Molecular-dynamics study on characteristics of energy and tangential momentum accommodation coefficients

2017 ◽  
Vol 96 (1) ◽  
Author(s):  
Hiroki Yamaguchi ◽  
Yu Matsuda ◽  
Tomohide Niimi
Keyword(s):  
Molecular Dynamics ◽  
Accommodation Coefficients ◽  
Tangential Momentum

scholarly journals The Influence of Gas–Wall and Gas–Gas Interactions on the Accommodation Coefficients for Rarefied Gases: A Molecular Dynamics Study

Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 319 ◽  
Author(s):  
Shahin Mohammad Nejad ◽  
Silvia Nedea ◽  
Arjan Frijns ◽  
David Smeulders
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Rarefied Gas ◽  
Interaction Strength ◽  
Gold Surface ◽  
Md Simulations ◽  
Accommodation Coefficients ◽  
Experimental Values ◽  
Energy And Momentum ◽  
Gas Interactions

Molecular dynamics (MD) simulations are conducted to determine energy and momentum accommodation coefficients at the interface between rarefied gas and solid walls. The MD simulation setup consists of two parallel walls, and of inert gas confined between them. Different mixing rules, as well as existing ab-initio computations combined with interatomic Lennard-Jones potentials were employed in MD simulations to investigate the corresponding effects of gas-surface interaction strength on accommodation coefficients for Argon and Helium gases on a gold surface. Comparing the obtained MD results for accommodation coefficients with empirical and numerical values in the literature revealed that the interaction potential based on ab-initio calculations is the most reliable one for computing accommodation coefficients. Finally, it is shown that gas–gas interactions in the two parallel walls approach led to an enhancement in computed accommodation coefficients compared to the molecular beam approach. The values for the two parallel walls approach are also closer to the experimental values.

Heat Transfer Predictions for Micro-/Nanochannels at the Atomistic Level Using Combined Molecular Dynamics and Monte Carlo Techniques

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
S. V. Nedea ◽  
A. J. Markvoort ◽  
A. A. van Steenhoven ◽  
P. A. J. Hilbers
Keyword(s):  
Molecular Dynamics ◽  
Heat Flux ◽  
Monte Carlo ◽  
Boundary Conditions ◽  
Accommodation Coefficient ◽  
Monte Carlo Techniques ◽  
Effective Coefficients ◽  
Accommodation Coefficients ◽  
Dynamics Simulations ◽  
Wall Interactions

The thermal behavior of a gas confined between two parallel walls is investigated. Wall effects such as hydrophobic or hydrophilic wall interactions are studied, and the effect on the heat flux and other characteristic parameters such as density and temperature is shown. For a dilute gas, the dependence on gas-wall interactions of the temperature profile between the walls for the incident and reflected molecules is obtained using molecular dynamics (MD). From these profiles, the effective accommodation coefficients for different interactions and different mass fluid/wall ratio are derived. We show that Monte Carlo (MC) with Maxwell boundary conditions based on the accommodation coefficient gives good results for heat flux predictions when compared with pure molecular dynamics simulations. We use these effective coefficients to compute the heat flux predictions for a dense gas using MD and MC with Maxwell-like boundary conditions.

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