Numerical Simulation of Hydrodynamic and Mass-Transport Properties at a Laminar Rotating Cylinder Electrode

Abstract

The rotating cylinder electrode (RCE) configuration is one of the most used electrochemical configurations for turbulent flow regimes. For laminar regimes, it appears problematic to choose the adapted predictive correlation for limiting current density. This is essentially due to the difficulty of choosing the characteristic length and dimensionless number (Reynolds, Taylor,…) in this geometrical configuration, mainly due to its two-dimensional character, whereas the rotating disk cylinder is well approximated with the monodimensional assumption. This two-dimensional character makes inaccurate the use of mean correlations because factors like electrode position and length are usually not correlated. The present work shows that in the case of the RCE configuration, the computational fluid dynamic calculation appears to be an adapted tool to access to the electrode vicinity hydrodynamic and mass-transport properties. A design methodology has been used to correlate laminar fluid flow properties with classical factors: kinetic viscosity, rotation velocity, and inner electrode diameter. The flow properties are correlated and lead to the mean wall shear stress at the electrode and then to the average current density at the electrode, which are original correlations under diffusion-limited assumptions. The present work uses published empirical correlations as experimental validation data.

Numerical Simulation of a Batch Rotating Cylinder Electrode System for Bulk Electrolysis

“…The obtained k m is 1.26 × 10 −5 m/s for the cell with d S = 5 cm, with the same order of magnitude from Mizushina's correlation: 15,22 Sh = 0.74Ta 0.50 Sc 0.33 [15] where Ta is Taylor number composed of the density and viscosity of electrolyte, rotation speed (ω), annular gap distance (d E ) and rotor radius (r E ):…”

“…Considering the practical operation in most of industrial applications, we selected a low rotation speed (100 rpm) to simulate the process, so the laminar flow can be expected. Similar assumptions were used in the research of Mandin et al 15 Therefore, basic equation of continuity and equation of motion (Navier-Stokes equation) in a cylindrical coordinate are employed:…”

“…Meanwhile, another type of work by direct numerical simulation of transport equations was also in progress. [15][16][17][18] The results from direct numerical simulation could provide the message of potential, current and concentration distributions in an RCE system, so-called tertiary current distribution. This type of simulation results also shows good accordance with the experiments.…”

Simulation studies on a rotating ring disk electrode system: Role of supporting electrolyte in determination of relevance of ionic migration

“…Electrochemical parameters are frequently determined by fitting data to theoretical curves similar to those presented here. This work clearly shows that neglect of migration in the theoretical analysis in systems involving appreciable migration can lead to considerable error in estimation of the parameters.…”

Hydrodynamic Modeling of Copper Electrodeposition at a Vertical Rotating Cylinder Electrode

“…Here, the voltammetry data reported below are re-interpreted by solving these equations to infer the diffusion coefficient of cupric ions at 45 o C. The diffusion coefficient at 65 o C was taken from Dutra et al (16) as described previously (11)(12)(13)(14) and in Table I. Figure 3 shows voltammograms for 45oC and 65oC with the RCE rotating at 10 and 25 rpm.…”