TURBULENT HIGH SCHMIDT NUMBER ENTRANCE REGION MASS TRANSFER IN ANNULI

Entrance region and fully developed mass transfer from the inner core of annuli was investigated for a fully developed velocity profile and a Schmidt number of 760. Constant wall concentration was the satisfied boundary condition of the inner core. The ranges of parameters investigated were 21,400 to 75,600 for Reynolds number, 0.164 to 0.741 for the annulus diameter ratio, and 0.018 to 3.85 for the length to hydraulic diameter ratios. Experiments were performed in an open water flow loop. Mass transfer coefficients were obtained from weight loss measurements of benzoic acid life saver elements of various diameters and lengths. These elements were assembled as an integral part of the inner core of the annulus. Concentricity was maintained by a tensioning device. The local Sherwood number is found to be significantly affected by the annulus diameter ratio, Reynolds number, and the length to hydraulic diameter ratio. A correlation is developed which predicts 93% of the data used for its development to within ± 10%. Copyright © 1969 American Institute of Chemical Engineers