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Journal of Applied Electrochemistry

, Volume 39, Issue 9, pp 1437–1442 | Cite as

Effect of a net on the limiting current distribution in a parallel plate electrochemical reactor. Part II: combined effects

  • Murali Venkatraman
  • J. W. Van Zee
Original Paper

Abstract

In Part I, we used computational fluid dynamics (CFD) to solve the Navier-Stokes equations surrounding the inert net in a parallel plate channel and presented the individual effects of the transverse and longitudinal ribs on the limiting current density distribution. The type, location, spacing, and number of the ribs of the net were shown to affect the local and average current density distributions on each of the two electrodes. In Part II, we present the combined effects of the longitudinal and transverse ribs on the limiting current distribution. We calculated the enhancement factors for both the combined and individual effects and compared. The longitudinal ribs decreased the average current density whereas the transverse ribs increased the average current density relative to the no-net parallel plate reactor system. A maximum enhancement of 250% in the average current density for a spacing of 0.94 × 10−3 m was obtained with 16 transverse ribs. For the same spacing, a negative 70% enhancement was obtained with 14 longitudinal ribs and no transverse ribs. A maximum enhancement of 180% was observed for the entire net (14 longitudinal and 29 transverse ribs). The enhancements at each electrode are different for a given geometry.

Keywords

Enhancement factor Limiting current Longitudinal and transverse ribs Nusselt number distribution Obstructed channel flow 

List of symbols

h1

Thickness of transverse rib in z direction (m)

h2

Thickness of longitudinal rib in z direction (m)

i

Local current density (A m−2)

iavg

Plate-average current density (A m−2)

iavg-noribs

Plate-average current density for no-ribs case(A m−2)

i*

Normalized local current density (dimensionless)

L

Electrode length in y direction (m)

W

Electrode width in x direction (m)

w1

Width of the longitudinal rib in x direction (m)

w2

Width of the transverse rib in y direction (m)

Greek symbols

Deviation factor (dimensionless)

η

Non-dimensional x coordinate

ζ

Non-dimensional y coordinate

λ

Enhancement factor [dimensionless Equation (1)]

Subscripts

1

Electrode 1

2

Electrode 2

avg

Average

avg_noribs

Average for the no-ribs case

Superscripts

*

Dimensionless quantity obtained by dividing respective quantity by its average

Notes

Acknowledgement

The authors acknowledge Dr. Sirivatch Shimpalee of University of South Carolina, for his useful inputs in the CFD calculations.

References

  1. 1.
    Venkatraman M, Van Zee JW (2009) Effect of a net on the limiting current distribution in a parallel plate electrochemical reactor: part I. individual effects. J. Appl. Electrochem. doi: 10.1007/s10800-009-9819-0
  2. 2.
    Venkatraman M (2006) Models for mass transfer effects in semi-fuel cells and for a Silver–Zinc battery. Dissertation, University of South Carolina, ColumbiaGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.Department of Chemical EngineeringUniversity of South CarolinaColumbiaUSA
  2. 2.CSIRO Materials Science and EngineeringClayton South MDCAustralia

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