Study of Flow of Fine Particles with an Agglomerate-Based Approach

Flow behavior of fine particle agglomerations in CFB was numerically studied by means of a two-fluid flow model considering dynamics of collision between fine particles. The model of particle viscosity and pressure of particle agglomerations were proposed, and the size of agglomerations was estimated by model proposed by Zhou et al (1999) from force balance acting on an agglomerations. The results of simulation showed that the flow behavior of fine particle agglomerations was the annulus-dense core flow structure of "S" type. The big particle agglomerations mainly appeared in the bottom of riser and walls. While the small particle agglomerations appeared in dilute regime of center of riser. The predicted agglomerates distributions are in agreement with experimental data of Li et al (1999) in a circulating fluidized bed riser. The influences of restitution coefficient on the distributions of velocity and concentration of agglomerates were analyzed.