Convection in electrochemical systems.

Authors: Bark, F.H.
Document Type: Article
Pubstate: Published
Journal: Appl. Sci. Res.
Volume: 53   11-34
Year: 1994


Some theoretical and experimental results for the concentration and velocity fields that appear during unsteady electrolysis in small electrochemical cells are given. Two systems are considered: mod Cu mod CuSO/sub 4/(aq) mod Cu mod and mod PbO/sub 2/, PbSO/sub 4/ mod H/sub 2/SO/sub 4/(aq) mod Pb, PbSO/sub 4/ mod . For the former system, in which the electrodes are solid, both linear and nonlinear electrode kinetics are considered. For the more complicated latter system, where the electrodes are porous, attention is restricted to linear kinetics. Theoretical results are obtained by using both perturbation methods and numerical analysis. Experimental results are obtained by laser Doppler velocimetry and image laser holography. It is shown that the evolution of the concentration and velocity fields is controlled by stratification of the electrolyte. The boundary layer structure is similar to that appearing during nonlinear spin up of a homogeneous fluid. Theoretical and experimental results are in good agreement.