Current density profiles at thin layer electrochemical cells under laminar and turbulent regimes

• Published in: Electrochimica acta Vol. 467; p. 143030
• Main Author: Zinola, Carlos F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.11.2023
• Subjects: Boundary layers; Current density; Linear momentum; Turbulence; Turbulence; Linear momentum; Current density; Boundary layers
• ISSN: 0013-4686
• DOI: 10.1016/j.electacta.2023.143030

•Resolution of linear momentum was completed by Dirichlet and Neumann boundary conditions.•Asymptotic tangential and normal velocities reduced to Blasius’ solutions.•Analytical functions for velocity, concentration and current density were obtained at laminar and turbulent flows.•Experimental results for ferrocyanide ion and dissolved hydrogen oxidations were compared with the predicted theory. The transition of laminar to turbulent regimes on smooth electrocatalysts in thin-film electrochemical cells is a subject of study with the aim of predicting current density profiles. Analytical solutions are obtained for velocity profiles under steady state conditions for both hydrodynamic conditions applying a proper velocity contour condition on the catalyst surface. This state is necessary to describe electrochemical cell performances since in these cases, electrode reactions occur at the surface and not in the bulk of the electrolyte. The obtained equations for linear momentum under asymptotic conditions reduce to the solutions obtained by classical Power Series methods years ago. Concentration and current density profiles are also solved accordingly and compared with experimental data of fast redox and dissolved gas reactions on smooth noble metal electrocatalysts. Velocity profiles at laminar to turbulent flow transition regimes (blue solid lines). Evolution of the boundary layer (violet lines) along the vertical electrochemical cell. Predicted theory (continuous lines) for the normalised current density, j(X)/jo, vs. dimensionless length, X, for ferrocyanide ion oxidation at 0.12 V under 0.005 (red), 0.016 (green), 0.12 (grey) and 0.92 (blue) cm s−1 velocities. [Display omitted]