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Flow of gases in isothermal prismatic channels at arbitrary Knudsen-numbers / Stroemung von Gasen in prismatischen Kanaelen konstanter Temperatur bei beliebigen Knudsen-Zahlen

  • Class, A.G.
  • Class, G.
  • karlsruhe, forschungszentrum
Publication Date
Jan 01, 2004
OpenGrey Repository


For rarified gas flow in ducts or channels of prismatic cross section a minimum of the flow resistance, which is known since 1909, is observed for Knudsen-number ranging from 1 to 10. In the present study a closed relation for the flow resistance is proposed and physically justified. This relation should not be interpreted as an interpolation formula. The relation is applicable to any Knudsen-number and channels of arbitrary length. However, potential accommodation effects are not considered yet. Employing recent experimental data from the literature the model is verified for a wide range of parameters and new physical insight is gained with respect to the flow resistance of short channels and orifice plates when Knudsen-flow is approached. The present study allows for improved computations of channel flow in all vacuum technology applications. Furthermore, we provide methods to extend our results to other isothermal prismatic channel cross sections, which are not explicitly studied in the present work, without resorting to additional experimental data. In the present study we provide the first phenomenological explanation of the Knudsen-minimum. (orig.) / Available from TIB Hannover: ZA 5141(6995) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische Informationsbibliothek / SIGLE / DE / Germany

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