Convective Diffusion to a Rotating Disk

Abstract

Convective diffusion to a rotating-disk electrode is investigated. A coordinate transformation is employed that removes the discontinuous nature of the surface boundary conditions at the electrode-insulator edge and difficulties associated with the treatment of boundary conditions specified for infinite values of the radial and axial coordinates. The transformation also accounts for variations in the diffusion-layer thickness caused by changes in stir rates or fluid properties. For the transport-limited condition, the average current and the current distribution are functions of two dimensionless groups only: the Schmidt and Reynolds numbers. The current response is bounded by the Levich equation for large Schmidt and Reynolds numbers and by the well-known equation for the current response of a stationary disk in the limit of zero Schmidt or Reynolds numbers. Additional interfacial kinetic parameters are considered below the transport-limited condition.

Modelling and numerical simulation of hydrodynamical processes in a confined rotating electrode configuration

“…Many studies have appeared on the modelling and simulation of hydrodynamical processes in electrochemical cells . Different configurations have been investigated such as stationary or rotating disk electrodes [5][6][7][8][9][10][16][17][18]23,17,[25][26][27][28][29][30][31][35][36][37], ring-disk electrodes [13,17,18] line electrodes [32], paddle cells [33,34], rotating hemispheral electrodes (RHSE) [40,41], wall-jet electrodes [44], etc. We note that usually the authors consider monodimensional flux and that bidimensional full calculations have attracted less attention, mainly in relation to electromigration phenomena during electrolysis processes [15].…”

Re-examination of the diffusion–convection impedance for a uniformly accessible rotating disk. Computation and accuracy

“…Using Eqs. (24), (28) and (29), it is easy to prove that the low-frequency limit of the complex number Z k σ ( ) is equal to:…”

“…In contrast, Newman [22], Durbha and Orazem [23], Verbrugge [24] and Dong et al [25] investigated the influence of radial position on the disk electrode, at steady state, under 2-D mass transport conditions. Durbha et al [26] presented the mathematical formalism for frequencydomain techniques.…”

“…From the theoretical predictions in Refs. [22][23][24][25][26], it is known that current distribution on the electrode surface is highly uniform in the case of low Ohmic drop and slow electron-transfer kinetics. The present article focuses on such conditions and, therefore, on 1-D diffusion-convection processes.…”

The role of charge separation in the response of electrochemical systems

“…1993;Liu et al . 1993;Verbrugge 1995); fuel cells (Kinoshita & Stonehart 1977;Kinoshita 1982;Shimazu et al . 1988;Fedkiw & Her 1989;Mukerjee 1990;Srinivasan et al .…”