Origin of regime transition to turbulent flow in bubble column: Orifice- and column-induced transitions

Comprehensive experimental investigation of counter-current bubble column hydrodynamics: Holdup, flow regime transition, bubble size distributions and local flow properties

“…4b). Indeed, at the sparger, some bubbles were characterized by an ellipsoidal shape, and others by an irregular shape (i.e., due to the channeling effect (Hur et al, 2013)). …”

“…Focusing on the batch mode, the typical values of U trans found in the literature for air-water systems in bubble columns of diameter greater than 0.15 m range between 0.01 and 0.08 m/s under ambient operating conditions (Dargar and Macchi, 2006;Hur et al, 2013;Krishna et al, 1991;Letzel et al, 1999;Reilly et al, 1994;Ruzicka et al, 2001;Schumpe and Grund, 1986;Urseanu, 2000;Wilkinson et al, 1992;Zahradnik et al, 1997). The value depends mainly on the sparger type.…”

“…30b). It is worth noting that the BSD at the sparger depends on many design parameters (i.e., the hole of the sparger and the flowrate) as reported by Hur et al (2013) and Geary and Rice (1991). For example, a sensitivity analysis made by Cao et al (2009) using the Geary and Rice (1991) model showed that increasing hole flowrate or decreasing hole dimensions lead to larger bubbles, whereas an increasing number of holes results in smaller bubbles detaching from the sparger.…”

“…Image analysis has been mostly applied to rectangular/small-scale (Lau et al, 2013a(Lau et al, , 2013bZaruba et al, 2005) or medium scale (Schäfer et al, 2002) bubble columns, but there is a lack of studies concerning BSDs in largediameter bubble columns. Furthermore, studies analyzing the bubble size distributions near the sparger are uncommon (Hur et al, 2013), and the influence of the liquid velocity on the bubble shape and bubble size distribution is far from being understood (Besagni and Inzoli, 2016b). In the present study, we have applied a method based on human recognition of the bubble edge Besagni and Inzoli, 2016b).…”

Annular Gap Bubble Column: Experimental Investigation and Computational Fluid Dynamics Modeling

“…Typical values of U trans found in the literature for the air-water systems in bubble columns with diameters higher than 0.15 m range between 0.01 and 0.08 m/s at ambient operating conditions [24,[57][58][59][60][61][62][63][64][65][66]. The value depends mainly on the distributor type.…”