Preface

A novel methodology for simulating vibrated fluidized beds using two-fluid models

“…(9) and (10) Regarding the granular temperature H, it accounts for the qua dratic difference between the individual velocity of particles and the bulk velocity v p of the particle phase [26]. By definition this velocity difference is stochastic, which implies that changing from a static to a moving system of reference modifies the bulk velocity as well as the individual velocity of particles, but does not alter the difference between individual and bulk velocities.…”

“…The description of gas fluidized beds as two interpenetrating continua is the essence of two fluid models [22,26]. One contin uum refers to the gas phase in the bed and the other to the particle phase (also known as particulate or solids phase).…”

“…In the momentum equation, the particle phase is treated as a fluid with effective transport properties [26]. Commonly, the conservation equations of mass and momen tum are solved together with the differential equation for the transport of granular temperature H, also included in Table 1, which is based on the kinetic theory of granular flows and provides the level of random fluctuation of particle velocity due to collisions [26]. The granular temperature is required for the closure expres sions of the drag coefficient K gp , the solid viscosities l p and k p , and the effective particle pressure p p .…”

“…Thus, a different computa tional strategy would be desirable to numerically simulate larger beds while achieving computing times similar to the ones required for the simulation of conventional FB. In this regard, simulation of small and medium scale conventional gas fluidized beds is com monly undertaken by means of two fluid computational fluid dynamic (CFD) models, also known as Eulerian Eulerian two fluid models, which are primarily based on the representation of the gas phase and the particulate phase as two interpenetrating con tinua [22,26]. Two fluid models provide information about the macroscopic hydrodynamics (i.e.…”

Numerical investigation of solid mixing in a fluidized bed coating process

“…Since this study intends to examine the gas solid dynamics of the bed globally, the EEM model was adopted. The kinetic theory model for multiphase granular flow as described by Gidaspow [5] was used to calculate the solid phase pressure as well as the bulk and shear viscosities. The values used in this model are: a maximum solid fraction of 0.62, a value of 0.9 for the resitution coefficient and an internal friction angle of 30° for the frictional stress mode.…”