Abstract
Simulations of fluidized beds are performed to study and determine the effect on the use of coordinate systems and geometrical configurations
to model fluidized bed reactors. Computational fluid dynamics is employed for an Eulerian-Eulerian model, which represents each phase as an
interspersed continuum. The transport equation for granular temperature is solved and a hyperbolic tangent function is used to provide a smooth
transition between the plastic and viscous regimes for the solid phase. The aim of the present work is to show the range of validity for employing
simulations based on a 2D Cartesian coordinate system to approximate both cylindrical and rectangular fluidized beds. Three different fluidization
regimes, bubbling, slugging and turbulent regimes, are investigated and the results of 2D and 3D simulations are presented for both cylindrical and
rectangular domains. The results demonstrate that a 2D Cartesian system can be used to successfully simulate and predict a bubbling regime.
However, caution must be exercised when using 2D Cartesian coordinates for other fluidized regimes. A budget analysis that explains all the
differences in detail is presented in Part II [N. Xie, F. Battaglia, S. Pannala, Effects of Using Two-Versus Three-Dimensional Computational
Modeling of Fluidized Beds: Part II, budget analysis, 182 (1) (2007) 14] to complement the hydrodynamic theory of this paper.