CFD Flow and Heat Transfer in Nonregular Packings for Fixed Bed Equipment Design

This work aims to test the application of computational fluid dynamics (CFD) modeling to fixed bed equipment design. Studies of CFD with a fixed bed design commonly use a regular packing approach to define bed geometry. However, assuming nonregular packing is a more realistic way to simulate the behavior of a fixed bed and therefore to estimate important design parameters. As a fluid flow simulation tool, CFD allows us to obtain a more accurate view of the fluid flow and heat transfer mechanisms present in fixed bed equipment. Forty-four spheres stacked in a nonregular maximum-space-occupying arrangement in a cylindrical container were used as the geometrical model. Estimates of the pressure drop along the bed, and wall heat transfer parameters were chosen as validation parameters. ΔP, Nuw, and kr/kf are given for different values of Re (transition and turbulent flow), and they are compared to commonly used correlations. Air was chosen as the flowing fluid. Cases of laminar and turbulent flows are presented, and their results are compared. To account for the fluid flow and thermally fluctuating components in the turbulent cases, one- and two-equation turbulence models were used for simulation.