Critical comparison of hydrodynamic models for gas-solid fluidized beds - Part II: freely bubbling gas-solid fluidized beds

Correct prediction of spontaneous bubble formation in freely bubbling gas¿solid fluidized beds using Eulerian models, strongly depends on the description of the internal momentum transfer in the particulate phase. In this part, the comparison of the simple classical model, describing the solid phase pressure only as a function of a solid porosity by an empirical correlation and assuming the solid phase viscosity constant, which is referred to as the constant viscosity model (CVM), with the more fundamental model based on the kinetic theory of granular flow (KTGF), in which the solid phase properties are described in much more detail in terms of instantaneous binary particle¿particle interactions, has been extended for freely bubbling fluidized beds. The performance of the KTGF and the CVM in predicting the hydrodynamics of freely bubbling fluidized beds has been compared with experimental data and correlations taken from the literature.