Effects of fine particles on terminal velocities of single bubbles in a narrow channel between parallel flat plates. (June 2020)

• Record Type: Journal Article
• Authors: Hashida, Masaaki; Hayashi, Kosuke; Tomiyama, Akio
• Is Part Of: International journal of multiphase flow. Volume 127(2020)
• Publication Date: 2020-06
• Subjects: Planar bubble -- Slurry -- Apparent viscosity -- Bubble lateral motion; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2020.103270
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: Shapes and velocities of bubbles in slurry in a narrow channel are measured. Fine particle effect on bubble velocity is expressed with apparent viscosity. Bubbles in slurry show the same characteristics as those in viscous liquids. Abstract: Effects of the presence of solid particles on the terminal velocities, VB, of single bubbles in a narrow channel were investigated. The gap thickness of the narrow channel was 3 mm. The bubble diameter, dB, was varied from 7 to 20 mm. Air, purified water and fine silica particles of 4.1 μm diameter were used for the gas, liquid and solid phases, respectively. The volume concentration of the particles, CS, was from 0.20 to 0.40. The apparent slurry viscosity, μ SL, ranged from 1.7 to 3.1 mPa⋅s. The applicability of a velocity correlation proposed for bubbles in gas-liquid systems to bubbles in slurry was examined. The following conclusions were obtained under the present experimental conditions: (1) the dependence of VB on dB in slurry is similar to that in glycerol-water solutions, and the bubble Reynolds number in slurry and a glycerol-water solution of the same Morton number are almost the same for CS ≤ 0.35, and (2) the velocity correlation for gas-liquid systems is applicable to slurry with fine particles for CS ≤ 0.35 by using μ SL instead of the liquid viscosity in the correlation.