The concentration and the velocity fields in a small copper refining cell with plane vertical electrodes were studied experimentally. The electrolyte was an aqueous solution of 0.3 M CuSO4 with 1.0 M H2SO4 as a supporting electrolyte. The electrolysis was done under galvanostatic conditions. The development in time of the concentration and velocity fields was measured for different values of the current density. The concentration field was measured by Holographic Laser Interferometry (HLI) and the velocity field by Laser Doppler Velocimetry (LDV). Experimental results were compared with numerically obtained concentration and velocity profiles based on a mathematical model developed earlier. The agreement was found to be good.

Free convection and stratification of the electrolyte in a lead-acid cell with porous electrodes and during recharge were studied theoretically and experimentally. The concentration field was measured by means of Holographic Laser Interferometry (HLI) and the velocity field by means of Laser Doppler Velocimetry (LDV). A two-dimensional mathematical model was also developed for mass transfer and electrolyte motion during the process. It was assumed for simplicity that the electric current density and porosities of the electrodes were constant and uniformly distributed in the electrodes. The results from the experiments were compared with numerical results obtained from the mathematical model. The agreement was found to be good. A simplified mathematical model, as an alternative to the full numerical problem, was also developed. The results of the simplified model proposed here proved to be in good agreement with the results from the full numerical solution, albeit for sufficiently large times.