Strathprints Home | Open Access | Browse | Search | User area | Copyright | Help | Library Home | SUPrimo

A wall-function approach to incorporating Knudsen-layer effects in gas micro flow simulations

Lockerby, Duncan A. and Reese, Jason and Gallis, Michael A. (2004) A wall-function approach to incorporating Knudsen-layer effects in gas micro flow simulations. In: Rarefied Gas Dynamics. AIP Conference Proceedings, 762 . American Institute of Physics, pp. 731-736. ISBN 0-7354-0247-7

[img]
Preview
PDF - Submitted Version
Download (432Kb) | Preview

    Abstract

    For gas flows in microfluidic configurations, the Knudsen layer close to the wall can comprise a substantial part of the entire flow field and has a major effect on quantities such as the mass flow rate through micro devices. The Knudsen layer itself is characterized by a highly nonlinear relationship between the viscous stress and the strain rate of the gas, so even if the Navier-Stokes equations can be used to describe the core gas flow they are certainly inappropriate for the Knudsen layer itself. In this paper we propose a "wall-function" model for the stress/strain rate relations in the Knudsen layer. The constitutive structure of the Knudsen layer has been derived from results from kinetic theory for isothermal shear flow over a planar surface. We investigate the ability of this simplified model to predict Knudsen-layer effects in a variety of configurations. We further propose a semi-empirical Knudsen-number correction to this wall function, based on high-accuracy DSMC results, to extend the predictive capabilities of the model to greater degrees of rarefaction.

    Item type: Book Section
    ID code: 32109
    Notes: Book - Online Proceedings
    Keywords: knudsen layer, wall-function, gas microflows, Mechanical engineering and machinery, Physics
    Subjects: Technology > Mechanical engineering and machinery
    Science > Physics
    Department: Faculty of Engineering > Mechanical and Aerospace Engineering
    Related URLs:
    Depositing user: Pure Administrator
    Date Deposited: 21 Jul 2011 15:35
    Last modified: 10 Jun 2014 12:53
    URI: http://strathprints.strath.ac.uk/id/eprint/32109

    Actions (login required)

    View Item

    Fulltext Downloads: