Modification of kinetic theory of granular flow for frictional spheres, part II: Model validation

Abstract

The hydrodynamics of a dense solid–gas fluidized bed is studied, using a two fluid model (TFM) based on our newly developed kinetic theory of granular flow (KTGF) for rotating rough particles. The TFM simulations are validated by comparing with PIV-DIA experimental data (Buist et al., 2014) and results obtained from discrete particle model (DPM) simulations of the bubbling fluidized bed. The TFM model predictions agree well with the experimental results for the time-averaged particle axial velocity and solids volume fraction. The predicted levels of the translational granular temperatures and solids circulation patterns compare reasonably well with the results obtained from the DPM simulations. The predicted rotational granular temperature in our TFM simulations shows an almost uniform distribution in the bed as a result of the assumptions that both the local mean rotational velocity and the gradient of the rotational granular temperature at the wall are zero, indicating directions for future improvement. A comparison between TFM simulations using the present KTGF model, and a more simple kinetic theory for rapid flow of slightly frictional, nearly elastic spheres derived by Jenkins and Zhang (2002), is carried out to investigate the influence of particle friction in the fluidized bed. The present KTGF model leads to better agreement with DPM simulations and experimental results for the axial particle velocity profiles and solids volume fraction distribution.