The flux-ratio for binary counterdiffusion of ideal gases

✍ Scribed by F.A.L. Dullien; D.S. Scott

• Publisher: Elsevier Science
• Year: 1962
• Tongue: English
• Weight: 383 KB
• Volume: 17
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(62)80064-5

✦ Synopsis

It is shown in an analytical treatment, using some fundamental principles of hydrodynamics and the elementary kinetic theory of gases that in ordinary (as opposed to Knudsen) steady-state counterdiffusion of a binary gaseous system, at constant total pressure and temperature, the ratio of the two molar fluxes is, in a very close approximation, equal to the square root of the inverse ratio of the respective molecular weights. This result which has been shown so far to hold only for Knudsen diffusion seems to apply at all practical diameters of the diffusion channels normally encountered in porous solid materials. It does not apply, however, in the case of selective surface migration.