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Details for article 10 of 11 found articles
| Title: |
POLAROGRAPHIC DETERMINATION OF MASS TRANSFER IN A STAGNATION FLOW |
| Author: |
Firouztale, E. Stein, J.E. Ultman, J.S. |
| Appeared in: |
Chemical engineering communications |
| Paging: | Volume 22 (1983) nr. 1-2 pages 11-19 |
| Year: |
1983-07-01 |
| Contents: |
An electrochemical technique, oxygen polarography, was used to characterize the mass transfer coefficient for diffusion of oxygen to the surface of a circular cathode in a stagnation flow; because the electrical current output depended upon the magnitude of the impinging velocity, this method could form the basis of an electrochemical velocity probe. Four cathode assemblies consisted of 1.28 cm diameter/2.54 cm long polymethylmethacrylate rods with a circular cathode of diameter 1.28 cm, 0.64 cm, 0.32 cm or 0.13 cm vacuum deposited on their flat surface. Each cathode assembly was placed in a 2.54 cm diameter flow loop such that a fully-developed flow (8000 ≥ Reynolds number ≥ 200) of aerated saline solution impinged upon the cathode surface The effect of radial position on electrical current output was studied by placing the cathode assemblies at the center of the tube, halfway between the centerline and the wall, and at the tube wall. For the two largest cathodes, the output currents decreased as the cathode assembly was moved to the wall. The smallest cathode exhibited the opposite trend. The output correct of the cathode of intermediate diameter, 0.16 cm, was virtually unaffected by the radial position. Mass transfer coefficient (KL) values were computed at the centerline position and a power law relationship with mean axial tube velocity (u) was postulated: kL = γun, where γ and n are positive parameters. The regressed values of γ and n were 1.11 × 103 (cm7sol;s)0.5 and 0.502, respectively, during laminar flow and 1.14 × 10-3 (cm/s)0.6 and 0.391, respectively, for the turbulent regime. The final regressed value of n in the laminar regime was essentially the same as the theoretical value of 0.5. |
| Publisher: |
Taylor & Francis |
| Source file: |
Elektronische Wetenschappelijke Tijdschriften |
Details for article 10 of 11 found articles
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