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.