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Numerical simulation of bubbling fluidization using a local bubble‐structure‐dependent drag model
Author(s) -
Du Shaohua,
Liu Lijun
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.23412
Subject(s) - drag , fluidization , mechanics , drag coefficient , bubble , two fluid model , flow (mathematics) , interphase , local bubble , thermodynamics , physics , materials science , fluidized bed , genetics , quantum mechanics , interstellar medium , galaxy , biology
The meso‐scale flow structure in gas‐solid bubbling fluidization has significant effects on hydrodynamics and interphase heat and mass transfer. However, traditional homogeneous drag models neglect the meso‐scale structure and fail to yield a reasonable prediction of the hydrodynamics in bubbling fluidization. In this study, the gas‐solid system within a grid cell combines three subsystems in order to take the meso‐scale structure into account. Based on this resolution, a local bubble‐structure‐dependent drag model is established. In addition, a homogeneous interphase drag correlation based on direct numerical simulation is coupled with the novel drag model to describe the interphase interaction when the flow structure is homogeneous. Then, the proposed drag model is incorporated into two fluid models to simulate the hydrodynamics in bubbling fluidization with Geldart A and A/B particles. The predicted profiles of the time‐averaged solid volume fraction are compared with experimental data to validate the effectiveness of the novel drag model. The results show that the average relative error of the solid volume fraction is reduced from over 30 to ∼10 % by replacing homogeneous drag models with the novel drag model.