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8365056 
Journal Article 
Molecular Dynamics Simulation Study on Mass Diffusion Coefficient and Viscosity of CO2/n-Hexane System 
Wang, Y; Bi, SS; Cui, JW; Yan, SM; Wu, JT 
2020 
Science Press 
41 
7 
1579-1584 
Chinese 
In CO2 enhanced oil recovery technology (CO2-EOR), mass diffusion coefficient and viscosity parameters determine the diffusion behavior and flow characteristics of liquid phase mixture. In this paper, the diffusion coefficient and viscosity of CO2/n-hexane system were studied based on molecular dynamics simulation. The improved EPM2 model is used for CO2 and the L-OPLS model for n-hexane. The simulated pure density distribution and self-diffusion coefficient are in good agreement with the literature data. The mass diffusion coefficient and viscosity of CO2/n-hexane system under the conditions of temperature of 303.15 K, 383.15 K and pressure range of 1∼5 MPa were calculated by simulation. The results show that at the same temperature, with the increase of pressure, the relative deviation between the simulated and experimental values of diffusion coefficient increases, the most deviation is less than 20%. The relative deviation between the simulated viscosity value and the experimental value is less than 15%. The force field model and data processing method used in this paper can be used to estimate the diffusion coefficient and viscosity of CO2/n-hexane system. © 2020, Science Press. All right reserved. 
CO2/n-hexane; Diffusion coefficient; Molecular dynamics; Viscosity