scholarly journals Interactions between gas–liquid mass transfer and bubble behaviours

2019 ◽  
Vol 6 (5) ◽  
pp. 190136 ◽  
Author(s):  
Xin Li ◽  
Weiwen Wang ◽  
Pan Zhang ◽  
Jianlong Li ◽  
Guanghui Chen
Keyword(s):  
Mass Transfer ◽  
Bubble Diameter ◽  
Water System ◽  
Mass Transfer Process ◽  
Liquid Mass ◽  
Fluid Field ◽  
Vof Model ◽  
Liquid Mass Transfer ◽  
The Relationship ◽  
Two Sides

Interactions between gas–liquid mass transfer and bubble behaviours were investigated to improve the understanding of the relationship between the two sides. The CO 2 /N 2 -water system was applied to study the bubble behaviours based on the volume-of-fluid (VOF) model. The mass transfer conditions were taken into consideration when the fluid field was analysed. The bubble behaviours were compared with and without mass transfer. The results show that the absolute slopes of the curves for mass fraction inside the single rising bubbles, with diameters from 3 to 6 mm, decrease from 0.09325 to 0.02818. It means that small single bubbles have higher mass transfer efficiency. The daughter bubbles of cutting behaviour and initial side-by-side bubbles of coalescence behaviour also perform better than the initial large bubbles and coalesced bubbles, respectively. The bubble behaviours affect the mass transfer process. However, the latter also reacts upon the former. The critical intervals between the side-by-side bubbles decrease from 2.0 to 0.9 mm when the bubble diameter changes from 3 to 7 mm. For the coalescence behaviour without mass transfer, the critical intervals are larger because there is no influence of concentration around the bubbles on the bubble motion. The coalescence of cut daughter bubbles is also influenced by the concentration. It was suggested that the interaction between the gas–liquid mass transfer and bubble behaviours cannot be ignored.

CFD modeling of gas–liquid mass transfer process in a rotating packed bed

2016 ◽  
Vol 294 ◽  
pp. 111-121 ◽  
Author(s):  
Yucheng Yang ◽  
Yang Xiang ◽  
Guangwen Chu ◽  
Haikui Zou ◽  
Baochang Sun ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Process ◽  
Mass Transfer Process ◽  
Packed Bed ◽  
Cfd Modeling ◽  
Liquid Mass ◽  
Rotating Packed Bed ◽  
Liquid Mass Transfer

scholarly journals Ultrasonic Investigation of Hydrodynamics and Mass Transfer in a Gas-Liquid(-Liquid) Stirred Vessel

2005 ◽  
Vol 3 (1) ◽  
Author(s):  
A.H.G. Cents ◽  
D.W.F. Brilman ◽  
G.F. Versteeg
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Water System ◽  
Interfacial Area ◽  
Volumetric Mass Transfer Coefficient ◽  
Volume Fractions ◽  
Liquid Mass ◽  
Liquid Mass Transfer ◽  
Transfer Parameters

The rate of gas-liquid mass transfer is very important in several industrial chemical engineering applications. In many multi-phase reaction systems, however, the mechanism of mass transfer is not well understood. This is for instance the case in Gas-Liquid-Solid (G-L-S) and Gas-Liquid-Liquid (G-L-L) systems. To obtain more knowledge of the mechanism of mass transfer, the mass transfer coefficient, kL, and the interfacial area, a, should be studied separately. In this work an ultrasonic measurement technique is used to study the local interfacial area in a standard sized vessel, equipped with a Rushton type impeller. This is done in combination with experimental determination of the volumetric mass transfer coefficient, kLa, using the dynamic oxygen method, to obtain values for kL. The gas hold-up is determined additionally to obtain values for the Sauter mean bubble diameter at different positions in the vessel. In a coalescing air-water system the bubble size was non-uniform throughout the vessel and increased from small bubbles at the impeller along with the flow pattern to larger sizes in the bulk of the vessel. In a non-coalescing electrolyte system the vessel was much more uniform and the bubbles were smaller when compared to the air-water system. To obtain overall values of the mass transfer parameters the local values were integrated according to their volume fraction in the reactor. In both coalescing and non-coalescing systems the overall values for the mass transfer parameters were in good agreement with literature correlations. The addition of small volume-fractions of toluene to an air-water system caused a strong decrease in both the volumetric mass transfer coefficient and in the gas hold-up. The interfacial area increased, however, but it was shown that this was due to the presence of microbubbles in the solution, which do not take part in the mass transfer process. The enhancing effect on gas-liquid mass transfer due to the addition of larger volume-fractions of toluene could be described reasonably well by a homogeneous model of the shuttle mechanism.

scholarly journals Analysis of Nonlinear Dynamics for Abrupt Change of Interphase Structure in Liquid-Liquid Mass Transfer

2009 ◽  
Vol 2009 ◽  
pp. 1-13
Author(s):  
DongXiang Zhang ◽  
Min Sun ◽  
Jing Li
Keyword(s):  
Mass Transfer ◽  
Molecular Diffusion ◽  
Abrupt Change ◽  
Mass Transfer Rate ◽  
Mass Transfer Process ◽  
Liquid System ◽  
Phase Portraits ◽  
Liquid Mass ◽  
Liquid Mass Transfer ◽  
Parameter Ranges

As a liquid-liquid system is far from equilibrium state, the phase thickness is variable when mass transfer process with chemical reaction occurs in interphase zone, and a dispersible transitional layer called the interphase dispersed zone (IDZ) is formed. The IZD model composed of thermodynamically instable O/W or W/O microemulsion has reasonably explained enormous experimental phenomena in nonlinear mass transfer. To forecast the possible parameter ranges of IDZ process and abrupt change of liquid-liquid mass transfer rate, the dynamic characteristics of a molecular diffusion model are considered in this paper. We applied the bifurcation theory of planar dynamical system, Laplace transform, and maple software to investigate the model, and obtain different phase portraits of the system in different regions. The results obtained will play an important directive role in the study of IDZ model.

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