ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Mass transfer rates in laminar and turbulent nonseparated boundary layers are asymptotically expanded for small values of the diffusivity DAB, with a uniform state on the mass transfer surface. Results for heat transfer follow by analogy. The thermal or binary Nusselt number at small net mass transfer rates is given asymptotically by a generalized penetration expression \documentclass{article}\pagestyle{empty}\begin{document}$$ \langle Nu\rangle \, = \,a_{00} Pe^{1/2} \, + \,a_{01} Pe^0 \, + \,.\,.\,.\,{\rm (A)} $$\end{document} for short times, or for boundary layers that duplicate the surface tangential motion. For flows past rigid interfaces, the long-time average of 〈Nu〉 is given asymptotically by a generalized Chilton-Colburn relation \documentclass{article}\pagestyle{empty}\begin{document}$$ \langle \overline {Nu} \rangle \, = \,b_{00} Pe^{1/3} \, + \,b_{01} Pe^0 \, + \,.\,.\,.\,{\rm (B)} $$\end{document} in regions of nonrecirculating motion. The measurable functions aij and bij depend only on the system shape and laminar or turbulent velocity field. Formal expressions for a00 are given, and an expression for b00 in steady flows. These results agree well with data on mass transfer operations in tubes, packed beds, and fluid-fluid contactors.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690331211
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