Dresden 2006 – wissenschaftliches Programm

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DY: Dynamik und Statistische Physik

DY 46: Poster

DY 46.17: Poster

Donnerstag, 30. März 2006, 16:00–18:00, P1

Gas diffusion in three-dimensional porous media in the Knudsen regime — •Stephan Zschiegner^1,2, Stefanie Ruß¹, Armin Bunde¹, and Jörg Kärger² — ¹Institut für Theoretische Physik III, JLU Giessen — ²Institut für Experimentelle Physik I, Universität Leipzig

In general, diffusion of gas particles depends on the collisions between the gas molecules as well as on the collisions of the gas with the pore walls. Of particular interest for many real gases is the range of the so-called Knudsen regime, where the interaction of the molecules with the pore walls plays the crucial role and intermolecular collisions can be neclected.

We implement pores with different roughness by considering the first four iterations of a generalized fractal Koch curve in three dimensions. For these model pores we have performed detailed investigations of self-diffusion and transport diffusion. We show that the diffusion can be mapped onto Levy walks and discuss the roughness dependence of the diffusion coefficients D_s and D_t of self- and transport diffusion, respectively. With further enhancement, by additionally calculating the statistical concentration within the pore, our results show equality of both diffusion coefficients D_s and D_t.