A specific slip length model for the Maxwell slip boundary conditions in the Navier–Stokes solution of flow around a microparticle in the no-slip and slip flow regimes

Wedel, J., Štrakl, M., Ravnik, J., Steinmann, P. and Hriberšek, M. (2022) A specific slip length model for the Maxwell slip boundary conditions in the Navier–Stokes solution of flow around a microparticle in the no-slip and slip flow regimes. Theoretical and Computational Fluid Dynamics, 36, pp. 723-740. (doi: 10.1007/s00162-022-00627-w)

Abstract

In the case of microscopic particles, the momentum exchange between the particle and the gas flow starts to deviate from the standard macroscopic particle case, i.e. the no-slip case, with slip flow occurring in the case of low to moderate particle Knudsen numbers. In order to derive new drag force models that are valid also in the slip flow regime for the case of non-spherical particles of arbitrary shapes using computational fluid dynamics, the no-slip conditions at the particle surface have to be modified in order to account for the velocity slip at the surface, mostly in the form of the Maxwell’s slip model. To allow a continuous transition in the boundary condition at the wall from the no-slip case to the slip cases for various Knudsen (Kn) number value flow regimes, a novel specific slip length model for the use with the Maxwell boundary conditions is proposed. The model is derived based on the data from the published experimental studies on spherical microparticle drag force correlations and Cunningham-based slip correction factors at standard conditions and uses a detailed CFD study on microparticle fluid dynamics to determine the correct values of the specific slip length at selected Kn number conditions. The obtained data on specific slip length are correlated using a polynomial function, resulting in the specific slip length model for the no-slip and slip flow regimes that can be applied to arbitrary convex particle shapes.

• Item Type: Articles
• Additional Information: Funding: Open Access funding enabled and organized by Projekt DEAL.
• Keywords: Original Article, Slip flow regime, Drag force, Maxwell slip velocity, Tangential momentum accommodation coefficient, Slip length, Computational fluid dynamics
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Steinmann, Professor Paul
• Authors: Wedel, J., Štrakl, M., Ravnik, J., Steinmann, P., and Hriberšek, M.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Theoretical and Computational Fluid Dynamics
• Publisher: Springer
• ISSN: 0935-4964
• ISSN (Online): 1432-2250
• Published Online: 07 September 2022
• Copyright Holders: Copyright © The Author(s) 2022
• First Published: First published in Theoretical and Computational Fluid Dynamics 36: 723-740
• Publisher Policy: Reproduced under a Creative Commons License