Experimental studies on bubble aspect ratio and corresponding correlations under bubble swarm condition

A study of bubble size/shape evolution in microbubble countercurrent contacting flotation column

“…Figure 11 shows the predicted values of Equations () and () for each set of aspect ratio data. It can be seen from the figure that the two equations had good predictions for aspect ratio data of Liu et al, 12 Besagni and Inzoli., 24 Ziegenhein and Lucas, 33 and Ziegenhein et al, 34 which were in line with the current 20% error range. By adding GE609 to change the air–liquid surface properties, Work 2–5 recorded the bubble aspect ratios at 0, 0.0118, 0.0353, 0.0471, and 0.0588 mol/m 3 , respectively.…”

“…Regarding the dimensionless array, Liu et al 12,18 believed that the EoRe dimensionless array could consider all the characteristic forces and had high accuracy when the liquid phase properties changed. By analyzing the equation of the multiple linear regression, Besagni and Inzoli 24 concluded that the WeMo combination had the best fitting effect on experimental data.…”

“…However, Loth 23 raised the question about extending the experimental results obtained by a single bubble to two‐phase or multiphase flow under other flow conditions because the liquid flow conditions, phase characteristics, and inter‐bubble interactions will inevitably affect the shapes of the bubbles. Liu et al 12 found that the aspect ratios of the bubble tend to be stable with the increase of bubble diameter, instead of the inverse proportion of the bubble diameters predicted by the correlation equation obtained in the single bubble test. Besagni and Inzoli 24 discussed the necessary connection between the bubble shape in group bubbles and the specific operating conditions.…”

Prediction of Bubble Size Distribution above the Bubble-Breaking Plate

“…Therefore, predicting the bubble shape factor enhances the accuracy of the BSD derivation. Numerous correlations have been developed to relate the shape factor as a quantitative representation of the bubble to different dimensionless numbers, and the more applied dimensionless numbers mainly include the Eötvös number ( E o = normalΔ ρ g d normalB , normalv normalo normall σ l ), Morton number ( M o = g μ l 4 normalΔ ρ ρ l 2 σ l 3 ), Reynolds number ( R e = d normalB , normalv normalo normall u t ρ l μ l ), Weber number ( W e = ρ l u t 2 d normalB , normalv normalo normall σ l ), etc. Bozzano and Dente represented the bubble by superpositioning two flat hemispheres with a common semi-long axis.…”

“…Therefore, predicting the bubble shape factor enhances the accuracy of the BSD derivation. Numerous correlations have been developed to relate the shape factor as a quantitative representation of the bubble to different dimensionless numbers, and the more applied dimensionless numbers mainly include 39 the Eoẗvos number (Eo The gas distributor significantly affects the hydrodynamic behavior of the gas−liquid two-phase flow. 41,42 The bubble column can be divided into "distributor region" and "main region" along the height: 43 the strong turbulence in the region near the distributor leads to the decrease of bubble coalescence degree, and the bubble size depends on the turbulence degree of the liquid phase and the bubble coalescence property; the bubble size in the main body region is balanced, almost unaffected by the distributor design.…”