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A diffusion model for rinsing
Author(s) -
Tallmadge John A.,
Buffham Bryan A.,
Barbolini Robert R.
Publication year - 1962
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690080517
Subject(s) - thermal diffusivity , diffusion , chemistry , mass diffusivity , thermodynamics , mass transfer , convection , diffusion equation , mechanics , analytical chemistry (journal) , chromatography , physics , economy , economics , service (business)
The removal, by immersion in water, of solute from a solution adhering to a 14.7‐cm. wide flat plate has been experimentally investigated at about 80°F. over a 3.5 to 1,000 sec. range of contact time. Diffusivity was varied over a sixfold range (from 0.5 to 3.0 by 10 −5 sq.cm./sec.) by the use of two dilute solutions, pontamine blue dye and 0.09 N nitric acid. Equations relating the effects of film thickness, contact time, and diffusivity on the mass fraction of solute which was not removed during rinsing were developed from a diffusion model, under the assumption that the adhering solution was present throughout as a stagnant film of uniform thickness. The experimentally determined effects of time and diffusivity agreed with those indicated by the idealized model. The agreement of these effects and the magnitude of unremoved solute gave strong indication that diffusion may be considered the controlling mechanism. The experimental dip and rinse method used offers potential as a technique for studying natural convection at transient conditions in the region where diffusion is also important, because it offers the advantage of allowing independent selection of initial fluid densities.