Numerical investigation of the grid spatial resolution and the anisotropic character of EMMS in CFB multiphase flow

Atsonios, K; Nikolopoulos, A; Karellas, S; Nikolopoulos, N; Grammelis, P; Kakaras, E

dc.contributor.author	Atsonios, K	en
dc.contributor.author	Nikolopoulos, A	en
dc.contributor.author	Karellas, S	en
dc.contributor.author	Nikolopoulos, N	en
dc.contributor.author	Grammelis, P	en
dc.contributor.author	Kakaras, E	en
dc.date.accessioned	2014-03-01T01:36:31Z
dc.date.available	2014-03-01T01:36:31Z
dc.date.issued	2011	en
dc.identifier.issn	0009-2509	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/21321
dc.subject	CFB	en
dc.subject	CFD	en
dc.subject	EMMS	en
dc.subject	Grid	en
dc.subject	Multiphase flow	en
dc.subject	PDD	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.other	CFB	en
dc.subject.other	Circulating fluidized bed combustor	en
dc.subject.other	Complex particles	en
dc.subject.other	Computational costs	en
dc.subject.other	Drag forces	en
dc.subject.other	EMMS	en
dc.subject.other	Energy minimization	en
dc.subject.other	Explicit modeling	en
dc.subject.other	Grid	en
dc.subject.other	Grid density	en
dc.subject.other	In-depth understanding	en
dc.subject.other	Inert materials	en
dc.subject.other	Interphase momentum exchange	en
dc.subject.other	Isothermal conditions	en
dc.subject.other	Multiscales	en
dc.subject.other	Numerical accuracy	en
dc.subject.other	Numerical approaches	en
dc.subject.other	Numerical investigations	en
dc.subject.other	Numerical results	en
dc.subject.other	PDD	en
dc.subject.other	Real time	en
dc.subject.other	Simulation result	en
dc.subject.other	Spatial resolution	en
dc.subject.other	Spatio-temporal	en
dc.subject.other	Uniform grids	en
dc.subject.other	Anisotropy	en
dc.subject.other	Computer simulation	en
dc.subject.other	Drag	en
dc.subject.other	Fluidization	en
dc.subject.other	Fluidized bed combustion	en
dc.subject.other	Fluidized bed combustors	en
dc.subject.other	Fluidized bed process	en
dc.subject.other	Fluidized beds	en
dc.subject.other	Investments	en
dc.subject.other	Multiphase flow	en
dc.subject.other	Numerical methods	en
dc.subject.other	Optimization	en
dc.subject.other	Mathematical models	en
dc.title	Numerical investigation of the grid spatial resolution and the anisotropic character of EMMS in CFB multiphase flow	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.ces.2011.05.024	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.ces.2011.05.024	en
heal.language	English	en
heal.publicationDate	2011	en
heal.abstract	During the last years, considerable efforts have been made for the optimization of numerical methods simulating the operation of the Circulating Fluidized Bed Combustors (CFBC), which imply both the accuracy increase and the computational cost decrease. A foremost goal is the efficient description of its operation under isothermal conditions and the in-depth understanding of the governing complex multiphase flow mechanisms. Grid construction and the calculation of the drag force experienced by the inert material in the two-phase flow are two important parameters for the optimization of the numerical approaches in the case of CFB simulation. The aim of the present investigation is to investigate both the effect of grid density distribution on simulation results and the validity of an anisotropic approach for the drag force calculation through an Energy Minimization Multi-Scale (EMMS) scheme. Grid density distribution is found to affect the numerical accuracy and the real time of simulations. Uniform grid density distribution is found to be the most efficient choice in terms of balance between computational cost and numerical accuracy. On the other hand, EMMS scheme improves the efficiency of detecting complex particle structures (clusters) without an explicit modeling of these spatio-temporal formations. Moreover, applying EMMS scheme only for calculation of the z-component of drag force yielded better numerical results compared to a constant interphase momentum exchange coefficient for all the three directions. (C) 2011 Elsevier Ltd. All rights reserved.	en
heal.publisher	PERGAMON-ELSEVIER SCIENCE LTD	en
heal.journalName	Chemical Engineering Science	en
dc.identifier.doi	10.1016/j.ces.2011.05.024	en
dc.identifier.isi	ISI:000292190400026	en
dc.identifier.volume	66	en
dc.identifier.issue	17	en
dc.identifier.spage	3979	en
dc.identifier.epage	3990	en