COMPUTER-SIMULATION OF THE HYDRODYNAMICS OF A 2-DIMENSIONAL GAS-FLUIDIZED BED

A first principles model of a gas-fluidized bed has been applied to ca lculate the hydrodynamics of a two-dimensional (2-D) bed with an orifi ce in the middle of a porous plate distributor. The advanced hydrodyna mic model is based on a two fluid model approach in which both phases are considered to be continuous and fully interpenetrating. Conservati on equations for mass, momentum and thermal energy have been solved nu merically by a finite difference technique on a mini-computer. Our com puter model calculates the porosity, the pressure, the fluidum phase t emperature, the solid phase temperature and the velocity fields of bot h phases in 2-D Cartesian or axisymmetrical cylindrical coordinates. T he new feature of the present model is the incorporation of Newtonian behaviour in the gas and solid phases. Our preliminary calculations in dicate that the sensitivity of the computed bubble size with respect t o the bed rheology (i.e. the solid phase viscosity) is quite small. Ho wever the bubble shape appears to be much more sensitive to the bed rh eology. Results of the calculations have been compared with data obtai ned from an experimental cold-flow model (height: 1000 mm, width: 570 mm, depth: 15 mm).