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Electrochemical measurement of velocity gradient at the wall of a helical tube

✍ Scribed by Sylvain Galier; Sébastien Issanchou; Philippe Moulin; Michael J. Clifton; Philippe Aptel

Publisher
American Institute of Chemical Engineers
Year
2003
Tongue
English
Weight
575 KB
Volume
49
Category
Article
ISSN
0001-1541

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✦ Synopsis

Abstract

An electrochemical technique was used for measuring the wall velocity gradient in two coiled pipes: a torus and a helix. An electrochemical oxidation reaction was employed with its rate limited by mass transfer. Measurement of the diffusion‐limited current at a microelectrode embedded flush with the wall allows the wall shear rate to be determined. The flow velocity was varied through both the laminar and turbulent regimes. Measurements were made for different electrode positions on the pipe circumference and, as expected, the highest shear rate was found at the outside of the curve, with the lowest value at the inside. In the case of the helical pipe, maxima and minima in shear rate were shifted slightly away from the positions observed for the torus.

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