Dimensionless Groups in the Modeling and Prediction of Corrosion Processes

CORROSION ◽  
1985 ◽  
Vol 41 (12) ◽  
pp. 679-687 ◽  
Author(s):  
D. C. Silverman
Keyword(s):  
Mass Transfer ◽  
Mass Transport ◽  
Transfer Rate ◽  
Reaction Rate ◽  
Surface Reaction ◽  
Mass Transfer Rate ◽  
Localized Corrosion ◽  
Flow Conditions ◽  
Modeling And Prediction ◽  
Dimensionless Groups

Abstract Coupled differential equations that are difficult to solve, yet have predictive value, will arise when modeling a combination of general and localized corrosion in the presence of flow. These equations are impossible to solve if the flow is turbulent. By making the equations dimensionless, certain groups arise that can show the relative magnitudes of the processes involved. Three dimensionless groups arise from modeling the localized area. These show the ratios of the magnitudes of migration to diffusion, convective mass transport to diffusive mass transport, and surface reaction rate to mass transfer rate. The meanings of the groups are independent of geometry and flow conditions. These groups can provide a “back-of-the-envelope” type of guidance for experimental design and corrosion prediction even though the equations from which they are derived cannot be solved.

scholarly journals Ozone mass transfer behaviors on physical and chemical absorption for hollow fiber membrane contactors

2017 ◽  
Vol 76 (6) ◽  
pp. 1360-1369 ◽  
Author(s):  
Yong Zhang ◽  
Kuiling Li ◽  
Jun Wang ◽  
Deyin Hou ◽  
Huijuan Liu
Keyword(s):  
Mass Transfer ◽  
Hollow Fiber ◽  
Transfer Rate ◽  
Reaction Rate ◽  
Hollow Fiber Membrane ◽  
Mass Transfer Rate ◽  
Fiber Membrane ◽  
Chemical Absorption ◽  
Physical Absorption ◽  
Membrane Contactors

To understand the mass transfer behaviors in hollow fiber membrane contactors, ozone fluxes affected by various conditions and membranes were investigated. For physical absorption, mass transfer rate increased with liquid velocity and the ozone concentration in the gas. Gas flow rate was little affected when the velocity was larger than the critical value, which was 6.1 × 10−3m/s in this study. For chemical absorption, the flux was determined by the reaction rate between ozone and the absorbent. Therefore, concentration, species, and pH affected the mass transfer process markedly. For different absorbents, the order of mass transfer rate was the same as the reaction rate constant, which was phenol, sodium nitrite, hydrogen peroxide, and oxalate. Five hydrophobic membranes with various properties were employed and the mass transfer behavior can be described by the Graetz–Lévèque equation for the physical absorption process. The results showed the process was controlled by liquid film and the gas phase conditions, and membrane properties did not affect the ozone flux. For the chemical absorption, gas film, membrane and liquid film affected the mass transfer together, and none of them were negligible.

scholarly journals Numerical Solution of Blood Flow and Mass Transport in an Elastic Tube with Multiple Stenoses

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Reima D. Alsemiry ◽  
Sarifuddin ◽  
Prashanta K. Mandal ◽  
Hamed M. Sayed ◽  
Norsarahaida Amin
Keyword(s):  
Mass Transfer ◽  
Blood Flow ◽  
Mass Transport ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Elastic Tube ◽  
Comprehensive Analysis ◽  
Flexible Wall ◽  
Inlet Conditions ◽  
Flow And Mass Transport

The simultaneous effect of flexible wall and multiple stenoses on the flow and mass transfer of blood is investigated through numerical computation and simulations. The solution is obtained using the Marker and Cell technique on an axisymmetric model of Newtonian blood flow. The results compare favorably with physical observations where the pulsatile boundary condition and double stenoses result in a higher pressure drop across the stenoses. The streamlines, the iso-concentration lines, the Sherwood number, and the mass concentration variations along the entire wall segment provide a comprehensive analysis of the mass transport characteristics. The double stenoses and pulsatile inlet conditions increase the number of recirculation regions and effect a higher mass transfer rate at the throat, whereby more mass is expected to accumulate and cause further stenosis.

Free Convective Mass Transfer at Isosceles Triangular Surfaces of Varying Inclination

2003 ◽  
Vol 68 (11) ◽  
pp. 2080-2092 ◽  
Author(s):  
Martin Keppert ◽  
Josef Krýsa ◽  
Anthony A. Wragg
Keyword(s):  
Mass Transfer ◽  
Transfer Rate ◽  
Mass Transfer Rate ◽  
Mass Transfer Process ◽  
Sulfate Solution ◽  
Convective Mass Transfer ◽  
Varying Length ◽  
Inclined Surface ◽  
Vertical Case ◽  
Limiting Diffusion Current

The limiting diffusion current technique was used for investigation of free convective mass transfer at down-pointing up-facing isosceles triangular surfaces of varying length and inclination. As the mass transfer process, copper deposition from acidified copper(II) sulfate solution was used. It was found that the mass transfer rate increases with inclination from the vertical to the horizontal position and decreases with length of inclined surface. Correlation equations for 7 angles from 0 to 90° were found. The exponent in the ShL-RaL correlation ranged from 0.247 for the vertical case, indicating laminar flow, to 0.32 for inclinations of 60 to 90°, indicating mixed or turbulent flow. The general correlation ShL = 0.358(RaL sin θ)0.30 for the RaL sin θ range from 7 × 106 to 2 × 1011 and inclination range from 15 to 90° was obtained.

Distributed mass transfer rate for modelling the leaching of porous granular materials containing soluble pollutants

2000 ◽  
Vol 55 (7) ◽  
pp. 1257-1267 ◽  
Author(s):  
Tiruta-Barna Ligia ◽  
Barna Radu ◽  
Moszkowicz Pierre ◽  
Bae Hae-Ryong
Keyword(s):  
Mass Transfer ◽  
Granular Materials ◽  
Transfer Rate ◽  
Mass Transfer Rate

Enhancement of formic acid production from CO2 in formate dehydrogenase reaction using nanoparticles

RSC Advances ◽  
2016 ◽  
Vol 6 (111) ◽  
pp. 109978-109982 ◽  
Author(s):  
Young-Kee Kim ◽  
Sung-Yeob Lee ◽  
Byung-Keun Oh
Keyword(s):  
Mass Transfer ◽  
Formic Acid ◽  
Acid Production ◽  
Transfer Rate ◽  
Formate Dehydrogenase ◽  
Mass Transfer Rate ◽  
Liquid Mass ◽  
Dehydrogenase Reaction ◽  
Liquid Mass Transfer ◽  
Mesoporous Nanoparticles

In an enzyme process using a gas substrate, the enhanced gas liquid mass transfer rate of the gas substrate by methyl-functionalized mesoporous nanoparticles could improve the productivity.

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