Molecular free paths in nanoscale gas flows

Barışık, Murat; Beşkök, Ali

doi:10.1007/s10404-014-1535-3

Cited by 34 publications

(36 citation statements)

References 27 publications

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“…Comparison of the velocity profiles obtained in MD with the linearized Boltzmann solutions at predicted Kn values shows good agreement in the bulk of the channels, while deviations in the near-wall region due to the influence of surface are observed (Barisik and Beskok 2015).…”

Section: Introductionmentioning

confidence: 83%

“…Gas flows in nanoscale domains are observed in a wide range of applications including the magnetic disk drives Using SWMD, we investigated shear-and force-driven nano-channel gas flows in the entire Knudsen regime (Barisik and Beskok 2010, 2011a, b, 2012, 2014, 2015. Simulation results have shown formation of a near-wall layer that is several molecular diameters thick.…”

Section: Introductionmentioning

confidence: 99%

“…• Transport in the bulk and near-wall regions is determined by the gas-wall interaction parameter and the Knudsen number (Barisik and Beskok 2011b;2012, 2014, 2015.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

“Law of the nano-wall” in nano-channel gas flows

Barışık

Beşkök

2016

Microfluid Nanofluid

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Section: Introductionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

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“Law of the nano-wall” in nano-channel gas flows

Barışık

Beşkök

2016

Microfluid Nanofluid

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“…For 0.1 b Kn b 10 flow is in transition regime (moderately rarefied). Finally, the flow is considered as free-molecular flow for large values of Kn (N10) (highly rarefied); the tool for dealing with this type flow is kinetic theory of gases, Direct Simulation of Monte Carlo (DSMC) [3] and Molecular Dynamics [4][5][6][7][8].…”

Section: Contents Lists Available At Sciencedirectmentioning

confidence: 99%

Analytical solution of thermally developing microtube heat transfer including axial conduction, viscous dissipation, and rarefaction effects

Barışık

Yazıcıoğlu

Çetin

et al. 2015

International Communications in Heat and Mass Transfer

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The solution of extended Graetz problem for micro-scale gas flows is performed by coupling of rarefaction, axial conduction and viscous dissipation at slip flow regime. The analytical coupling achieved by using Gram-Schmidt orthogonalization technique provides interrelated appearance of corresponding effects through the variation of non-dimensional numbers. The developing temperature field is determined by solving the energy equation locally together with the fully developed flow profile. Analytical solutions of local temperature distribution, and local and fully developed Nusselt number are obtained in terms of dimensionless parameters: Peclet number, Knudsen number, Brinkman number, and the parameter Kappa accounting temperature-jump. The results indicate that the Nusselt number decreases with increasing Knudsen number as a result of the increase of temperature jump at the wall. For low Peclet number values, temperature gradients and the resulting temperature jump at the pipe wall cause Knudsen number to develop higher effect on flow. Axial conduction should not be neglected for Peclet number values less than 100 for all cases without viscous dissipation, and for short pipes with viscous dissipation. The effect of viscous heating should be considered even for small Brinkman number values with large length over diameter ratios. For a fixed Kappa value, the deviation from continuum increases with increasing rarefaction, and Nusselt number values decrease with an increase in Knudsen number.

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“…Others argue that the collisions between the freely moving gas molecules and wall atoms or adsorbed gas molecules should be disregarded when evaluating the individual free paths, and then show that the boundary-independent MFP given by Eq. (2) is recovered [9].…”

Section: Introductionmentioning

confidence: 99%

Variation of molecular mean free path in confined geometries

Xie

Gibelli

Borg

et al. 2019

31st International Symposium on Rarefied Gas Dynamics: Rgd31

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This paper aims to settle disputes in the literature about the spatial variation of the molecular mean free path (MFP) in confined geometries. The MFP of a gas is determined by using both molecular dynamics (MD) and the direct simulation Monte Carlo (DSMC) technique. In spatially-homogeneous cases, the numerical results exactly recover the kinetic theory predictions of a constant MFP. However, in microchannels, the MFP is found to vary near to the bounding walls and reduce at the surfaces to half of its bulk value as long as collisions between gas molecules and wall atoms are taken into account in the calculation of the MFP.

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Molecular free paths in nanoscale gas flows

Cited by 34 publications

References 27 publications

“Law of the nano-wall” in nano-channel gas flows

“Law of the nano-wall” in nano-channel gas flows

Analytical solution of thermally developing microtube heat transfer including axial conduction, viscous dissipation, and rarefaction effects

Variation of molecular mean free path in confined geometries

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