H. Sarac et al., NATURAL-CONVECTION MASS-TRANSFER AT A HORIZONTAL CYLINDER ELECTRODE WITH AN OPPOSED THERMAL BUOYANCY EFFECT, Electrochimica acta, 38(17), 1993, pp. 2589-2598
Simultaneous heat and mass transfer at horizontal cylinder electrodes
in free convection has been investigated experimentally using the elec
trochemical limiting diffusion current technique, in the situation whe
re the concentration and thermal buoyancy effects are opposed. The fer
ri-ferrocyanide redox system was used for the mass transfer measuremen
ts, the electrolyte system being equimolar potassium ferri-ferrocyanid
e with 0.5 M NaOH as supporting electrolyte. The chosen concentrations
were 0.01, 0.02, 0.05, 0.10 and 0.2M. Two different nickel cylinders
of diameter of 33.2 and 21.3mm were used, each 100mm in length. The su
rface temperature of the cylinder varied from 20%C (isothermal) to 85%
C. Results for the opposed upward and downward convection were correla
ted using a combined Grashof number for mass transfer in the range 10(
8)<GR(m)Sc<10(11). The Schlieren technique of Bow visualisation was us
ed for observation of the flow structure.