Cluster structure-dependent drag model for liquid–solid circulating fluidized bed

Abstract

The formation of clusters in liquid–solid circulating fluidized beds effects on momentum transfer between phases. In this article, a cluster structure-dependent drag model is proposed to take the effect of clusters on momentum transfer between dispersed phase and clusters into account by means of an Eulerian–Eulerian two-fluid model. The momentum and energy balances that characterize the clusters in the dense phase as well as dispersed particles in the dilute phase are described by the multi-scale resolution approach. The proposed model of cluster structure-dependent (CSD) drag coefficient is on the basis of the minimization of energy dissipation by heterogeneous drag (MEDHD) as a function of Reynolds number. The CSD drag coefficient model is incorporated into the two-fluid model to simulate flow behavior of liquid and particles in a liquid–solid riser. Predicted volume fraction and particle velocity distributions are in good agreement with experimental data published in the literature.