The Role of Natural Convection in Electrolytic Processes

It is shown both theoretically and experimentally that at a vertical electrode a well‐defined convective flow due to the generally smaller density in the boundary layer and the resulting buoyancy force exists, analogous to natural convection in the case of heat transfer from a radiator to ambient air. The interplay between diffusion and convective flow determines the limiting current density which occurs if such a voltage is applied that the concentration of one of the reactants at the electrode drops to zero. Observed values of the limiting current density in a solution of copper sulfate and sulfuric acid are close to calculated values.