Computational studies on flow maldistribution of Newtonian liquids in periodic packed beds

Abstract

Abstract Packed bed, one of the most important reactors in several chemical processes and petroleum refinery operations, has been a field of interest for many researchers. Familiarized with the steady state hydrodynamics over the past two decades, researchers are now engaged in exploring the efficacy of unsteady state operation of packed bed reactors (PBRs) to extract even more from its efficiency and performance (Atta et al., 2014). The present work deals with CFD studies on cyclic modes of single phase flow operation in structured packed beds having face centered cubic (FCC) and modified simple cubic (SC) packing arrangements which are modeled by unit cell approach. Max-min and on-off flow operations at three different particle Reynolds number ( Re p ) are carried out for five different splits. Liquid distribution is quantitatively examined at the mid-plane of both geometries by evaluating mass fluxes. The mass flux analysis reveals that in either case of on-off and max-min operation, liquid distribution is found to improve than for continuous flow. A distribution coefficient, calculated using the standard deviation concept, indicates that the FCC packing shows the best distribution for max-min operation with the split having maximum peak flow duration. However, exactly opposite trend is observed in modified SC, where the split with lowest peak flow rate duration shows the best distribution among the five splits. This work using a single phase is not only relevant to various practical application but also sets the foundation in exploring multiphase flow hydrodynamics of cyclic packed beds.