An Experimental Study of Nonuniform Current Distribution at Rotating Disk Electrodes

1970 ◽  
Vol 117 (8) ◽  
pp. 1044 ◽  
Author(s):  
Stanley Bruckenstein ◽  
Barry Miller
Keyword(s):  
Experimental Study ◽  
Current Distribution ◽  
Rotating Disk ◽  
Disk Electrodes

scholarly journals Molten Salt Electrometallurgy

2019 ◽  
Author(s):  
Charles Osarinmwian
Keyword(s):  
Molten Salt ◽  
Current Distribution ◽  
Scale Up ◽  
Rotating Disk ◽  
Comsol Multiphysics ◽  
X Ray ◽  
Disk Electrodes ◽  
Primary Current ◽  
Cell Construction ◽  
Primary Current Distribution

The experimental results are for electro-deoxidation in molten salt and the numerical results are for molten salt processes in electrometallurgy.<div>The internal cathode microstructure is analysed using SEM, Energy dispersive X-ray spectroscopy, and computerised X-ray tomography.<br></div><div>Numerical simulations using COMSOL multiphysics report results for molten salt processes using theory from rotating disk electrodes and multiphase flow. Scale-up of electro-deoxidation is discussed using primary current distribution simulations in various electro-deoxidation cell designs.<br></div><div>Experimental details of electro-deoxidation cell construction is referenced to and outlined in my earlier work: <i>Electrochim. Acta</i> <b>164</b>, 48 (2015)<br></div>

scholarly journals Molten Salt Electrometallurgy

2019 ◽  
Author(s):  
Charles Osarinmwian
Keyword(s):  
Molten Salt ◽  
Current Distribution ◽  
Scale Up ◽  
Rotating Disk ◽  
Comsol Multiphysics ◽  
X Ray ◽  
Disk Electrodes ◽  
Primary Current ◽  
Cell Construction ◽  
Primary Current Distribution

The experimental results are for electro-deoxidation in molten salt and the numerical results are for molten salt processes in electrometallurgy.<div>The internal cathode microstructure is analysed using SEM, Energy dispersive X-ray spectroscopy, and computerised X-ray tomography.<br></div><div>Numerical simulations using COMSOL multiphysics report results for molten salt processes using theory from rotating disk electrodes and multiphase flow. Scale-up of electro-deoxidation is discussed using primary current distribution simulations in various electro-deoxidation cell designs.<br></div><div>Experimental details of electro-deoxidation cell construction is referenced to and outlined in my earlier work: <i>Electrochim. Acta</i> <b>164</b>, 48 (2015)<br></div>

Mineral interfacial processes in the method of induced polarization

Geophysics ◽  
1984 ◽  
Vol 49 (7) ◽  
pp. 1105-1114 ◽  
Author(s):  
James D. Klein ◽  
Tom Biegler ◽  
M.D. Horne
Keyword(s):  
Frequency Domain ◽  
Diffusion Layer ◽  
Electrode Potential ◽  
Rotation Speed ◽  
Low Frequency ◽  
Rotating Disk ◽  
Active Species ◽  
Hydrodynamic Theory ◽  
Electrode Polarization ◽  
Disk Electrodes

A phenomenological laboratory investigation has been conducted of the IP response of pyrite, chalcopyrite, and chalcocite. The technique that was used is standard in electrochemistry and employs rotating disk electrodes. The effect of rotation is to stir the electrolyte and thus to restrict the maximum distance available for diffusion of electroactive aqueous species. For high rotation speed and low excitation frequencies, the mean diffusion length exceeds the thickness of the diffusion layer. The net effect is to reduce the electrode impedance at low frequency. The thickness of the diffusion layer and thus the impedance at low frequency can be controlled by the rotation speed. Measurements using rotating disk electrodes have been conducted in both the time domain and the frequency domain. For both pyrite and chalcopyrite, the results were the same: no dependence on rotation was observed. For frequency domain measurements with chalcocite, a strong dependence on rotation was observed. The interpreted diffusion layer thickness was found to depend on rotation speed to the [Formula: see text] power, in agreement with results predicted by hydrodynamic theory. The results of this study imply that there are two physical processes responsible for electrode polarization in the IP method. For chalcocite and perhaps other related copper sulfide minerals, the probable mechanism is diffusion of copper ions in the groundwater. In case, the phenomenon is correctly described by the Warburg impedance. Chalcocite’s distinctive response is thought to be related to its forming a reversible oxidation‐reduction couple with cupric ions in solution. No other common sulfide mineral forms a reversible couple with its cations in solution. For the other minerals of this study, the lack of dependence on rotation implies that diffusion of active species in the electrolyte is not the controlling process. Possible alternate mechanisms include surface controlled processes such as surface diffusion or adsorption phenomena. Ancillary data obtained during this study indicate the interface impedance of chalcopyrite is proportional to the electrode potential which in turn can be controlled by rotation speed, electrolyte composition, or application of an external dc current or voltage. This implies that the surface concentration of active species is dependent on electrode potential.

Jet Cooling at the Rim of a Rotating Disk

1979 ◽  
Vol 101 (1) ◽  
pp. 68-72 ◽  
Author(s):  
D. E. Metzger ◽  
W. J. Mathis ◽  
L. D. Grochowsky
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Jet Impingement ◽  
Rotating Disk ◽  
Impinging Jets ◽  
Turbine Engine ◽  
Transfer Rates ◽  
Jet Cooling ◽  
Geometric Conditions ◽  
Face Contour

Results are presented from an experimental study conducted to measure heat transfer rates at the rim of a rotating disk convectively cooled by impinging jets. The disk face contour radially inward from the rim is varied to simulate the geometric conditions found on gas turbine engine rotors. Heat transfer rates are found to be relatively unaffected by impingement for jet flowrates less than the order of one-tenth the disk pumping flow. Disk pumping flows are evaluated through the use of an analysis which accounts for the presence of the disk hub. At larger jet flowrates, heat transfer rates increase strongly with increasing jet flow, reaching two to three times the no-impingement values at jet flowrates approximately equal to the pumped flow. All the heat transfer results, both with and without jet impingement, are essentially unaffected by changes in the disk face contour.

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