Accession Number:

AD0266266

Title:

THE DIFFUSIONAL CONTRIBUTION TO THE KNUDSEN CELL EFFUSION FLUX

Descriptive Note:

Corporate Author:

METAL HYDRIDES INC BEVERLY MASS

Personal Author(s):

Report Date:

1961-12-01

Pagination or Media Count:

1.0

Abstract:

I T I RECOGNIZED THAT THE GEOMETRY OF A Knudsen vapor effusion cell influences the kinetics of the molecular effusion of the vapor from within the cell. Clausing, Whit an and Motzfeldt have given treatments which allow for the correction of the effusion flux to account for these factors so that the flux obtained will reflect the actual vapor pressure within the cell. Ho ever, no treatment has been reported of the contribution to the effusion flux made by the surface diffusion out through the orifice of the effusate adsorbed on the cell walls. Tre ting the steady state kinetics for both surface diffusion and vapor effusion out through the orifice the applicable differential equations for this model were solved approximately. Although the required thermodynamic data is sparse, the derived relations indicate the diffusion flux for the orifice dimensions commonly employed may contribute an appreciable fraction of the total weight loss of the cell during an effusion experiment. If not taken in o account this diffusional contribution would yield equilibrium vapor pr ur i exc s of the actual values. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE