Flow Pattern Transition and Liquid Element Characteristics in a Disk-Distributor Rotating Packed Bed: A Visual Study for Viscous Fluid

Rotating packed beds (RPBs) possess great potential in applications to high-viscosity processes, whereas the corresponding fundamental research lags behind, particularly in flow characteristics. In this work, a visual study of viscous liquid flow (11-59372 mPa.s) was implemented in a disk-distributor RPB (DRPB) using high-speed photography technology. Typical flow patterns in packing involving droplet, short ligament, continuous ligament, and film flows were observed. Analyses of flow pattern transition confirmed that droplet flow was scarcely formed at moderate and high viscosities, which disappeared for viscosity larger than 143 mPa.s. A semiempirical model was constructed to quantify liquid element characteristics. Equivalent spreading radius (R-F) and average thickness ((h) over bar (F)) of liquid film were in ranges of 82.5177.56 mm and 0.31-5.61 mm, while total number (N-L) and average diameter ((d) over bar (L)) of liquid ligament were in ranges of 181-12553 and 0.25-3.22 mm, respectively. The deviation between experimental and model-predicted d(L) was within +/- 20%, demonstrating the reasonability of the semiempirical model. In addition, dimensionless correlations of (h) over bar (F) and (d) over bar (L) were established. (C) 2022 Elsevier Ltd. All rights reserved.