This work was undertaken to clarify the mechanism of mass transfer into a liquid film flowing over the surface of a sphere and to see whether liquid is mixed completely or not at the points of juncture between the spheres connected in a vertical row. Experiments were performed on the absorption of pure carbon dioxide by water with and without a wetting agent, in columns containing 1, 3 and 5 spheres, respectively.
Experimental data for single sphere are shown in Figs. 3 and 4, and those for multiple sphere in Fig. 6, as the plot of the HL values against the Reynolds number on logarithmic coordinates. Results with single sphere were in good agreement with the theoretical equation based on the assumptions of unsteady-state diffusion and parabolic velocity distribution in the liquid film, as shown in Fig. 5. The addition of a wetting agent caused no change in the absorption rate in the case of single sphere, and the HL values for both the runs with and without agent were the same.
Fig. 7 shows the correlation among the results obtained with multiple sphere, when pure water was used as a solvent. Good agreement was obtained between the data and the theoretical equation, derived from the assumption that the mixing of the liquid was complete at the points of juncture between the spheres. Fig. 8 shows a similar plot of the data obtained by Yoshida and Koyanagi.⁷⁾
When a wetting agent was added to water, the values of HL were higher than those for pure water and increased with the number of spheres, as shown in Fig. 9. The data obtained by authors and those by Lynn, Straatemeier and Kramers⁵⁾ were in fairly good agreement with the theoretical equation based on the assumption that there was no mixing of the liquid as it flew from one sphere to the next.