Numerical Study on Porosity Distribution and Hydrodynamics of Packed Bed in Narrow Square Channels
Recently square-channel packed bed reactors with micro to milli dimensions are often found in the literature on process intensification. However, its porosity profiles and resultant flow behaviors have been overlooked. Therefore, this study proposes two new CFD approaches to model such reactors relying on the accurate local porosity profiles in the square bed. Discrete element method was employed to model random packed beds of monodisperse spherical particles in square channels with channel-to-particle size ratio of 3 to 10. The obtained lateral porosity profiles were axially averaged and expressed as a function of distance from the wall in three defined zones. Momentum source term to be added in the momentum conservation equation was calculated based on the local porosity profile functions in Correlations-based Continuum (CC) approach, while on the axially-averaged porosity profiles in Pseudo-Particle Resolved (PPR) approach. The square beds’ hydrodynamic behaviors were investigated using CC and PPR approaches, which were validated with Particle Resolved approach in terms of velocity profile, and with empirical correlations for pressure drop.
Keywords: packed bed, square channel,porosity distribution,flow channeling