CFD investigation of the hydrodynamic behaviour of inverse fluidized bed using non‐Newtonian fluids

Abstract The solid–liquid fluidization system has garnered significant scientific and industrial attention in recent years due to its broad applicability in process engineering. Contemporary global initiatives for the treatment of industrial effluents and wastewater have motivated researchers to explore inverse fluidization as a promising alternative to conventional fluidization techniques. This preference arises from its inherent advantages, including operational simplicity, ease of handling, lower process cost, reduced energy consumption, and enhanced overall efficiency. The present study focuses on the determination of the minimum inverse fluidization velocity using four different polymeric particles, such as low density polyethylene grade 1 (LDPE1), low density polyethylene grade 2 (LDPE2), high density polyethylene (HDPE), and polypropylene (PP), respectively, which are dispersed in a non‐Newtonian dilute solution of sodium salt of carboxymethyl cellulose at four varying concentrations. Empirical correlations have been developed to predict the minimum inverse fluidization velocity as a function of relevant physical and dynamic parameters of the system. A Euler–Euler multiphase model has been employed to discretize the system, solving two sets of Navier–Stokes equations, corresponding continuity equations, and a transport equation. The effects of variations in the concentration of the continuous phase, the initial mass of the dispersed phase, and the particle type on the volume fraction and velocity distribution have been systematically examined. The simulation results provide comprehensive insights into the hydrodynamic behaviour of the inverse fluidization process, offering a deeper understanding of system dynamics and performance characteristics.