scholarly journals Experimental research of mass transfer in a stabilized foam layer

ScienceRise ◽  
2021 ◽  
pp. 14-22
Author(s):  
Viktor Moiseev ◽  
Eugenia Manoilo ◽  
Oleg Khukhryanskiy ◽  
Kalif Repko
Keyword(s):  
Mass Transfer ◽  
Cross Section ◽  
Contact Element ◽  
Gas Content ◽  
Foam Layer ◽  
Gas Velocity ◽  
Hydrodynamic Mode ◽  
Gas Emissions ◽  
Technological Processes ◽  
Technological Product

The object of research: mass transfer processes on a combined contact element in a column apparatus. Investigated problem: determination of the regularities of process parameters in the processing of gas-liquid systems in a foam layer, as well as to interpret the obtained experimental data. The problem of processing industrial gas flows is solved by conducting the process in an intensive mode. The main scientific results: as a result of the study, the regularities of ammonia absorption were revealed depending on the main parameters of the experiment: gas velocity in the column cross-section, ammonia concentration, free cross-section of the combined contact element, and liquid loads. The process of mass transfer in the gas phase is significantly influenced by hydrodynamic parameters – the gas velocity in the apparatus and the specific load on the liquid, which indirectly affect the height of the liquid layer on the plate and the gas content of the layer. The area of practical use of the research results: sorption processes for processing gases and liquids in technological processes, absorption of harmful substances in the treatment of gas emissions. Innovative technological product: new block poppet-nozzle contact device that operates in a stabilized hydrodynamic mode; new ball-shaped weighted nozzle for three-phase foam layer. Scope of application the innovative technological product: technological processes in the treatment of gas emissions or technological gases.

Mass transfer into the liquid in turbulent flow at high Schmidt numbers. Dissolution of benzoic acid into aqueous solutions of glycerol from internal surface of the pipe

1981 ◽  
Vol 46 (7) ◽  
pp. 1566-1576
Author(s):  
František Vašák ◽  
Václav Kolář ◽  
Zdeněk Brož
Keyword(s):  
Mass Transfer ◽  
Benzoic Acid ◽  
Aqueous Solutions ◽  
Cross Section ◽  
Circular Cross Section ◽  
Internal Surface ◽  
Theoretical Relation ◽  
Acid Dissolution ◽  
Schmidt Numbers ◽  
Unified Description

Theoretical relation derived in the last study for calculation of the mass transfer coefficient in the region of not fully developed concentration profile at high Schmidt numbers has been verified experimentally. This experimental study has been devoted to measurements of the rate of benzoic acid dissolution into aqueous solutions of glycerol from the internal surface of the pipe of circular cross section in the range 933 ⪬ Sc ⪬ 225 000 and 5 000 ⪬ Re ⪬ 50 000. It has been possible to explain on basis of the theoretical model, the differences between the data of various authors and to obtain a unified description of the phenomena.

scholarly journals Hydrodynamics and Mass Transfer in a Concentric Internal Jet-Loop Airlift Bioreactor Equipped with a Deflector

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4329
Author(s):  
Radek Šulc ◽  
Jan Dymák
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Liquid System ◽  
Gas Holdup ◽  
Gas Velocity ◽  
Liquid Phase Mass Transfer ◽  
Homogenization Time ◽  
Standard Design ◽  
Superficial Gas Velocity

The gas–liquid hydrodynamics and mass transfer were studied in a concentric tube internal jet-loop airlift reactor with a conical bottom. Comparing with a standard design, the gas separator was equipped with an adjustable deflector placed above the riser. The effect of riser superficial gas velocity uSGR on the total gas holdup εGT, homogenization time tH, and overall volumetric liquid-phase mass transfer coefficient kLa was investigated in a laboratory bioreactor, of 300 mm in inner diameter, in a two-phase air–water system and three-phase air–water–PVC–particle system with the volumetric solid fraction of 1% for various deflector clearances. The airlift was operated in the range of riser superficial gas velocity from 0.011 to 0.045 m/s. For the gas–liquid system, when reducing the deflector clearance, the total gas holdup decreased, the homogenization time increased twice compared to the highest deflector clearance tested, and the overall volumetric mass transfer coefficient slightly increased by 10–17%. The presence of a solid phase shortened the homogenization time, especially for lower uSGR and deflector clearance, and reduced the mass transfer coefficient by 15–35%. Compared to the gas–liquid system, the noticeable effect of deflector clearance was found for the kLa coefficient, which was found approx. 20–29% higher for the lowest tested deflector clearance.

Studying the Effect of Fuel Elements Structural Materials Corrosion on their Operating Life

2021 ◽  
Vol 1038 ◽  
pp. 108-115
Author(s):  
Yuliana Hapon ◽  
Maksym Kustov ◽  
Volodumur Kalugin ◽  
Alexander Savchenko
Keyword(s):  
Experimental Data ◽  
Mass Transfer ◽  
Fuel Element ◽  
State Level ◽  
External Factors ◽  
Economic Losses ◽  
Operating Life ◽  
Hydrodynamic Mode ◽  
Internal And External Factors ◽  
Fuel Elements

The paper deals with experimental data regarding the effect of internal and external factors on the corrosion decay of Zr1Nb alloy fuel elements. Based on the analysis results, losses of zirconium that transfers to oxide or coolant as per the fuel element wall weight and thickness as well as economic losses from their corrosion decay have been theoretically calculated. To avoid a state-level emergency occurrence, an increase in the fuel element wall thickness up to 660 μm is proposed, which can increase the operating life under the conditions of trouble-free coolant mass transfer hydrodynamic mode.

scholarly journals Numerical study of the hydrodynamics and mass transfer in the external loop airlift reactor

2021 ◽  
pp. 34-34
Author(s):  
Predrag Kojic ◽  
Jovana Kojic ◽  
Milada Pezo ◽  
Jelena Krulj ◽  
Lato Pezo ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Airlift Reactor ◽  
Volumetric Mass Transfer Coefficient ◽  
Cfd Model ◽  
Gas Velocity ◽  
Liquid Mass ◽  
External Loop ◽  
Liquid Mass Transfer

The objective of this study was to investigate the hydrodynamics and the gas-liquid mass transfer coefficient of an external-loop airlift reactor (ELAR). The ELAR was operated in three cases: different inlet velocities of fluids, different alcohols solutions (water, 0.5% methanol, 0.5% ethanol, 0.5% propanol and 0.5% butanol) and different concentration of methanol in solutions (0%, 0.5%, 1%, 2% and 5%). The influence of superficial gas velocity and various diluted alcohol solutions on hydrodynamics and gas-liquid mass transfer coefficient of the ELAR was studied. Experimentally, the gas hold-up, liquid velocities and volumetric mass transfer coefficient values in the riser and the downcomer were obtained from the literature source. A computational fluid dynamics (CFD) model was developed, based on two-phase flow, investigating different liquids regarding surface tension, assuming the ideal gas flow, applying the finite volume method and Eulerian-Eulerian model. The volumetric mass transfer coefficient was determined using CFD model, as well as artificial neural network model. The effects of liquid parameters and gas velocity on the characteristics of the gas-liquid mass transfer were simulated. These models were compared with appropriate experimental results. CFD model successfully succeed to simulate the influence of different alcohols regarding the number of C-atoms on hydrodynamics and mass transfer.

Heat and Mass Transfer in Capillary-Pumped Liquid Films in Square Cross-Section Minichannels

2008 ◽  
Vol 29 (11) ◽  
pp. 913-923 ◽  
Author(s):  
Valérie Serin ◽  
Béatrice Médéric ◽  
Pascal Lavieille ◽  
Marc Miscevic
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Cross Section ◽  
Liquid Films

scholarly journals Computational Study of Zigzag Spacer Design with Elliptical Cross-Section Filaments

2020 ◽  
Vol 307 ◽  
pp. 01047
Author(s):  
Gohar Shoukat ◽  
Farhan Ellahi ◽  
Muhammad Sajid ◽  
Emad Uddin
Keyword(s):  
Mass Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Computational Study ◽  
Flow Direction ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Two Dimensional ◽  
Permeate Flux ◽  
Elliptical Cross

The large energy consumption of membrane desalination process has encouraged researchers to explore different spacer designs using Computational Fluid Dynamics (CFD) for maximizing permeate per unit of energy consumed. In previous studies of zigzag spacer designs, the filaments are modeled as circular cross sections in a two-dimensional geometry under the assumption that the flow is oriented normal to the filaments. In this work, we consider the 45° orientation of the flow towards the three-dimensional zigzag spacer unit, which projects the circular cross section of the filament as elliptical in a simplified two-dimensional domain. OpenFOAM was used to simulate the mass transfer enhancement in a reverse-osmosis desalination unit employing spiral wound membranes lined with zigzag spacer filaments. Properties that impact the concentration polarization and hence permeate flux were analyzed in the domain with elliptical filaments as well as a domain with circular filaments to draw suitable comparisons. The range of variation in characteristic parameters across the domain between the two different configurations is determined. It was concluded that ignoring the elliptical projection of circular filaments to the flow direction, can introduce significant margin of error in the estimation of mass transfer coefficient.

Natural Convection Heat and Mass Transfer From a Horizontal Cylinder of Elliptic Cross Section with Constant Wall Temperature and Concentration in Saturated Porous Media

2006 ◽  
Vol 22 (3) ◽  
pp. 257-261 ◽  
Author(s):  
C.-Y. Cheng
Keyword(s):  
Mass Transfer ◽  
Natural Convection ◽  
Heat And Mass Transfer ◽  
Cross Section ◽  
Wall Temperature ◽  
Horizontal Cylinder ◽  
Elliptic Cross Section ◽  
Convection Heat ◽  
Constant Wall Temperature ◽  
Elliptic Cross

AbstractThis work studies the natural convection heat and mass transfer near a horizontal cylinder of elliptic cross section with constant wall temperature and concentration in a fluid-saturated porous medium. A coordinate transformation is used to obtain the nonsimilar governing boundary layer equations. The transformed governing equations are then solved by the cubic spline collocation method. Results for the local Nusselt and Sherwood numbers are presented as functions of the Lewis number, the buoyancy ratio, and the aspect ratio when the major axis of the elliptical cylinder is vertical (slender orientation) and horizontal (blunt orientation). The heat and mass transfer rates of the elliptical cylinder with slender orientation are higher than those with blunt orientation.

Mass Transfer Studies in a Novel Perforated Plate Bubble Column

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
S. Dhanasekaran ◽  
T. Karunanithi
Keyword(s):  
Mass Transfer ◽  
Liquid Velocity ◽  
Bubble Column ◽  
Perforated Plate ◽  
Gas Velocity ◽  
Plate Spacing ◽  
Mass Transfer Studies ◽  
Superficial Gas Velocity ◽  
Superficial Liquid Velocity

This investigation reports the experimental and theoretical results carried out to evaluate the volumetric mass transfer coefficient (kLa) in a novel hybrid rotating and reciprocating perforated plate bubble column. Countercurrent condition is performed. kLa is studied by the absorption of oxygen from air into deoxygenated water at room temperature (27 ± 1°C). Effects of agitation level, superficial gas velocity, superficial liquid velocity and plate spacing on kLa were analyzed and found to be significant. With an increase in agitation level at a constant superficial gas and liquid velocities, the breakage process of gas bubbles starts to be more pronounced and intensive oxygen mass transfer occurs. Hence, kLa increases sharply. kLa increases with an increase in superficial gas velocity, due to higher gas holdup and the enhanced breakup of bubbles. Similarly, kLa increases with an increase in superficial liquid velocity and the effect is found to be significant. When plate spacing is decreased (by increasing the number of plates), it is observed that the kLa increases at higher superficial gas velocity and agitation level. Correlation is developed for the determination of kLa and found to concur with experimental results. This correlation can be used for the determination of kLa for this hybrid column with 95% accuracy within the range of variables investigated in this present study.

Automatic Control of Operating Modes of Packed Apparatus for Selective Gas Emissions Cleaning

2020 ◽  
Vol 24 (2) ◽  
pp. 10-16 ◽  
Author(s):  
N.A. Merentsov ◽  
A.V. Persidsky ◽  
V.N. Lebedev ◽  
A.B. Golovanchikov
Keyword(s):  
Mass Transfer ◽  
Automatic Control ◽  
Mass Transfer Process ◽  
Automatic Regulation ◽  
Gas Emissions ◽  
Automatic Adjustment ◽  
Operating Modes ◽  
Mass Transfer Processes ◽  
Metal Chips ◽  
Main Operating

A modified system for automatic control of hydrodynamic operating modes of packed adsorption columns for the selective cleaning of gas emissions is described, which allows automatic adjustment of the operating modes of packed mass transfer apparatus. Presents the scheme and algorithm of developed system with the automatic adjustment (calibration) mode of main operating parameters. The main features and advantages of using elastically deformable blocks of packed material are given on the example of metal chips, i.e. waste of machine tools as a packed material that meet all requirements of the ongoing mass transfer processes and are amenable to automated regulation. The developed system of automatic regulation of parameters of packed units, but also to solve a very serious environmental problem of industrial waste recovery. A classification technique of studying the hydrodynamics of packed materials, capable of concluding the suitability of this sample of packing material for a specific mass transfer process, in particular the adsorption process for the selective cleaning of gas emissions.

ELECTROCHEMICAL AND COMBINED TREATMENT IN RHEOLOGICAL FLUID

2020 ◽  
pp. 3-6
Author(s):  
V. P. Smolentsev ◽  
E. V. Kotukov ◽  
N. V. Pishkova
Keyword(s):  
Mass Transfer ◽  
Cross Section ◽  
Combined Treatment ◽  
Small Cross Section ◽  
Working Environments ◽  
Coupling Path ◽  
Experimental Works ◽  
Metal Materials ◽  
Required Quality

Questions of search and assignment of working environments are considered, providing stabilization of processes of erosion-chemical and electrochemical dimensional processing at production of deep apertures in metal materials and ceramics. It is shown that the use of rheological fluids with nanoparticles of conductive granules can accelerate the mass transfer of processing products. It is established that when using rheological fluids it is possible to provide the required quality of the surface layer of deep through and blind channels of small cross-section. Experimental works on multielectrode flashing of round and polyhedral channels were carried out, which allowed to develop technological processes of manufacture of the sections of the coupling path for supplying combustible media to a combustion zone.

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