Mass transfer characteristics of corrugated surfaces

The mass transfer characteristics of flat and corrugated electrode surfaces in an electrochemical cell are described. The effect of the distance between the surfaces (electrode to electrode separation) on the mass transport was investigated and empirical correlations are presented. Mass transfer coefficients were determined using the limiting current technique, for the reduction of potassium ferricyanide ion in excess of potassium carbonate. Mass transfer measurements were carried out for a Reynolds number range of 125–3500 and an equivalent diameter range of 2.6–8.6 mm, at a temperature of 20 °C and a Schmidt number of 1469. The data showed that corrugated surfaces enhanced the solid to liquid mass transfer rates, to the extent that characteristics of a turbulent regime were obtained. The smaller inter-electrode gap produced the higher mass transfer rates. Enhancements in mass transfer of up to 30 fold were achieved by using a corrugated surface in place of a flat surface, due to the frequent disruption of the boundary layer imposed by the corrugated design. Through the analogy between heat transfer and mass transfer the data indicates the expected enhancement to be gained for heat transfer to corrugated heat exchanger surfaces with the type of flow studied.