CFD Simulation of Flow Behavior and Apparent Viscosity Distribution of Polymer Solution in a Rotating Packed Bed.

Abstract

High-gravity rotating packed beds enhance mass transfer via high-gravity fields, where the flow and viscosity distribution of polymer solutions govern dissolution efficiency and equipment compactness. Understanding these behaviors is essential for optimizing polymer dissolution in offshore polymer flooding, yet experimental methods are hindered by poor light transmittance and observational blind spots, making it difficult to capture the dynamic dispersion and evolution of polymer solutions within the wire mesh packing. To address this issue, a two-dimensional computational model was constructed by combining the VOF multiphase model with the Carreau-Yassuda viscosity model, accounting for the shear-thinning characteristics and viscosity variations of the polymer solution. The effects of zero-shear viscosity, rotational speed, and inlet velocity on flow morphology, aggregation, and apparent viscosity distribution were systematically examined. Results show the following: (1) Increasing rotational speed from 300 to 900 rpm promotes the transition from film-dominated to droplet-dominated flow, increasing zero-shear viscosity from 59 to 348 mPa·s suppresses dispersion and forms coexisting films and droplets, and increasing inlet velocity from 1.74 to 3.17 m/s drives the transition from droplet-dominated to film-dominated flow. (2) Increasing rotational speed reduces apparent viscosity by up to 30% and improves distribution uniformity, with a turning point near 1000 rpm; inlet velocity has limited effects, with radial distribution higher in the inner region. (3) The Carreau-Yassuda model reveals a shear-thinning effect, where high rotational speed mitigates the influence of high zero-shear viscosity, and the combination of high rotational speed and high inlet velocity synergistically enhances dispersion. These findings provide a theoretical basis for optimizing polymer dissolution in high-gravity carbon capture processes.