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.

Mass Transfer From Single Carbon Dioxide Bubbles in Contaminated Water

2014 ◽  
Author(s):  
Jiro Aoki ◽  
Kosuke Hayashi ◽  
Shogo Hosoda ◽  
Shigeo Hosokawa ◽  
Akio Tomiyama
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Surfactant Concentration ◽  
Bubble Diameter ◽  
Surfactant Solution ◽  
Contaminated Water ◽  
Tail Region ◽  
Transfer Rates ◽  
Small Bubbles ◽  
Taylor Bubbles

Mass transfer from single carbon dioxide bubbles rising through contaminated water in a vertical pipe of 12.5 mm diameter was measured to investigate effects of surfactant. The bubble diameter was widely varied to cover various bubble shapes such as spheroidal, wobbling, cap and Taylor bubbles. The gas and liquid phases were 99.9 % purity carbon dioxide and a surfactant solution made of purified water and Triton X-100. Comparison of mass transfer rates between contaminated and clean bubbles made clear that the surfactant decreases the mass transfer rates of small bubbles. The Sherwood number of small bubbles in the extreme cases, i.e. zero and the highest surfactant concentrations, is well correlated in terms of the bubble Reynolds number, Schmidt number and the ratio, λ, of the bubble diameter to pipe diameter. The Sherwood numbers at intermediate surfactant concentration, however, are not well correlated using available correlations. The mass transfer rates of Taylor bubbles also decrease with increasing the surfactant concentration. They however increase with the diameter ratio and approaches that of clean Taylor bubbles as λ increases. The main cause of this tendency was revealed by interface tracking simulations, i.e. the surfactant adsorbs only in the bubble tail region and the nose-to-side region is almost clean at high λ.

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.

Assessment of Components of the Subcooled Boiling Model for CFD Simulations

2010 ◽  
Author(s):  
Deoras Prabhudharwadkar ◽  
Martin A. Lopez de Bertodano ◽  
John Buchanan ◽  
Avinash Vaidheeswaran
Keyword(s):  
Fluid Model ◽  
Constitutive Relations ◽  
Bubble Diameter ◽  
Density Ratio ◽  
Data Sets ◽  
Vapor Generation ◽  
Wide Range ◽  
Two Fluid Model ◽  
Bubble Sizes ◽  
Two Fluid

This paper describes the details of validation of heat and mass transfer models used for subcooled boiling simulation with a CFD two-fluid model. This research was focused on assessment of the wall heat flux partitioning model using the state-of-the-art multidimensional experimental data available in the literature. Various constitutive relations used to close the vapor generation rate at the heated wall were studied and the best suited combination of these was obtained. The current study was restricted to vertical flows through pipe and annulus geometries. Three data sets from the literature were considered: first with R12 at about 26 bar pressure, second with water at atmospheric pressure and third with R113 at 2.69 bar pressure. In these data sets, the bubble diameter distribution across the ducts was measured. Bubble diameter estimation brings in the largest uncertainty in the two-fluid model predictions and hence using the data with known bubble sizes allowed to focus on assessment of other parameters which use constitutive relations to model vapor generation rate, e.g. bubble nucleation site density and bubble departure frequency at the wall. The simulations were carried out using the CFD code CFX-12. The R12 data used here corresponds to fluid-vapor density ratio which is equivalent to that of water-steam at 150 bar. Therefore the density ratio varies over two orders of magnitude. The surface tension also varies over a wide range from 0.0017 to 0.057 N/m. The ratio of the flow channel hydraulic diameter to the bubble diameter in these simulations varied between 4 and 40. The two-fluid model was modified, for cases involving bubble sizes too large to be represented using the continuum assumption, in order to obtain satisfactory results. Hence, the model that has been developed for this study is applicable for a wide range of physical conditions and bubble sizes.

scholarly journals Carbon dioxide dissolution in structural and stratigraphic traps

2013 ◽  
Vol 736 ◽  
pp. 287-315 ◽  
Author(s):  
M. L. Szulczewski ◽  
M. A. Hesse ◽  
R. Juanes
Keyword(s):  
Carbon Dioxide ◽  
Anthropogenic Emissions ◽  
Exchange Flow ◽  
Geologic Sequestration ◽  
Reservoir Properties ◽  
Wide Range ◽  
Subsurface Geometry ◽  
Rayleigh Numbers ◽  
Finite Extent

AbstractThe geologic sequestration of carbon dioxide ( CO2) in structural and stratigraphic traps is a viable option to reduce anthropogenic emissions. While dissolution of the CO2 stored in these traps reduces the long-term leakage risk, the dissolution process remains poorly understood in systems that reflect the appropriate subsurface geometry. Here, we study dissolution in a porous layer that exhibits a feature relevant for CO2 storage in structural and stratigraphic traps: a finite CO2 source along the top boundary that extends only part way into the layer. This feature represents the finite extent of the interface between free-phase CO2 pooled in a trap and the underlying brine. Using theory and simulations, we describe the dissolution mechanisms in this system for a wide range of times and Rayleigh numbers, and classify the behaviour into seven regimes. For each regime, we quantify the dissolution flux numerically and model it analytically, with the goal of providing simple expressions to estimate the dissolution rate in real systems. We find that, at late times, the dissolution flux decreases relative to early times as the flow of unsaturated water to the CO2 source becomes constrained by a lateral exchange flow though the reservoir. Application of the models to several representative reservoirs indicates that dissolution is strongly affected by the reservoir properties; however, we find that reservoirs with high permeabilities ($k\geq 1$ Darcy) that are tens of metres thick and several kilometres wide could potentially dissolve hundreds of megatons of CO2 in tens of years.

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.

Mass transfer of water vapor, carbon dioxide and oxygen on modified cellulose fiber-based materials

2012 ◽  
Vol 27 (2) ◽  
pp. 409-417 ◽  
Author(s):  
Alemayehu H. Bedane ◽  
Qinglin Huang ◽  
Huining Xiao ◽  
Mladen
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Water Vapor ◽  
Relative Humidity ◽  
Transmission Rate ◽  
The Other ◽  
Paper Sample ◽  
Coated Paper ◽  
Wide Range ◽  
Transfer Properties

Abstract Mass transfer properties of fibre network and coated paper are essential for understanding the barrier properties of the products and further advance in their application. In this study, different unmodified and coated papers, e.g., (Poly lactic acid (PLA), zein grafted paper) were prepared and characterized with regard to mass transfer properties. Water vapor, carbon dioxide (CO2) and oxygen (O2) transmission rates through the cellulose paper films were measured and the results discussed. The effects of sample film thickness and samples were found to be strongly dependent on the temperature and the relative humidity difference (mass transfer driving force). On the other hand water vapor permeabilities relative humidity. Water vapor diffusivities of the samples were also measured from the uptake rate measurements using Fickian diffusion slab model for a wide range of relative modified samples were found to be generally low compared to unmodified (reference) paper sample. Among the investigated samples, PLA/polyhedral oligomeric silsesquioxane POSS-bentonite modified paper sample showed higher mass transfer resistance to water vapour and the gases investigated in this study (CO2and O2). It showed lower water transmission rate (104 g/m2.day) compared to PLA-coated paper (130 g/m2.day), zein coated paper (179 g/m2.day) and control sample (359 g/m2.day) at the relative humidity gradient RH=74% and temperature of 25 oC. The oxygen transmission rate for PLA/(POSS-Bentonite) coated paper was found to be lower than for the other modified papers. Zein grafted paper showed better barrier property for water vapor than oxygen. Water vapor permeation through paper films shows an Arrhenius type of dependency with temperature, indicating activated process. The activation energies reveal diffusion dominated process for all paper samples investigated in this study, according to the solution-diffusion mechanism used to describe the permeation processes.

scholarly journals THE ESTIMATION OF GHG EMISSIONS FOR HOTELS IN ASIAN INSTITUTE OF TECHNOLOGY AND CHIANG MAI HILL 2000, THAILAND

2015 ◽  
Vol 1 (1) ◽  
pp. 1 ◽  
Author(s):  
Luansak Supansa
Keyword(s):  
Climate Change ◽  
Carbon Dioxide ◽  
Hotel Industry ◽  
Ghg Emissions ◽  
Low Carbon ◽  
Chiang Mai ◽  
Short Term ◽  
Wide Range ◽  
Institute Of Technology

In the tourism sector, hotel industry is one of the most important sub-sector. This hotel industry emits greenhouse gas (GHG) emissions mainly carbon dioxide (CO2) by consuming large amount of energy, water, and non-renewable resources in service operation everyday on basis. This paper presents results of analysis how much does the GHG emissions release in hotel. The Asian Institute of Technology Conference Center and Chiang Mai Hill 2000, Chiang Mai, Thailand have successfully estimated GHG emissions by using Bilan Carbone® tool. The mitigation options are to encourage low carbon dioxide hotels. The data collection was done by questionnaires, interviews, and observations in both of them hotels. The results of annual GHG emissions contributor both Chiang Mai Hill 2000 as 3,844 t CO2 and at AITCC about 1,011 t CO2. Energy use is a major emission contributor followed by travel, property, input material, waste generated, and freight. Higher number of guests/tourists flow, effected higher used of facilities such as electricity, air conditioning, lighting, and food & beverage. Larger size hotel service quality, greater guest room service, wide range of building area, greater facilities, and large functional are consumed higher energy and materials. As well as, the higher rate of room turning can also increase of emissions. Moreover, Chiang Mai Hill 2000 tends to take transportation which have longer distance than AITCC. Therefore, increasing higher journal distance generated higher GHG emissions as well. The short term and long term mitigation plans can also be taken into consideration to reduce GHG emissions. The recommendation of short term mitigation plans can be applied directly in both hotels thus, increasing awareness about climate change and energy conservation among uses. The long term mitigation plans recommends to give “Green Hotel” award to successful hotels for reducing GHG emissions in hotel. These plans can be incorporated the Thailand’s government policy to reduce the impacts of climate change to the hotel industry. 

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