Mass transfer from a soluble solid sphere

Abstract

Abstract Mass transfer from 3/8‐ and 1/2‐in.–diameter spheres of adipic acid and from 3/8‐, 1/2‐, 5/8‐ and 3/4‐in.‐diameter spheres of benzoic acid into a controlled stream of water passing in laminar flow through a 3‐in.‐diameter pipe is found to be correlated by the single equaton N Sh = 2 + 0.95 N Re 0.5 N Sc 0.33 for sphere Reynolds numbers between 100 and 700. The limitations on the application of this equation, due to mass transfer by natural convection, are discussed. Correlations are also obtained for transfer from separate regions of the sphere surface. Skin–friction‐drag coefficients for single fixed spheres have been calculated from reported pressure distributions for Reynolds numbers between 100 and 1,000. Good agreement is obtained between the mass transfer j factor and other reported values for heat transfer, but comparison with the calculated frictional forces indicates that the equality proposed by Colburn ( 3 ) does not hold, because the distributions of the mass transfer and the skin friction over the surface differ.