The mirage effect with a supporting electrolyte at constant mass transfer through the diffusion layer

1994 ◽  
Vol 365 (1-2) ◽  
pp. 165-169 ◽  
Author(s):  
J.M. Rosolen ◽  
M. Fracastoro-Decker ◽  
F. Decker
Keyword(s):  
Mass Transfer ◽  
Diffusion Layer ◽  
Supporting Electrolyte ◽  
Constant Mass ◽  
Mirage Effect

Effects of Schmidt Number on Turbulent Mass Transfer Around a Rotating Circular Cylinder

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Dong-Hyeog Yoon ◽  
Kyung-Soo Yang ◽  
Klaus Bremhorst
Keyword(s):  
Mass Transfer ◽  
Circular Cylinder ◽  
Diffusion Layer ◽  
Time Scale ◽  
Schmidt Number ◽  
Concentration Field ◽  
Limiting Behavior ◽  
Rotating Circular Cylinder ◽  
Scale Ratio ◽  
Turbulent Mass Transfer

Characteristics of turbulent mass transfer around a rotating circular cylinder have been investigated by Direct Numerical Simulation. The concentration field was computed for three different cases of Schmidt number, Sc = 1, 10 and 100 at ReR* = 336. Our results confirm that the thickness of the Nernst diffusion layer decreases as Sc increases. Wall-limiting behavior within the diffusion layer was examined and compared with that of channel flow. Concentration fluctuation time scale was found to scale with r+2, while the time scale ratio nearly equals the Schmidt number throughout the diffusion layer. Scalar modeling closure constants based on gradient diffusion models were found to vary considerably within the diffusion layer. Results of an octant analysis show the significant role played by the ejection and sweep events just as is found for flat plate, channel, and pipe flow boundary layers. Turbulence budgets revealed a strong Sc dependence of turbulent scalar transport.

scholarly journals Mass Transfer Analysis in PEFC Diffusion Layer by Lattice Gas Automata Method

2006 ◽  
Vol 49 (3) ◽  
pp. 653-659 ◽  
Author(s):  
Takashi YOSHIMOTO ◽  
Yosuke MATSUKUMA ◽  
Gen INOUE ◽  
Masaki MINEMOTO
Keyword(s):  
Mass Transfer ◽  
Diffusion Layer ◽  
Lattice Gas ◽  
Lattice Gas Automata

Electrochemical Removal of Copper and Lead from Industrial Wastewater: Mass Transport Enhancement

2009 ◽  
Vol 44 (2) ◽  
pp. 183-188 ◽  
Author(s):  
Asim Yaqub ◽  
Huma Ajab ◽  
Saqib Khan ◽  
Sajjad Khan ◽  
Robina Farooq
Keyword(s):  
Mass Transfer ◽  
Energy Consumption ◽  
Mass Transport ◽  
Diffusion Layer ◽  
Industrial Wastewater ◽  
Lead Nitrate ◽  
Electrochemical Treatment ◽  
Bulk Solution ◽  
Metallic Ions ◽  
Mass Transport Process

Abstract The effects of ultrasonic frequencies on both the mass transport process and diffusion layer were investigated during electrochemical treatment. The rates of mass transfer at a stainless steel cathode were measured for copper and lead in dilute acidified copper sulphate and lead nitrate solutions at different ultrasonic frequencies. Concentrations in bulk solution were determined by atomic absorption spectrophotometer. By increasing frequencies from 40 to 100 kHz, a high value for the mass transfer coefficient and an effective thinning of the diffusion layer were observed. Higher rates of mass transfer reduced energy consumption. Use of ultrasound with electrochemical processes can provide valuable contributions to remove metallic ions from industrial wastewater without using extra chemicals. The process has efficiently reduced the cost of energy consumption and deposition time.

scholarly journals Mass Transfer Analysis in PEFC Diffusion Layer by Lattice Gas Automata Method

2005 ◽  
Vol 71 (711) ◽  
pp. 2642-2648
Author(s):  
Takashi YOSHIMOTO ◽  
Yosuke MATSUKUMA ◽  
Gen INOUE ◽  
Masaki MINEMOTO
Keyword(s):  
Mass Transfer ◽  
Diffusion Layer ◽  
Lattice Gas ◽  
Lattice Gas Automata

Diffusion-Layer Theory for Flows Under Apparent Wall Slip

1998 ◽  
Vol 63 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Ondřej Wein
Keyword(s):  
Mass Transfer ◽  
Velocity Profile ◽  
Solid Surface ◽  
Diffusion Layer ◽  
Analytical Formula ◽  
Wall Slip ◽  
Slip Effect ◽  
Local Power ◽  
Overall Mass Transfer Coefficient ◽  
Apparent Wall Slip

An explicit analytical formula is given for the overall mass transfer coefficient between the bulk of flowing microdisperse liquid and a small but finite active part of a solid surface. The apparent wall slip effect inside a diffusion layer is reflected through the local power-law velocity profile, vx(z) = Bzp, and a distribution B = B(x,y) over the solid surface.

Organic Sonoelectrochemistry on Mercury Pool Electrode

2000 ◽  
Vol 65 (6) ◽  
pp. 941-953 ◽  
Author(s):  
Jiří Klíma ◽  
Jiří Ludvík
Keyword(s):  
Mass Transfer ◽  
Layer Thickness ◽  
Diffusion Layer ◽  
Current Density ◽  
Electrode Surface ◽  
Diffusion Layer Thickness ◽  
Local Mass Transfer ◽  
Electrolytic Current ◽  
Mercury Electrodes ◽  
Instantaneous Increase

So far, the influence of sonication on the electrolytic current was studied only at solid or rather miniaturized mercury electrodes. The presented paper reports on sonoelectrochemical experiments at a liquid mercury pool electrode. Two sonoelectrochemical cells have been developed and tested. It was shown that during sonication, the electrolytic current increases in a number of individual peaks representing short local enhancements of current density due to vigorous local mass transfer and instantaneous increase of fresh electrode surface. Both these effects are caused by microjets of solution formed during violent unsymmetric collapses of cavitation bubbles in the close vicinity of the electrode surface. The newly formed electrode surface and the decrease in the diffusion layer thickness were estimated and discussed. An example is presented where the sonication is used for destruction of a film of products formed during electrolysis of cysteine, that otherwise rapidly inhibits continuation of the electrode process.

Absorption Process in MgCl2–NH3 Thermochemical Batteries With Constant Mass Flow Rate

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Seyyed Ali Hedayat Mofidi ◽  
Kent S. Udell
Keyword(s):  
Mass Transfer ◽  
Mass Flow Rate ◽  
Reaction Zone ◽  
Mass Flow ◽  
Flow Rate ◽  
Absorption Rate ◽  
Constant Mass ◽  
Absorption Process ◽  
Cell Reactor ◽  
Series Of Experiments

In this paper, the performance of a thermochemical battery based on magnesium chloride and ammonia pair with a constant mass flow rate of ammonia gas is studied through a series of experiments using single and multicell configurations. It is shown that a lower mass flow rate lowers the temperature of the reactive complex and increases the duration of the absorption process. However, it was observed that the reaction eventually becomes mass transfer limited which slows the absorption rate to values below those specified by the mass flow controller (MFC). It was shown in the single-cell reactor that a reaction zone starts at the inlet and moves toward the end of the reactor. The mass transfer limited reaction zone movement reduces the absorption rate and temperature in the reaction zone. The overall performance of a multicell thermal battery is also studied to analyze behavior of such reactors as well. It was shown that the controlling the flow rate of ammonia can cause the cells to deviate in absorption rate.

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