Diffusion of methane in a mica slit pore: Molecular dynamics simulations and correlation models

Equilibrium molecular dynamics simulations have been used to calculate the self-diffusion coefficients of fluid methane confined in mica slit pore at different temperatures, densities and pore widths. On the other hand, based on the Chapman–Enskog theory and Heyes relationships, two simple correlation models which can describe the self-diffusion coefficient of fluid methane in mica slit pore are proposed as a function of the temperature, density and pore width. Both models are written in terms of Lennard-Jones (LJ) dimensionless variables, which are defined in terms of the LJ parameters σ and ε. These parameters are meaningful at molecular level. The validity of these models is evaluated by comparing with the calculated self-diffusion coefficient data at different state points. The average error of both these two models is usually less than 13%.