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Effects of drag force correlations on the mixing and segregation of polydisperse gas‐solid fluidized bed by CFD‐DEM simulation
Author(s) -
Zhang Yong,
Li Yanjiao,
Gao Zhonglin,
Li Guofeng,
Zhao Yuemin,
Duan Chenlong,
Dong Liang
Publication year - 2019
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.23421
Subject(s) - drag , fluidization , fluidized bed , ternary operation , mechanics , thermodynamics , drag coefficient , computational fluid dynamics , mixing (physics) , physics , materials science , quantum mechanics , computer science , programming language
The dense gas‐solid fluidized beds with polydisperse particles are commonly encountered in the chemical industry. In this study CFD‐DEM simulation of ternary particles in a bubbling fluidized bed were studied to assess four polydisperse drag correlations, using experimental data from Olaofe et al.[1] as the benchmark. The following was shown: (i) the drag force models of Sarkar et al.,[2] Cello et al.,[3] and Rong et al.[4] can correctly predict the minimum fluidization velocity of the mixture of ternary particles, but Gidaspow's model significantly over‐predicts this;[5] (ii) no model can accurately predict the experimental segregation degree at different gas velocity, but for the cases that were studied, the models from Cello et al.[3] and Sarkar et al.[2] correlated relatively better with Olaofe et al.'s[1] experimental data than others; and (iii) detailed force analysis found that the collisional force of each type of particles is on average not equal to zero, especially for a system that is strongly segregated. In addition, the differences of drag force for different sizes of particles are the key reason for size segregation rather than pressure gradient force.