Diffusion of gases in graphite pores. Project DRAGON

Technical Report · Wed Aug 15 04:00:00 EDT 1962

OSTI ID:4104094

Truitt, J.; Evans, III, R. B. ^[1]; Mason, E. A. ^[2]

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1. Reactor Chemistry Division, Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (US)
2. Institute of Molecular Physics, University of Maryland (US)

A system of equations have been adopted for the diffusion of gases in graphite pores in the absence of temperatuer and pressure gradients. Portions of the medium are visualized as a collection of fixed "dust" particles whcih are uniformly distributed. The results apply over the entire pressure range from the Knudsen region to the normal diffusion region. This approach permits a satisfactory explanation of the fact that over wide pressure ranges the flux ratio of two counter-diffusing gases is (m{sub 2}/m{sub 1}{sup 1/2} in porous media under steady-state and uniform-pressure conitions. The effect of non-uniform pressures on the diffusion equations is to introduce both a pressure diffusion term and an external force term. However, the final diffusion equation has the same form as in teh uniform pressure case. No additional parameters are required to compute the diffusion rates when pressure gradients are present. A complete solution requires also a forced flow equation giving J (the net flux) as a function of the pressure gradient. A forced flow equation is derived on the basis of the dusty-gas concept, but one parameter must be made disposable in order to compensate for the fact that the diffusion equations permit only a diffusive mechanism for flow, neer a viscous mechanism. A series of experiments with one gas mixture is discussed. (auth)

• Research Organization: Atomic Energy Establishment (AEE), Winfrith, England (United Kingdom)
• Sponsoring Organization: Atomic Energy Establishment (AEE)
• NSA Number: NSA-24-042227
• OSTI ID: 4104094
• Report Number(s): DP-Report--111; CONF-620305--2
• Country of Publication: United Kingdom
• Language: English

Related Subjects

DIFFUSION
EQUATIONS
GASES
GASES/diffusion in graphite
equations for calculation of
GRAPHITE
GRAPHITE/diffusion of gases in
equations for calculation of
N20230 --Chemistry--Inorganic
Organic
& Physical Chemistry--Physical Chemistry
N30230* --Metals
Ceramics
& Other Materials--Ceramics & Cermets--Properties Evaluations