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DY: Fachverband Dynamik und Statistische Physik
DY 5: Fluid dynamics I
DY 5.6: Talk
Monday, March 26, 2007, 15:30–15:45, H2
Gas Flow through Nanopores — •Simon Grüner and Patrick Huber — Saarland University, Saarbrücken, Germany
We present gas flow experiments on both narrow capillaries and silicon membranes which are permeated by a bundle of parallel, tubular channels of approx. 10nm diameter. Applying pressures between 1 and 10−5bar this arrangement allows us to study flows of compressible fluids over a wide range of Knudsen numbers, Kn, which refers to the ratio of the mean free path λ to the channel diameter. We find for both helium and argon gas flow the expected breakdown of continuum-like behavior at Kn ≈ 0.45. At higher Kn, on the other hand, the flow dynamics is in perfect agreement with a Knudsen diffusion-like particle transport. This is confirmed by measurements of temperature and molar mass dependencies of the diffusion coefficient D.
In our latest experiments we’ve been probing the influence of pore wall modification on the helium gas diffusion through the nanopores via condensing monolayers of argon at T=30K.