The Effect of an Impinging Fluid Jet on Mass Transfer and Current Distribution in a Circular Through-Hole

The effect of a single circular impinging fluid jet on hydrodynamic flow and mass transfer in a single through-hole centered at the stagnation point was investigated. Both submerged and unsubmerged jets were studied. Sectioned electrodes were used for direct experimental measurement of local rates of mass transfer and of hydrodynamic shear stress within individual through-holes. The ferricyanide system was used to obtain convective mass transfer rates upon controlled variation of jet Reynolds number, nozzle-to-workpiece distance, through-hole diameter, and aspect ratio. Data were used to establish mass-transfer correlations for both submerged and unsubmerged systems. It was found that the fluid flow in the through-hole corresponded to the hydrodynamic entrance region. A mathematical model of the current and potential distribution was used to identify dimensionless conditions for achieving uniform deposits and for insuring adequate convection rates.