Computation of primary current distribution and cell resistance at model electrodes with circular perforations

Abstract

A model of a gas-evolving production-type cell with a circularly perforated anode is described. A unit of the model was composed of a disk cathode, a separator and a ring anode in turn. These were located in a cylindrical cell filled with solution. Primary current and potential distributions in the unit cell were computed by solving the Laplace equation in cylindrical coordinates by the finite element method. Geometric parameters determining the distributions were primarily the interelectrode distance and the percentage open area. Current distribution in the open part was larger than that in a rectangular cell with the same geometric parameters because of the cylindrically concentrated supply of the current from the inner part of the ring and the back side of the anode. The unit cell resistance was evaluated as a function of the geometric parameters. It exhibited a linear variation of the interelectrode distance and the square of the percentage open area. There was, however, a slight dependence of the percentage open area on the unit cell resistance and hence it is concluded that circularly perforated electrodes provide higher performance than louvre-type electrodes.