Euler-Lagrange model of particles circulation in a spout-fluid bed apparatus for dry coating

Abstract

The main objective of the study was to develop a model describing the flow of particles (cores) in an apparatus operating within the range of the fast circulating dilute spout-fluid bed. The greatest emphasis was placed on the selection of appropriate description of the particle-wall interactions (impact model or fixed values of restitution coefficients). Its influence on the dispersed phase velocity in the draft tube and annulus of the apparatus was investigated. Results obtained from computer simulations were compared with our own experimental data. The use of equations calculating normal and tangential restitution coefficient resulted in a noticeable improvement in the accuracy of results only in the area of the draft tube in relation to the fixed restitution coefficient approach. It was found that the flow hydrodynamics and apparatus geometry favour computing of low restitution coefficients in the annular zone.