Abstract: Density functional theory has been confirmed as a reliable approach in the descriptions of inhomogeneous fluids. By integrating the density functional theory into the revised local average density model, a theoretical approach is constructed to investigate the local shear viscosity in the confined conditions. In the density functional theory, the weighted density approximation for attractive part and the modified fundamental measure theory for repulsion contribution are adopted to accurately describe the inhomogeneous systems. By comparingwith simulation data, the theoretical model is tested. In this work, the shear viscosities of methane are calculated in different external fields (on a hard wall, a solvophobicwall and in slit pores with different widths). In addition, the effects of temperature on the local density and viscosity are also considered. It shows that the effect of temperature on the shear viscosity ismore obvious on solid surfaces. The calculation provides an approach to determine the viscosity under confined conditions, which is extremely significant in real industrial applications.

Key words: Viscosity, Methane, Statistical thermodynamics

摘要： Density functional theory has been confirmed as a reliable approach in the descriptions of inhomogeneous fluids. By integrating the density functional theory into the revised local average density model, a theoretical approach is constructed to investigate the local shear viscosity in the confined conditions. In the density functional theory, the weighted density approximation for attractive part and the modified fundamental measure theory for repulsion contribution are adopted to accurately describe the inhomogeneous systems. By comparingwith simulation data, the theoretical model is tested. In this work, the shear viscosities of methane are calculated in different external fields (on a hard wall, a solvophobicwall and in slit pores with different widths). In addition, the effects of temperature on the local density and viscosity are also considered. It shows that the effect of temperature on the shear viscosity ismore obvious on solid surfaces. The calculation provides an approach to determine the viscosity under confined conditions, which is extremely significant in real industrial applications.

关键词: Viscosity, Methane, Statistical thermodynamics