greater bubble size and higher bed expansion than 3D simulation; as a complete fluidization is achieved, 2D model exhibits higher solid concentrations in the middle transition and the upper dilute-phase regions; the fluidization process in the 2D simulation develops more quickly than that in the 3D computation. Both the 2D and 3D models could capture the global flow behavior in the bottom dense-phase region of the turbulent fluidized bed reasonably. In the middle and upper regions, however, the 2D model overestimates the solid concentration and particle velocity while the 3D simulation gives better hydrodynamic prediction. For the present pseudo-2D turbulent fluidized bed with Geldart B particle, the bottom dense-phase region resembles 2D flow and 2D simulations may be adequate; however, the middle and upper regions exhibit 3D flow and full 3D simulations are needed.
Agid:
6373969