Mass Transfer to a Rotating Disk

Experimental rates are reported for oxygen mass transfer to a disk rotating in 3½% (0.6M) aqueous . Average Sherwood numbers, , were obtained over a range of temperatures from 0.6°C (33°F) to 100°C (212°F), a range of Reynolds numbers, , from , and a range of Schmidt numbers, , from 34 to 1400. The laminar flow results agree with generally accepted theories such as the Newman extension of the Levich theory, Sparrow and Gregg, and Gregory and Riddiford. Transition from laminar to turbulent flow was found to occur at . A least squares analysis indicates that the turbulent flow results for and can be correlated by

with a standard error of the estimate of ± 8.9%. For , Eq. (I) requires modification because there are significant contributions (over 10%) to the average Sherwood number due to laminar flow in the center. The experimental average Sherwood numbers agree well with friction analogy theories using either the Tien, Wasan, and Wilke or the Deissler eddy diffusivity profiles.