Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Effect of the flow macro-scale on the effective stresses in gas-solid riser flows
Submission Author:
Joseph Mouallem , SP , Brazil
Co-Authors:
Joseph Mouallem, Seyed Reza Amini Niaki, Norman Chavez Cussy, Gabriel Jonatas Santos Netzlaff, Christian Milioli, Fernando Milioli
Presenter: Joseph Mouallem
doi://10.26678/ABCM.COBEM2017.COB17-0179
Abstract
The two-fluid modeling approach usually applied in large scale simulation of gas-particle riser flows requires closure models to deal with sub-grid filtered parameters such as effective stresses and interphase interactions. The very heterogeneous riser flows are characterized by a continuous intense formation and dissipation of particulate coherent structures. In spite of this complex topology, two-fluid modeling, where fluid and particulate are treated as inter- penetrating continua, does provide qualitatively correct solutions. The cur- rent approaches, however, still cannot deliver quantitative accuracy, mostly owing to the lack of more accurate sub-grid filtered models. The effective stresses in both the phases are among the sub-grid filtered parameters for which model enhancement is required. Models for effective stresses have been recently derived from filtering over results of highly resolved simulations with two-fluid modeling. Those models account for sub-grid flow heterogeneities, but disregard any macro-scale topology effect. This work shows that effective stresses modeling also requires correlation to macro-scale effects, the domain average solid volume fraction and the domain average gas flow Reynolds number being relevant macro-scale parameters to be accounted for.
Keywords
multiphase flow, Gas-solid flow, Computational fluid dynamics (CFD), TFM, gas-particle flow, Two Fluid Model, fluidized bed, Risers, MFIX
