Effect of Wall Characteristics on the Behaviors of Reflected Gas Molecules in a Thermal Problem

Yamamoto, Kazuomi; Takeuchi, Hideki; Hyakutake, Toru

doi:10.1063/1.1581650

Cited by 10 publications

(21 citation statements)

References 1 publication

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“…The impinging gas molecules were considered to interact only with the wall and the Morse potential values with larger 1 Ar -Pt (about 1.859 £ 10 221 J, twice of that in this paper) were used for the gas -wall interactions. Since a stronger gaswall interaction potential will lead to more accommodation with the wall, the non-equilibrium EAC for smooth walls in [14] (0.43) and [15] (0.41 -0.49) is larger than the data in our simulations (all less than 0.2). Therefore, the interaction potential and the related parameters in MD simulation should be paid more attention to.…”

Section: Resultscontrasting

confidence: 62%

“…Yamamoto [14] and Yamamoto et al [15] also calculated the non-equilibrium EAC for Ar gas and Pt wall interactions in a micro-thermal conduction problem using MD method coupled with DSMC method. The impinging gas molecules were considered to interact only with the wall and the Morse potential values with larger 1 Ar -Pt (about 1.859 £ 10 221 J, twice of that in this paper) were used for the gas -wall interactions.…”

Section: Resultsmentioning

confidence: 98%

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Molecular dynamics simulations of energy accommodation coefficients for gas flows in nano-channels

Sun

2009

Molecular Simulation

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The energy accommodation coefficient (EAC) used in thermal boundary condition in micro-and nano-gas flows is reported to be always less than unity and greatly influenced by wall characteristics, for example, the wall temperature. A statistical EAC definition was described to calculate the EAC for thermal conduction in argon gas between two smooth platinum plates from two-dimensional non-equilibrium molecular dynamics simulations. The non-equilibrium EAC at the upper wall was calculated for different upper wall temperatures and a fixed bottom wall temperature. The equilibrium EAC at each temperature can then be extrapolated from a series of non-equilibrium EACs as the temperature difference between the two walls approaches zero. The analyses of the effects of wall temperature for various Knudsen number on non-equilibrium and equilibrium EACs show that, for a given lower bottom wall temperature, the non-equilibrium EAC at a high temperature wall increases with an increase in the wall temperature. For a given wall temperature difference, the non-equilibrium EAC increases with the increase in the wall temperatures. The equilibrium EAC also becomes larger at higher temperatures.

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Section: Resultscontrasting

confidence: 62%

Section: Resultsmentioning

confidence: 98%

Molecular dynamics simulations of energy accommodation coefficients for gas flows in nano-channels

Sun

2009

Molecular Simulation

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“…In their simulations, the accommodation coefficients were definitely influenced by the roughness and the adsorbed gas molecules above the surface. It was confusing that the EAC values on rough surfaces [15] were smaller than those coefficients on smooth surfaces. Generally speaking, roughness always induces more flow resistance so that the TMAC and EAC in rough channels must be larger than those in smooth channels.…”

Section: Introductionmentioning

confidence: 97%

“…Moreover, even in smooth surfaces, the atom arrangement of the wall materials would induce atomic roughness from the atomic viewpoint and also affect the fluid flow and heat transfer [19]. Since the aforementioned roughness in reference [15] is about 0.5 nm, which is also on the atomic scale, the effect of atomic roughness in various lattice configurations was considered as one part. In the following sections, the concepts of the accommodation coefficients are explained to introduce the algorithm.…”

Section: Introductionmentioning

confidence: 99%

“…With the development of technologies and applications in micro and nano flows, MD simulations of gas flows in microchannels and nanochannels also draw much concentration [12,13]. Yamamoto [14] and Yamamoto et al [15,16] coupled the MD and direct simulation Monte Carlo (DSMC [17,18]) methods to simulate gas flows in nanochannels, in which the molecular motions near the wall and the accommodation coefficients were calculated using the MD method. In their simulations, the accommodation coefficients were definitely influenced by the roughness and the adsorbed gas molecules above the surface.…”

Section: Introductionmentioning

confidence: 99%

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Three-Dimensional Molecular Dynamic Study on Accommodation Coefficients in Rough Nanochannels

Sun

2011

Heat Transfer Engineering

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The tangential momentum and energy accommodation coefficients (TMAC and EAC) are parameters to characterize the velocity slip and temperature jump in the gas-solid interface. To understand the wall effects on fluid flow and heat transfer in nanochannels, the accommodation coefficients for argon gas molecules and platinum wall atoms were calculated according to a proper statistical algorithm using a three-dimensional molecular dynamic method. Isothermal flows and thermal conductions were simulated in smooth and rough nanochannels, in which the roughness ranged from 0.2 nm to 1.4 nm. From the atomic viewpoint, different lattice arrangements of smooth walls would induce atomic roughness to different extents on the surface, which affected the momentum and energy exchange in gas-wall interactions and resulted in different accommodation coefficients. In channels with nanoscale roughness, the possibility of multiple gas-wall interactions were further increased so that the TMAC and EAC became much larger with more roughness.

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Numerical simulation of novel gas separation effect in microchannel with a series of oscillating barriers

Kosyanchuk

Yakunchikov

Bryukhanov

et al. 2017

Microfluid Nanofluid

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Effect of Wall Characteristics on the Behaviors of Reflected Gas Molecules in a Thermal Problem

Cited by 10 publications

References 1 publication

Molecular dynamics simulations of energy accommodation coefficients for gas flows in nano-channels

Molecular dynamics simulations of energy accommodation coefficients for gas flows in nano-channels

Three-Dimensional Molecular Dynamic Study on Accommodation Coefficients in Rough Nanochannels

Numerical simulation of novel gas separation effect in microchannel with a series of oscillating barriers

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