Molecular dynamics simulation of phase transformation process of n-tetradecane

doi:10.12028/j.issn.2095-4239.2019.0045

Abstract

Abstract: The molecular dynamics simulation method was used to simulate the amorphous tetradecane hydrocarbon system with COMPASS force field. The system was gradually heated from 270K to 290K under the NPT ensemble. The temperature-dependent diffusion of n-tetradecane molecules in the temperature range was analyzed. The phase transition temperature of the system was obtained at 278.5K. The obtained density value and phase transition temperature value are compared with the experimental results. The density error is 0.8% and the melting point error is 0.23%. The distribution of the terminal distance and the radial distribution function of the n-tetradecane molecular chain before and after the phase transition are also analyzed. It is found that the molecular chain conformation of n-tetradecane in solid state gradually changes from linear to curved with increasing temperature, while the conformation of molecular chain in liquid state gradually changes from curved to linear as the temperature increases. The possibility of presenting other molecules or atoms at 1.11 Å around the atom is the largest, and there are no other atoms in the 0.99 Å around the atom.The research results can be used to compare the changes of the microstructure of other molecular additives in the subsequent research, and to provide certain guidance for finding more efficient and practical phase change energy storage materials.

Key words: molecular dynamics, n-tetradecane, radial distribution function, diffusivity, end-to-end distance

CLC Number:

TK02

ZHANG Xuelai, WANG Xuzhe, WANG Jifen, XU Xiaofeng, HUA Weisan, FANG Manting. Molecular dynamics simulation of phase transformation process of n-tetradecane[J]. Energy Storage Science and Technology, 2019, 8(5): 874-879.

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