Hydrodynamics of particle segregation in fluidized beds

Effects of limestone calcination on the gasification processes in a BFB coal gasifier

“…The model assumes the gas and solid phases as continuous and fully interpenetrating within each control volume. It is less computationally exhaustive in comparison to the discrete Eulerian-Lagrangian method which simulates the individual particle dynamics (Gera et al, 1998(Gera et al, , 2004Ibsen et al, 2004) and the complete Lagrangian model which models both particles and fluid with a Lagrangian approach (Ge and Li, 1997. A combination of the Eulerian-Eulerian model and the Eulerian-Lagrangian model was recently considered by Papadikis et al (2008Papadikis et al ( , 2009aPapadikis et al ( ,b,c,d, 2010a where one or two Lagrangian biomass particles were introduced to a Eulerian-Eulerian bubbling bed of inert sand.…”

Mutiscale Modeling of Segregation in Granular Flows

“…The particle rotation model predicted larger fluctuations of the segregation percentages, which can also be attributed to the increased bubble intensity by this model. The major discrepancy between numerical results and experimental results, however, is due to the fact that the large particles are not very well fluidized in this conditions and thus the "hindrance effect" (Gera et al, 2004) is produced between the small particles and the rehctant large particles. To account for this kind of hindrance effect is beyond the capability of the current kinetic theory for granular flows.…”

“…For example, in a gas fluidized bed of a binary mixture, the large particles may not be well fluidized when the gas velocity is between the two minimum fluidization velocities for the two different types of particles. The closely packed particles may hinder the segregation of smaller particles (Gera et al, 2004). Many practical flow situations, especially those strongly affected by gravitational forces, fall into a transitiond regime (Savage, 1998).…”

Validation of results from Barracuda CFD modelling to predict the minimum fluidization velocity and the pressure drop of Geldart A particles

“…This makes the MP-PIC method more computationally efficient than the more commonly used discrete element method (DEM) (Tsuji et al, 1993, Goldschmidt et al, 2004, Gera et al, 2004, hence it can be applied to larger systems. The CPFD method models the fluid as a continuum and the computational particles as discrete particles exposed to three-dimensional forces as fluid drag, gravity, static-dynamic friction, particle collision and possibly other forces (Dale M. Snider, 2007).…”