This paper presents a computational study of the flow behavior in a cold-flow pilot-scale circulating fluidized bed. A multi-fluid Ž . Computational Fluid Dynamics CFD model has been developed and verified against experimental data reported in the literature. The flow model is based on an Eulerian description of the phases where the kinetic theory of granular flow forms the basis for the turbul...

How to accurately probe chemically reactive flows with essential thermodynamic nonequilibrium effects is an open issue. Via the Chapman-Enskog analysis, local particle velocity distribution function derived from gas kinetic theory. It demonstrated theoretically and numerically that depends on physical quantities derivatives, independent of chemical reactions directly. Based simulation results d...

Mesoscopic structures form in dense granular materials due to the self-organisation of the constituent particles. These structures have internal structural degrees of freedom in addition to the translational degree of freedom. The resultant granular elasticity, which exhibits intrinsic variations and inevitable relaxation, is a key quantity that accounts for macroscopic solid- or fluid-like pro...

There have been many attempts to derive continuum models for dense granular flow, but a general theory is still lacking. Here, we start with Mohr-Coulomb plasticity for quasi-two-dimensional granular materials to calculate (average) stresses and slip planes, but we propose a "stochastic flow rule" (SFR) to replace the principle of coaxiality in classical plasticity. The SFR takes into account t...

We find in complementary experiments and event driven simulations of sheared inelastic hard spheres that the velocity autocorrelation function ψ(t) decays much faster than t obtained for a fluid of elastic spheres at equilibrium. Particle displacements are measured in experiments inside a gravity driven flow sheared by a rough wall. The average packing fraction obtained in the experiments is 0....

To model cohesionless granular flow using continuum theory, the usual approach is to assume the cohesionless Coulomb-Mohr yield condition. However, this yield condition assumes that the angle of internal friction is constant, when according to experimental evidence for most powders the angle of internal friction is not constant along the yield locus, but decreases for decreasing normal stress c...

Gas-particle flows can be described by a kinetic equation for the particle phase coupled with the Navier−Stokes equations for the fluid phase through a momentum exchange term. The direct solution of the kinetic equation is prohibitive for most applications due to the high dimensionality of the space of independent variables. A viable alternative is represented by moment methods, where moments o...

Nitrate contamination of water resources and the growing concentration of nitrate endanger human health and the environment and considering its reduction strategies from water resources is important. The aim of this study was to investigate the possibility of removal of nitrate from aqueous solutions using granular activated carbon from grape wood coated with iron nanoparticles. The results sho...