Interface Tracking Simulation of Mass Transfer From a Dissolving Bubble

2011 ◽  
Author(s):  
Kosuke Hayashi ◽  
Akio Tomiyama
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Volume Change ◽  
Empirical Models ◽  
Interface Tracking ◽  
Vertical Pipe ◽  
Transfer Coefficients ◽  
Species Concentration ◽  
Tracking Method ◽  
Benchmark Tests

An interface tracking method for predicting bubble dissolution process is proposed. A non-diffusive scheme for advecting species concentrations is adopted to accurately compute the volume change due to mass transfer. The applicability of the proposed method is examined through several benchmark tests, i.e. mass transfer from a static bubble and that from free rising bubbles. Predicted species concentration distributions and mass transfer coefficients agree well with theoretical and empirical models. Dissolution of single carbon dioxide bubbles in a vertical pipe filled with water is also simulated. The bubbles consist only of carbon dioxide, and nitrogen and oxygen are initially dissolved in water. The volume change due to dissolution of carbon dioxide from the bubbles and evaporation of nitrogen and oxygen from water are well predicted.

Dissolution of a Carbon Dioxide Bubble in a Vertical Pipe

2007 ◽  
Author(s):  
Satoru Abe ◽  
Hideaki Okawa ◽  
Shigeo Hosokawa ◽  
Akio Tomiyama
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Reynolds Number ◽  
Relative Velocity ◽  
Bubble Diameter ◽  
Bulk Liquid ◽  
Vertical Pipe ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Millipore Water

Dissolution of single carbon dioxide (CO2) bubbles in a vertical pipe of 25 mm in diameter are measured to examine the effects of the ratio λ of sphere–volume equivalent bubble diameter d to pipe diameter D, liquid Reynolds number ReL and surfactants on mass transfer. The bubble diameter d and Reynolds number ReL are varied from 5.0 to 26 mm (λ = 0.20 − 1.0) and from 0 to 3100, respectively. Millipore water, tap water and water contaminated with Triton X–100 are used for the liquid phase. Mass transfer coefficients kL are evaluated from changes in d. The kL decreases with increasing λ for bubbles in stagnant millipore water because of the decrease in bubble rising velocity due to the wall effect. Measured Sherwood numbers Sh do not depend on ReL because a turbulent fluctuation velocity in bulk liquid flow is much smaller than a relative velocity between a bubble and liquid. The mass transfer correlation for a bubble in a stagnant liquid proposed by Johnson et al. is applicable to a bubble in pipe flow, provided that a correct relative velocity between a bubble and liquid is substituted in the correlation. Due to the retardation of capillary wave, mass transfer coefficients for bubbles in contaminated water becomes smaller than those in millipore and tap waters.

Mass Transfer From a Bubble in a Vertical Pipe

2011 ◽  
Author(s):  
Shogo Hosoda ◽  
Ryosuke Sakata ◽  
Kosuke Hayashi ◽  
Akio Tomiyama
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Bubble Diameter ◽  
Vertical Pipe ◽  
Oblate Spheroidal ◽  
Wide Range ◽  
Bubble Sizes ◽  
Small Bubbles ◽  
Taylor Bubbles

Mass transfer from single carbon dioxide bubbles in a vertical pipe is measured using a stereoscopic image processing method to develop a mass transfer correlation applicable to a wide range of bubble and pipe diameters. The pipe diameters are 12.5, 18.2 and 25.0 mm and the bubble diameter ranges from 5 to 26 mm. The ratio, λ, of bubble diameter to pipe diameter is therefore varied from 0.2 to 1.8, which covers various bubble shapes such as spherical, oblate spheroidal, wobbling, cap, and Taylor bubbles. Measured Sherwood numbers, Sh, strongly depend on bubble shape, i.e., Sh of Taylor bubbles clearly differs from those of spheroidal and wobbling bubbles. Hence two Sherwood number correlations, which are functions of the Peclet number and the diameter ratio λ, are deduced from the experimental data: one is for small bubbles (λ < 0.6) and the other for Taylor bubbles (λ > 0.6). The applicability of the proposed correlations for the prediction of bubble dissolution process is examined through comparisons between measured and predicted long-term bubble dissolution processes. The predictions are carried out by taking into account the presence of all the gas components in the system of concern, i.e. nitrogen, oxygen and carbon dioxide. As a result, good agreements for the dissolution processes for various bubble sizes and pipe diameters are obtained. It is also demonstrated that it is possible to evaluate an equilibrium bubble diameter and instantaneous volume concentration of carbon dioxide in a bubble using a simple model based on a conservation of gas components.

Experimental Investigation of Enhanced Absorption of Carbon Dioxide in Diethanolamine in a Microreactor

2013 ◽  
Author(s):  
Harish Ganapathy ◽  
Amir Shooshtari ◽  
Serguei Dessiatoun ◽  
Mohamed Alshehhi ◽  
Michael M. Ohadi
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Natural Gas ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Absorption Efficiency ◽  
Optimum Operating ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Liquid Absorption

Natural gas in its originally extracted form comprises carbon dioxide and hydrogen sulfide as small, but non-negligible fractions of its dominant component, methane. Natural gas in the above form is typically subjected to a sweetening process that removes these acid gases. Microscale technologies have the potential to substantially enhance mass transport phenomena on account of their inherently high surface area to volume ratio. The present work reports the mass transfer characteristics during gas-liquid absorption in a microreactor. The absorption of CO2 mixed with N2 into aqueous diethanolamine was investigated in a single straight channel having a hydraulic diameter of 762 micrometer and circular cross-sectional geometry. The performance of the reactor was characterized with respect to the absorption efficiency and mass transfer coefficient. Close to 100% absorption efficiency was obtained under optimum operating conditions. Shorter channel lengths were observed to yield enhanced values of mass transfer coefficient on account of the improved utilization of the liquid reactants’ absorption capacity for a given reactor volume. In comparison to the 0.5 m long channel, the mass transfer coefficients with the 0.3 m and 0.1 m channels were higher on an average by 35.2% and 210%, respectively. Parametric studies investigating the effects of phase superficial velocity, liquid and gas phase concentration were performed. The mass transfer coefficients achieved using the present minichannel reactor were 1–3 orders of magnitude higher than that reported using conventional gas-liquid absorption systems.

Simulation of the Coalescence of two Bubbles Rising in a Vertical Pipe with VOF Interface Tracking Method

2007 ◽  
Author(s):  
Djemai Merrouche ◽  
Kamal Mohammedi ◽  
Idir Belaidi ◽  
Bachir Mabrouki
Keyword(s):  
Interface Tracking ◽  
Vertical Pipe ◽  
Tracking Method ◽  
Two Bubbles

Enhanced Mass Transfer Rates in Nanofluids: Experiments and Modeling

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Ratnesh U. Khanolkar ◽  
A. K. Suresh
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Particle Size ◽  
Capillary Tube ◽  
Carbon Dioxide Absorption ◽  
Transfer Coefficients ◽  
Material Density ◽  
Transfer Rates ◽  
Low Volume ◽  
Wetted Wall Column

Enhancement in carbon dioxide absorption in water has been studied using SiO2 and TiO2 nanoparticles using the capillary tube apparatus for which previous results on Fe3O4 nanoparticles were reported earlier. Enhancements of up to 165% in the mass transfer coefficients were observed at fairly low volume fractions of the particles. A model which accounts for the effect of particles in terms of a superimposed convection has been proposed to explain the observed effects of particle size, hold-up, and material density. The model provides a good fit to the data from wetted wall column and capillary tube experiment for Fe3O4 from the previous literature, as well as for the data from this work.

An Interface Tracking Method Based on Volume Tracking in Embedded Micro Cells

2002 ◽  
Author(s):  
Akio Tomiyama ◽  
Yusuke Nakahara ◽  
Satoru Abe
Keyword(s):  
Surface Tension ◽  
Density Ratio ◽  
Surface Tension Force ◽  
Interface Tracking ◽  
Air Bubbles ◽  
Interface Thickness ◽  
Vertical Pipe ◽  
Stagnant Water ◽  
Tracking Method ◽  
High Density Ratio

An interface tracking method based on volume tracking in micro cells embedded in regular cells is proposed. The volume tracking is based on a CIP scheme, which yields extremely sharp and jaggy interface in micro cells. However, in regular cells, the jagged interface is smoothed and the interface thickness becomes comparable to a regular cell size Δx. Single air bubbles in stagnant water and single large air bubbles in stagnant water filled in a vertical pipe are simulated with the proposed method. As a result, it is confirmed that (1) the proposed method conserves bubble volumes, (2) the interface thickness around a bubble is kept within 2Δx, and thereby the surface tension force is well evaluated by the CSF model, and (3) the method can give good predictions for bubbles in a high density-ratio system.

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