Al-Khateeb, M, Barker, R orcid.org/0000-0002-5106-6929, Neville, A orcid.org/0000-0002-6479-1871 et al. (1 more author) (2018) The effect of surface roughness on diffusion and chemical reaction controlled limiting currents on a Rotating Cylinder Electrode in deaerated solutions with and without CO2. Corrosion, 74 (9). pp. 971-983. ISSN 0010-9312
Abstract
The influence of surface roughness on mass transfer on a Rotating Cylinder Electrode apparatus is investigated experimentally for a roughness pattern consisting of grooves parallel to the direction of fluid flow. Mass transfer from four different samples, with roughness values of 0.5, 6, 20 and 34 μm, is measured using the limiting current technique for a range of rotational speeds in NaCl solutions saturated with N2 at pH=3 and 4. Comparison with available correlations for the Sherwood number in literature (which are independent of surface roughness and are either for specific or arbitrary roughness patterns) shows that H+ mass transfer only correlates well for particular levels of roughness and that their accuracy can be increased if a correlation is utilised which is a function of surface roughening. A new correlation for Sherwood number as a function of the Reynolds number, Schmidt number and surface roughness is proposed which agrees well with the mass transfer observed from all the rough surface cases considered for this particular roughness pattern. Complementary experiments in CO2 environments were used to assess the combined limiting current associated with H+ and H2CO3 reduction (with the latter occurring via the buffering effect and being associated with the slow CO2 hydration step). Although the increase in sample roughness clearly leads to an increase in the rate of H+ mass transfer, in the CO2 environments considered, surface roughness is found to have no significant influence on the limiting current contribution from H2CO3, which can therefore be determined from Vetter’s equation across this range of operating conditions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 NACE International. This is an author produced version of an article published in Corrosion. Uploaded in accordance with the publishers self archiving policy. |
Keywords: | Limiting current; Mass transfer; Surface Roughness |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Functional Surfaces (Leeds) The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Engineering Thermofluids, Surfaces & Interfaces (iETSI) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 07 Jun 2018 11:13 |
Last Modified: | 14 Aug 2018 09:29 |
Status: | Published |
Publisher: | NACE International |
Identification Number: | 10.5006/2552 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:131713 |