Numerical Simulation of Ionic Mass-Transfer Rates with Natural Convection in CuSO4 – H2SO4 Solution: II. Comparisons Between Numerical Calculations and Optical Measurements

Abstract

A mathematical model is developed in Part I of this study for the ionic mass-transfer rates associated with natural convection developing along both electrodes immersed in a aqueous electrolyte. The additional effect of an excess amount of is discussed through the comparisons with the optical measurements. The concentration profiles of both and ions and the natural convective velocity profile have been measured by a two-wavelength holographic interferometer and the tracer method. The present calculation quantitatively agrees with the measured ionic mass-transfer rates toward the electrode surface except for copper electrolysis in an unsupported electrolyte above one-half of the limiting current density. The optical observation suggests that a substantially steady state is attained within 180 s after starting the electrolysis in every case. The numerical calculation predicts a further development of ionic mass-transfer phenomena over 600 s. It is closely related to both secondary flow and electrolyte stratification phenomena.