| Computational Fluid Dynamics (CFD) has proven to be a powerful tool to numerically solve the fluid-flow equations so it gives a further insight into the flow pattern of contacting equipment. There has been a fast growing in the study of applications in fluid flow and heat transfer, and several authors have used it to analyze flow patterns in fixed-bed equipment and to predict heat transfer parameters in studied cases. Particle-to-fluid heat transfer is studied in a maximum-occupying-space arrangement of solid spheres in a cylindrical container, in order to simulate via CFD the heat transfer behavior in a supercritical catalytic reactor under steady state conditions. Supercritical CO2 was chosen as circulating fluid; buoyancy terms were found to be relevant in calculations through a dimensionless analysis done to Navier-Stokes equations, and therefore are used during simulations. C-written programmed modules based on the SRK equation of state and accepted correlations for high pressure properties estimation have been implemented for use with CFD commercial codes in order to estimate the transport properties of the fluid (i.e., density, viscosity, heat capacity and thermal conductivity).
An understanding of the particle-to-fluid heat transfer phenomena in a porous media implies the study of the fluid transport model within the void space; this fact is of fundamental importance to many chemical engineering systems such as fixed bed extraction or catalytic reaction equipment. Experimental and theoretical studies of flow through such systems often treat the porous medium as an effectively homogeneous system and concentrate on the bulk properties of the flow. Such an approach neglects completely the complexities of the flow within the void space of the porous medium, reducing the description of the problem to macroscopic average or effective quantities. The details of this local flow process may, however, be the most important factor influencing the behavior of a given physical process occurring within the system, and are crucial to understanding the detailed mechanisms of, for example, heat and mass dispersion and interface transport.
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