Comparison of Efficiency Equilibrium and Non-Equilibrium Molecular Dynamics Calculations of Thermal Diffusion Factor

2007 ◽  
Vol 76 (4) ◽  
pp. 044601 ◽  
Author(s):  
Saeed Yeganegi ◽  
Mojdeh Anbarfam
Keyword(s):  
Molecular Dynamics ◽  
Thermal Diffusion ◽  
Diffusion Factor ◽  
Thermal Diffusion Factor ◽  
Molecular Dynamics Calculations ◽  
Non Equilibrium Molecular Dynamics ◽  
Non Equilibrium

Non-Equilibrium Molecular Dynamics Study of the Influence of Branching on the Soret Coefficient of Binary Mixtures of Heptane Isomers

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Xiaoyu Chen ◽  
Ruquan Liang ◽  
Lichun Wu ◽  
Gan Cui
Keyword(s):  
Molecular Dynamics ◽  
Thermal Diffusion ◽  
Soret Coefficient ◽  
Isomer Mixture ◽  
Acentric Factor ◽  
Diffusion Behavior ◽  
The Difference ◽  
Non Equilibrium Molecular Dynamics ◽  
Molecular Branching ◽  
Non Equilibrium

Abstract Equimolar mixtures composed of isomers were firstly used to investigate the molecular branching effect on thermal diffusion behavior, which was not disturbed by factors of molecular mass and composition in this work. Eight heptane isomers, including n-heptane, 2-methylhexane, 3-methylhexane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane and 3-ethylpentane, were chosen as the researched mixtures. A non-equilibrium molecular dynamics (NEMD) simulation with enhanced heat exchange (eHEX) algorithm was applied to calculate the Soret coefficient at T = 303.15 T=303.15  K and P = 1.0 atm P=1.0\hspace{0.1667em}\text{atm} . An empirical correlation based on an acentric factor was proposed and its calculation coincides with the simulated results, which showed the validity of the NEMD simulation. It is demonstrated that the isomer with higher acentric factor has a stronger thermophilic property and tends to migrate to the hot region in the heptane isomer mixture, and the extent of thermal diffusion is proportional to the difference between the acentric factors of the isomers.

Molecular Dynamics Calculations of InSb Thermal Conductivity

2010 ◽  
Vol 297-301 ◽  
pp. 1400-1407
Author(s):  
Giovano de Oliveira Cardozo ◽  
José Pedro Rino
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Molecular Dynamics ◽  
Infinite System ◽  
Thermal Conductivity Coefficient ◽  
Direct Method ◽  
Molecular Dynamics Calculations ◽  
Non Equilibrium Molecular Dynamics ◽  
Three Body ◽  
Non Equilibrium

Equilibrium and non-equilibrium molecular dynamics calculations of thermal conductivity coefficient are presented for bulk systems of InSb, using an effective two- and three-body inter atomic potential which demonstrated to be very transferable. In the calculations, the obtained coefficients were comparable to the experimental data. In the case of equilibrium simulations a Green-Kubo approach was used and the thermal conductivity was calculated for five temperatures between 300 K and 900 K. For the non equilibrium, or direct method, which is based on the Fourier’s law, the thermal conductivity coefficient was determined at a mean temperature of 300K. In this case it was used a pair of reservoirs, placed at a distance L from each other, and with internal temperatures fixed in 250 K, for the cold reservoir, and 350 K for the hot one. In order to obtain an approach to an infinite system coefficient, four different values of L were used, and the data was extrapolated to L→∞.

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