A Bubbling Fluidization Model Using Kinetic Theory of Granular Flow Detailed knowledge of solids circulation bubble motion and frequen- cies of porosity oscillations is needed for a better understanding of tube erosion in fluidized bed combustors A predictive two-phase flow model A bubble-based drag model at the local-grid level is proposed to simulate gas-solid flows in bubbling fluidized beds of Geldart A particles In this model five balance equations are derived from the mass and the momentum conservation This set of equations along with necessary correlations for bubble diameter and voidage of emulsion phase is solved to obtain seven local structural parameters

Effects of the Distributor and Baffle on the Hydrodynamic

May 29 2019Therefore in this present study the hydrodynamics of particle flows in a bubbling fluidized bed was studied by a 2-D transient two-fluid model using a commercial CFD package (ANSYS Fluent 18 2) Afterwards the effects of the gas distributor and baffles characteristics (shape and position) on the gas distribution in the bubbling fluidized bed

This paper reports on CFD simulations of freely bubbling gas fluidized beds using CFX-4 a commercial code developed by CFX Ltd (formerly AEA Technology) Two Eulerian-Eulerian modelling approaches the granular kinetic model and the particle-bed model (Gibilaro 2001) have been investigated

Industrial scale bubbling fluidized bed simulations were carried out within the Kinetic Theory of Granular Flows (KTGF) The KTGF was applied within two different modelling frameworks the traditional Two Fluid Model (TFM) and a new approachin the form of the Dense Discrete Phase Model (DDPM) in order to identify any differences in performance

Comparison of continuum models using the kinetic theory of granular flow with discrete particle models and experiments: extent of particle mixing induced by bubbles / Bokkers G A van Sint Annaland M Kuipers J A M Proceedings of Fluidization XI Naples 2004 p

For a pseudofluid consisting of a particle assembly particle stress is transmitted through mutual contact between particles When the particles are densely agglomerated contacts are usually of long duration and frictional and this part of the stress is the frictional stress When the particles are sparsely spaced on the other hand contacts are temporary and collisional and this part of

A second

A gas–solid two-fluid model with the second-order moment method is presented to close the set of equations applied to fluidization With the kinetic theory of granular flow transport equations for the velocity moments are derived for the particle phase Closure equations for the third-order moments of velocity and for the fluid–particle velocity correlation are presented []

This paper describes the numerical study on the effect of inlet air distribution in the Bubbling Fluidized Bed (BFB) riser of diameter 0 18 m and 1 44 m of length using a 3-hole orifice plate A 2D model has been developed and meshed using Gambit software version 2 4 6 and was simulated using CFD code fluent version 6 3 Laminar model has been used for the modeling and Eulerian-Eulerian

Oct 31 2005The model is the standard kinetic theory CFD model (Gidaspow 1994) with the drag modified as suggested by Yang et al (2004) using the energy minimization multiscale approach A turbulent fluidized bed is characterized by two different coexisting regions: a bottom dense bubbling region and a dilute dispersed flow region (Berruti et al 1995)

Dec 01 2005The hydrodynamics and reaction kinetics of gas−solid fluidized beds containing fluid catalytic cracking (FCC) particles were simulated using computational fluid dynamics (CFD) Drag models of Gidaspow and Syamlal and O'Brien overestimated the drag force for the FCC particles and predicted a greater bed expansion in comparison to the experimental data The modified

It was found that lift force along with particle-wall collision and specularity coefficient play significant role in the simulation of horizontal gas-solid flows Granular temperature model by Ding and Gidaspow (1990 Ding J and D Gidaspow 1990 A bubbling fluidization model using kinetic theory of granular flow

By incorporating the kinetic theory of granular flow kinetic-frictional constitutive correlation and turbulence model a two-fluid model (TFM) was established to study the flow dynamics of core shooting process and reasonable agreement was obtained between simulations and experiments

A statistical model for the continuum description of particle motion and collisions in anisotropic turbulent shear flows is presented The model is based on a kinetic equation for the particle velocity probability density function The results are compared with the direct numerical simulation (DNS) data for a shear layer and a plane channel

A proper choice of the empirical drag model as well as of the drag correlation is therefore important This paper reports on CFD simulations of gas fluidized beds using a commercial code developed by AEA Technology CFX-4 Eulerian-Eulerian models such as the granular kinetic models (Gidaspow 1994) and the particle-bed model (Gibilaro

Clustering instabilities in sedimenting fluid–solid

Clustering instabilities in sedimenting fluid–solid systems: critical assessment of kinetic-theory-based predictions using direct numerical simulation data - Volume 823 - William D Fullmer Guodong Liu Xiaolong Yin Christine M Hrenya

(Chapter Headings): Transport Equations One-Dimensional Steady Gas Solid Flow Drift Flux Critical Granular Flow The Fluidized State On the Origin of Bubbles Inviscid Multiphase Flows: Bubbling Beds Viscous Flow and Circulating Fluidized Beds Kinetic Theory Approach Applications of Kinetic Theory Kinetic Theory of Granular Mixtures

Test cases of single rising bubble and a bubbling fluidized bed operated with a jet without a chemical reaction were studied in order to obtain fundamental insights in the prevailing mass transfer phenomena Numerical simulations were carried out to predict the dispersion of tracer gas using a two-fluid model based on Kinetic Theory of Granular

The paper presents a 2-D CFD model of liquid fuel combustion in bubbling fluid-ized bed The numerical procedure is based on the two-fluid Euler-Euler ap-proach where the velocity field of the gas and particles are modeled in analogy to the kinetic gas theory The model is

article{osti_1417968 title = {Kinetic theory-based numerical modeling and analysis of bi-disperse segregated mixture fluidized bed} author = {Konan N A and Huckaby E D } abstractNote = {We discuss a series of continuum Euler-Euler simulations of an initially mixed bi-disperse fluidized bed which segregates under certain operating conditions

Industrial scale bubbling fluidized bed simulations were carried out within the Kinetic Theory of Granular Flows (KTGF) The KTGF was applied within two different modelling frameworks the traditional Two Fluid Model (TFM) and a new approachin the form of the Dense Discrete Phase Model (DDPM) in order to identify any differences in performance

A bubbling fluidization model using kinetic theory of rough shperes Hydrodynamics of gas–solid bubbling fluidized beds are numerically simulated on the basis of the kinetic theory for flow of rough spheres Computed profiles of particles are in agreement with the experimental measurements in a bubbling fluidized bed