A numerical simulation analysis of the effect of the interface drag function on cluster evolution in a CFB riser gas-solid flow

Brazilian Journal of Chemical Engineering

L. C. Gómez¹  F. E. Milioli¹ 

[1] ,USP Escola de Engenharia de São Carlos Núcleo de Engenharia Térmica e FluidosSão Carlos SP ,Brasil

关键词: coherent structures;    clusters;    drag function;    numerical simulation;    gas-solid flow;    circulating fluidized bed;   

DOI  :  10.1590/S0104-66322004000400006

来源: SciELO

【 摘 要 】

The dynamics of formation, dissipation and breaking of coherent structures in the riser gas-solid flow of a circulating fluidized bed (CFB) are evaluated by numerical simulation. The simulation is performed using the MICEFLOW code, which includes IIT's two-fluid hydrodynamic model B. The methodology for cluster characterization is used from Sharma et al. and is based on determination of four characteristics, average lifetime, average volumetric fraction of solid, existence time fraction and frequency of occurrence. Clusters are identified applying a criterion for the time average value of the volumetric solid fraction. A qualitative analysis of the influence of different drag function correlations on the hydrodynamics of the flow, including the evolution of coherent structures, is performed. The simulation predictions are also compared to experimental results. The results indicate that the choice of a correlation for drag function should be quite judicious. Finally it is shown that the mean clustering criteria of Sharma et al. should be modified to take into account other factors that influence cluster dynamics.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License