Pressure Drop Analysis of Incompressible Laminar Flow in a Low Aspect-Ratio Packed Bed Using CFD Simulations

Abstract

Computational Fluid Dynamics (CFD) is a worthwhile method for studying complex flows in packed bed reactors. The paper debates different CFD modeling approaches of incompressible laminar flow through packed beds with a particle to column diameter ratio of 2. Using COMSOL Multiphysics 5.6, five different cases have been simulated and compared in term of pressure drop. Excellent agreement was found between the proposed hypothetical and the resolved-particle (3D) models, mainly for the lower Inlet particle Reynolds numbers, with relative deviation of 3% and 7% at inlet Reynolds numbers of 27 and 55, respectively. Concerning the pseudo homogeneous cases, three different drag laws have been exercised and it has been found that applying the semi-empirical correlation, which takes into account the wall effects, in the flow equations showed the best agreement to the 3D model, with relative deviation being in the range 5%-25%. Considering these, one can recommend to use the proposed less computationally intensive approach or to apply the chosen drag law model in the momentum balance when designing a packed bed with aspect ratio of 2.