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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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.
|Keywords:||creeping flow, kinetic theory, Knudsen flow, microchannel flor, Poiseuille flow , navier stokes equations, Mechanical engineering and machinery, Solid state physics. Nanoscience|
|Subjects:||Technology > Mechanical engineering and machinery|
Science > Physics > Solid state physics. Nanoscience
|Department:||Faculty of Engineering > Mechanical and Aerospace Engineering|
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|Depositing user:||Pure Administrator|
|Date Deposited:||21 Jul 2011 10:01|
|Last modified:||08 Dec 2013 22:49|
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