scholarly journals Effect of solids on homogeneous–heterogeneous flow regime transition in bubble columns

2005 ◽  
Vol 60 (22) ◽  
pp. 6013-6026 ◽  
Author(s):  
P.C. Mena ◽  
M.C. Ruzicka ◽  
F.A. Rocha ◽  
J.A. Teixeira ◽  
J. Drahoš
Keyword(s):  
Flow Regime ◽  
Bubble Columns ◽  
Regime Transition ◽  
Heterogeneous Flow ◽  
Flow Regime Transition

scholarly journals Effect of viscosity on homogeneous–heterogeneous flow regime transition in bubble columns

2003 ◽  
Vol 96 (1-3) ◽  
pp. 15-22 ◽  
Author(s):  
M.C. Ruzicka ◽  
J. Drahoš ◽  
P.C. Mena ◽  
J.A. Teixeira
Keyword(s):  
Flow Regime ◽  
Bubble Columns ◽  
Regime Transition ◽  
Heterogeneous Flow ◽  
Flow Regime Transition

Flow regime transition identification in three phase co-current bubble columns

2012 ◽  
Vol 91 (3) ◽  
pp. 516-523 ◽  
Author(s):  
S. Kumar ◽  
N. Srinivasulu ◽  
P. Munshi ◽  
A. Khanna
Keyword(s):  
Flow Regime ◽  
Bubble Columns ◽  
Regime Transition ◽  
Flow Regime Transition ◽  
Three Phase

A Review on Flow Regime Transition in Bubble Columns

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Ashfaq Shaikh ◽  
Muthanna H. Al-Dahhan
Keyword(s):  
Flow Regime ◽  
Bubble Column ◽  
Flow Behavior ◽  
Scale Up ◽  
Experimental Studies ◽  
Flow Regimes ◽  
Bubble Columns ◽  
Linear Stability Theory ◽  
Regime Transition ◽  
Flow Regime Transition

Due to varied flow behavior, the demarcation of hydrodynamic flow regimes is an important task in the design and scale-up of bubble column reactors. This article reviews most hydrodynamic studies performed for flow regime identification in bubble columns. It begins with a brief introduction to various flow regimes. The second section examines experimental methods for measurement of flow regime transition. A few experimental studies are presented in detail, followed by the effect of operating and design conditions on flow regime transition. A table summarizes the reported experimental studies, along with their operating and design conditions and significant conclusions. The next section deals with the current state of transition prediction, and includes purely empirical correlations, semi-empirical models, linear stability theory, and Computational Fluid Dynamics (CFD) based studies.

scholarly journals Effect of Perforated Plate Open Area on Gas Holdup in Rayon Fiber Suspensions

2005 ◽  
Vol 127 (4) ◽  
pp. 816-823 ◽  
Author(s):  
Xuefeng Su ◽  
Theodore J. Heindel
Keyword(s):  
Flow Regime ◽  
Mass Fraction ◽  
Gas Holdup ◽  
Fiber Suspensions ◽  
Regime Transition ◽  
Open Area ◽  
Heterogeneous Flow ◽  
Flow Regime Transition ◽  
Mass Fractions ◽  
Rayon Fiber

Three different aeration plates are used to study their effect on gas holdup and flow regime transition in fiber suspensions. The aeration plates differ by their open-area ratios (A=0.57%, 0.99%, and 2.14%), where the hole diameter remains the same while the number of holes increase. Experiments are performed using three different Rayon fiber lengths (L=3, 6, and 12mm) over a range of superficial gas velocities (Ug⩽18cm∕s) and fiber mass fractions (0⩽C⩽1.8%) in a 15.24cm dia semi-batch bubble column. Experimental results show that the aeration plate with A=0.99% produces the highest gas holdup in an air-water system and low fiber mass fraction suspensions, and the plate with A=2.14% yields the lowest gas holdup in these systems. In medium fiber mass fraction suspensions, the plate with A=0.57% produces slightly higher gas holdup values, while the other two plates yield similar results. The effect of the aeration plate open area on gas holdup diminishes at high fiber mass fractions (C⩾1.2%). All aeration plates generate homogeneous, transitional, and heterogeneous flow regimes over the range of superficial gas velocities for air-water and low fiber mass fraction suspensions. However, the aeration plate with A=2.14% enhances the flow regime transition, i.e., the superficial gas velocity at which transitional flow appears is lower. Additionally, the fiber mass fraction at which pure heterogeneous flow is observed is lower when A=2.14%.

Gas holdup and hydrodynamic flow regime transition in bubble columns

2017 ◽  
Vol 56 ◽  
pp. 450-462 ◽  
Author(s):  
Jun Young Kim ◽  
Bongjun Kim ◽  
Nam-Sun Nho ◽  
Kang-Seok Go ◽  
Woohyun Kim ◽  
...  
Keyword(s):  
Flow Regime ◽  
Gas Holdup ◽  
Hydrodynamic Flow ◽  
Bubble Columns ◽  
Regime Transition ◽  
Flow Regime Transition

Flow regime transition in bubble columns

1999 ◽  
Vol 26 (4) ◽  
pp. 467-475 ◽  
Author(s):  
R. Krishna ◽  
J. Ellenberger ◽  
C. Maretto
Keyword(s):  
Flow Regime ◽  
Bubble Columns ◽  
Regime Transition ◽  
Flow Regime Transition

scholarly journals Effect of Gas Distributor on Gas Holdup in Fiber Suspensions

Volume 3 ◽  
2004 ◽  
Author(s):  
Xuefeng Su ◽  
Theodore J. Heindel
Keyword(s):  
Flow Regime ◽  
Mass Fraction ◽  
Gas Holdup ◽  
Transitional Flow ◽  
Orifice Diameter ◽  
Fiber Suspensions ◽  
Regime Transition ◽  
Heterogeneous Flow ◽  
Flow Regime Transition ◽  
Mass Fractions

Two different aeration plates are used to study their effect on gas holdup and flow regime transition in fiber suspensions. Two gas distributors with different open areas (A = 0.57% and 2.14%) and the same orifice diameter (do = 1 mm) are used, and experiments are performed using three different Rayon fiber lengths (L = 3, 6, and 12 mm) over a range of superficial gas velocities (Ug ≤ 18 cm/s) and a range of fiber mass fractions (0 ≤ C ≤ 1.8%) in a 15.24 cm diameter semi-batch bubble column. Experimental results show that the distributor with A = 2.14% tends to produce lower gas holdup than the one with A = 0.57% for both air-water systems and fiber slurries. However, the effect of distributor open area on gas holdup diminishes at high fiber mass fractions (C ≤ 1.2%). Both distributors generate homogeneous, transitional, and heterogeneous flow regimes over the range of superficial gas velocities for air-water and low fiber mass fraction suspensions. However, the distributor with A = 2.14% enhances the flow regime transition, i.e., the superficial gas velocity at which the transitional flow regime appears is lower. Additionally, the fiber mass fraction at which purely heterogeneous flow is observed is lower when A = 2.14%.

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