Generalized Boltzmann kinetic theory for EMMS-based two-fluid model | |
Zhao, Bidan1,2; Li, Shuyue1,3; Wang, Junwu1 | |
刊名 | CHEMICAL ENGINEERING SCIENCE |
2016-12-15 | |
卷号 | 156期号:DEC页码:44-55 |
关键词 | Fluidization Multiphase flow Pseudo-Reynolds stress Mesoscale structures Cluster Kinetic theory |
ISSN号 | 0009-2509 |
英文摘要 | It has long been recognized that the solid particles in circulating fluidized bed risers are distributed heterogeneously in the form of clusters. In response to this fundamental phenomenon, an EMMS-based two-fluid model has been developed recently from the viewpoint of continuum mechanics, however, its microscopic foundation remains unknown. In this study, the statistical mechanics foundation of EMMS-based two-fluid model was presented using generalized Boltzmann kinetic theory. With respect to the gas phase, a new method was developed by considering the fluctuations at different scales simultaneously, with which we can for the first time derive the correct governing equations of gas phase via kinetic theory, in the sense that both the molecular stress and the Reynolds (or pseudo-Reynolds) stress can be obtained simultaneously, whereas all previous kinetic theory analyses failed to predict the appearance of Reynolds (or pseudo-Reynolds) stress in the momentum conservation equation of gas phase due to the assumption of uniform structure, although it is physically always existent no matter how small the Reynolds number is. In case of particle phase, the generalized Boltzmann equation considering the spatio-temporal variation of the volume, density and velocity of clusters was firstly derived, a set of macroscopic transport equations was then derived in different phase spaces. It was shown that the governing equations of dense phase in the EMMS-based two-fluid model derived from continuum mechanics viewpoint corresponds to the macroscopic transport equations at (r, t) space. Therefore, present study launches a solid microscopic foundation of EMMS-based two-fluid model. Finally, CFD simulations have been carried out to validate EMMS-based two-fluid model and to study the effect of gas phase pseudo-turbulence. (C) 2016 Elsevier Ltd. All rights reserved. |
WOS标题词 | Science & Technology ; Technology |
类目[WOS] | Engineering, Chemical |
研究领域[WOS] | Engineering |
关键词[WOS] | CIRCULATING FLUIDIZED-BED ; GAS-SOLID FLOW ; FLUX CFB RISER ; CONSTITUTIVE RELATIONS ; TURBULENT FLOWS ; 2-PHASE FLOW ; HIGH-DENSITY ; SIMULATION ; VELOCITY ; DRAG |
收录类别 | SCI |
语种 | 英语 |
WOS记录号 | WOS:000387112500005 |
内容类型 | 期刊论文 |
源URL | [http://ir.ipe.ac.cn/handle/122111/21647] |
专题 | 过程工程研究所_多相复杂系统国家重点实验室 |
作者单位 | 1.Chinese Acad Sci, State Key Lab Multiphase Complex Syst, Inst Proc Engn, Beijing 100190, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.China Univ Petr, State Key Lab Heavy Oil Proc, Beijing 102249, Peoples R China |
推荐引用方式 GB/T 7714 | Zhao, Bidan,Li, Shuyue,Wang, Junwu. Generalized Boltzmann kinetic theory for EMMS-based two-fluid model[J]. CHEMICAL ENGINEERING SCIENCE,2016,156(DEC):44-55. |
APA | Zhao, Bidan,Li, Shuyue,&Wang, Junwu.(2016).Generalized Boltzmann kinetic theory for EMMS-based two-fluid model.CHEMICAL ENGINEERING SCIENCE,156(DEC),44-55. |
MLA | Zhao, Bidan,et al."Generalized Boltzmann kinetic theory for EMMS-based two-fluid model".CHEMICAL ENGINEERING SCIENCE 156.DEC(2016):44-55. |
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