(501a) A Numerical Model for the Motion of Large Non-Spherical Solid in Fluidized Bed

In a number of practical applications of fluidized bed such as coal/wooden biomass gasification and combustion, the size and shape of solid materials are not uniform and large non-spherical solids are coexisting with small emulsion solids in the bed to enhance fluidization and heat transfer. The size of these solids is largely different; fuel solids are more than ten times larger comparing to emulsion particles. Fuel solids, especially pellets, are far from spherical and the non-sphericity is expected to play an important role for contact and hydrodynamic interactions. It is difficult to treat these systems by the existing numerical models. Tsuji et al. (2014) proposed a numerical model which expresses the behavior of flows including dense solids with large size difference based on the DEM-CFD coupling method. In their model, the interaction force between fluid and large solid is estimated by assuming a large solid is consisted of dense small fictitious particles. Their study was limited to spherical solids. In the present study, on the other hand, non-sphericity of large objects is taken into account by introducing Multi-sphere model. The model was applied to the motion of a single large non-spherical object in a bubbling fluidized bed and validation study was performed through the comparison with corresponding experiment. We observed similar behaviors of the large object between calculation and experiment.