Flow and Transport Due to Natural Convection in an Electrolytic Cell: II. Experimental Measurements of Velocity and Cell Potentials, and Comparison with the Mathematical Model

Abstract

A zinc-air cell wherein the zinc was present as a bed of particles and the electrolyte circulated by concentration driven natural convection is described. The circulation was from top to bottom within the bed with return channels on either side of the bed. Velocity measurements were made in the channels by laser-Doppler velocimetry and reached a peak of up to 0.9 mm/s (corresponding to a superficial velocity of about 38 gm/s in the bed) early in a constant current discharge. Velocities were satisfactorily predicted by the mathematical model described in Part I. The potential drop across the anode chamber was measured and showed fair agreement with the mathematical model. The model was used to make predictions concerning changes in cell design or operation.) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 132.239.1.231 Downloaded on 2015-06-04 to IP

Flow and Transport Due to Natural Convection in a Galvanic Cell: I. Development of a Mathematical Model

“…The equation to be solved, Eq. 1, was of the form i,=Oatx=L [9] i2= -iatx=0 [10] aC a'C aC -=D---u +G [17] at ay' 'ay 4,=Oatx=0 [11] Equations 8-10 expressed the facts that the current was The equation was differentiated with respect to time and carried entirely by the electrolyte at x = 0 and entirely by the order of differentiation reversed on the right to obtain the metal phase at x = L. Equation 11 served to define the reference potential as that of the electrolyte at the 3C a' ac a (aC'1 [18] diaphragm.…”