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Modeling of Knudsen layer effects in micro/nanoscale gas flows

Dongari, Nishanth and Zhang, Yonghao and Reese, Jason (2011) Modeling of Knudsen layer effects in micro/nanoscale gas flows. Journal of Fluids Engineering, 133 (7). ISSN 0098-2202

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Abstract

We propose a power-law based effective mean free path (MFP) model so that the Navier-Stokes-Fourier equations can be employed for the transition-regime flows typical of gas micro/nanodevices. The effective MFP model is derived for a system with planar wall confinement by taking into account the boundary limiting effects on the molecular free paths. Our model is validated against molecular dynamics simulation data and compared with other theoretical models. As gas transport properties can be related to the mean free path through kinetic theory, the Navier-Stokes-Fourier constitutive relations are then modified in order to better capture the flow behavior in the Knudsen layers close to surfaces. Our model is applied to fully developed isothermal pressure-driven (Poiseuille) and thermal creep gas flows in microchannels. The results show that our approach greatly improves the near-wall accuracy of the Navier-Stokes-Fourier equations, well beyond the slip-flow regime.

Item type: Article
ID code: 32221
Keywords: creeping flow, kinetic theory, Knudsen flow, microchannel flor, Poiseuille flow , navier stokes equations, Mechanical engineering and machinery, Solid state physics. Nanoscience, Mechanical Engineering, Computational Mechanics, Modelling and Simulation
Subjects: Technology > Mechanical engineering and machinery
Science > Physics > Solid state physics. Nanoscience
Department: Faculty of Engineering > Mechanical and Aerospace Engineering
Technology and Innovation Centre > Advanced Engineering and Manufacturing
Depositing user: Pure Administrator
Date Deposited: 21 Jul 2011 09:01
Last modified: 15 Apr 2015 11:41
Related URLs:
URI: http://strathprints.strath.ac.uk/id/eprint/32221

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