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An alternative procedure for modeling of Knudsen flow and surface diffusion
Publikationstyp
Journal Article
Date Issued
2008
Sprache
English
Author(s)
Keil, Frerich
Institut
TORE-URI
Volume
52
Issue
2
Start Page
37
End Page
55
Citation
Periodica Polytechnica - Chemical Engineering 52 (2): 37-55 (2008)
Publisher DOI
Scopus ID
Publisher
Budapest University of Technology and Economics
An alternative procedure for the calculation of impingement rate distribution and simultaneously the transmission probability in pores under Knudsen diffusion conditions is introduced. It is based on a combination of the finite difference method and a projection approach. Pore entrance and exit effects, and the influence of the pore length on diffusive fluxes are investigated. Later on, it is applied for a simultaneous Knudsen and surface flow system. In the model, the equation system is built without the independent flow and adsorption-desorption equilibrium assumptions. For the conditions investigated, the results indicate that if the surface flow rate is substantial, the independent flow and adsorption equilibrium assumptions become improper estimates for the behaviour of the system. The surface and gas flow rates, the impingement rate distribution and the surface coverage behave much more complex than the characteristics found with such assumptions.
Subjects
Cylindrical pore
Equilibrium assumption
Knudsen flow
Projection approach
Surface diffusion
DDC Class
540: Chemie
620: Ingenieurwissenschaften