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COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Effect of the flow macro-scale on the effective drag coefficient in gas-solid riser flows
Submission Author:
Seyed Reza Amini Niaki , SP , Brazil
Co-Authors:
Seyed Reza Amini Niaki, Joseph Mouallem, Norman Chavez Cussy, Gabriel Jonatas Santos Netzlaff, Christian Milioli, Fernando Milioli
Presenter: Seyed Reza Amini Niaki
doi://10.26678/ABCM.COBEM2017.COB17-0182
Abstract
Large scale simulation of gas-particle riser flows with two-fluid modeling, where gas and particulate are both treated as interpenetrating continuum phases, does require closure models to deal with sub grid filtered parameters such as effective stresses and interphase interactions. The topology of a riser flow comprises coherent structures of particulate that develop in a multitude of space and time scales, which are qualitatively well captured by the current two-fluid formulations. Quantitative accuracy, on the other hand, is still out of reach mostly due to the lack of more accurate sub-grid models. One among the sub-grid models that require enhancement is that for the effective interphase drag. Suitable models for the effective drag have been recently derived from results of highly resolved simulations with two-fluid modeling, which account for sub-grid flow heterogeneities, but disregard any macro-scale impact. In this work it is showed that, in addition to usual sub-grid filtered parameters, effective drag modeling also requires correlation to macro-scale effects. It is showed that the domain averages solid volume fraction and the domain average gas flow Reynolds number stand as relevant macro-scale parameters to be accounted for if higher modeling accuracy is pursued.
Keywords
gas-particle flow, Two Fluid Model, Fluidization, macro-scale, effective drag, MFIX
