INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, cilt.48, sa.3, ss.1593-1602, 2009 (SCI-Expanded)
The local mass transfer coefficients between an impinging swirl jet flow and a flat circular surface in a cylindrical cell were measured by the electrochemical limiting diffusion current technique. Helical-type swirl generators were used to generate swirl flow with intensities in the range of S = 0-0.73. The experiments were carried out for a jet Reynolds number range of 10 950-43 800, a nozzle-to-surface distance range of 2-10, and a dimensionless radial distance range of 0-15. The measured local mass transfer distributions in the radial direction exhibited an increase first and then a decrease and a converging behavior as the radial distance increased. It was observed that increasing Reynolds number increased the mass transfer rate, but its effect was reduced with an increase in swirl intensity. Increasing swirl intensity decreased transfer coefficients but increased their uniformity over the disk surface. The change in the nozzle-to-surface distance affected mass transfer coefficients up to a dimensionless radial distance of approximately r/d(j) < 8, and beyond this distance, they converged in almost one line, showing no effect of this parameter. Mass transfer correlations for Sherwood numbers whose average was taken over the surface and for Sherwood numbers at the stagnation point were developed as a function of the experimental parameters.