Mass transfer from a solid soluble sphere to a flowing liquid stream

Abstract

Abstract Solution rates of 1/2‐, 3/4‐, and 1‐in. cast benzoic acid spheres were measured under natural‐and forced‐convection conditions. Upward‐flowing streams of water and aqueous propylene glycol, in laminar and turbulent flow, were used to contact single spheres in either a 1.50‐ or 4.00‐in.‐ diameter column. Sphere Reynolds numbers ranged from 10 to 16,920; Schmidt numbers from 987 to 69,680; sphere‐ to column‐diameter ratios, d s /d c , from 0.123 to 0.497; and Grashof numbers from 5,130 to 125,200. The Sherwood number was found independent of the laminar‐turbulent transition for pipe flow and the sphere‐ to column‐diameter ratio when the Reynolds number is based on the average fluid velocity and sphere diameter. A correlation of the data based on the additivity of the natural and forced convection processes is proposed, and statistical analyses of the new experimental data result in equations which correlate other heat and mass transfer data for single spheres immersed in bounded and free‐jet streams of gases and liquids for N Re, S from 1 to 30,000 and N Se from 0.6 to 3,000, within an average deviation of about 20%.