Radial distribution of solid holdup and its fluctuation characteristics in a three-phase scrubbing-cooling chamber

The local solid holdup in the three-phase scrubbing-cooling chamber was measured using optical fiber probes under different solid-phase properties, liquid-phase properties, and superficial gas velocities. The root-mean-square (RMS) fluctuations of the solid fraction ((v) over bar') were used to describe the local solid volume fraction fluctuations quantitatively. The results showed that the bubble wake is the dominant factor affecting the radial solid holdup distribution uniformity. The bubble wake entrainment in the central area and the fluid reflux in the near-wall area resulted in the radial distribution of solids holdup with ``low center and high sidewalls." In addition, the increase of solid volume fraction and the enhanced entrainment ability of bubble wake both encourage the growth of local (v) over bar' and lead to a more uneven radial distribution of (v) over bar'. A regional model of (v) over bar' is established, and its predicted values agree well with the experimental values. (C) 2021 Elsevier Ltd. All rights reserved.