A new correlation on predicting self- and mutual-diffusion coefficient of Lennard-Jones chain fluid

Based on the Chapman-Enskog theory of diffusion and molecular dynamics simulation data for Lennard-Jones chain (LJC) fluid, a new semi-empirical correlation for calculating the self-diffusion coefficient of LJC fluid is proposed. The new correlation introduces in two correction functions with six fitting parameter to modify the impact of intermolecular repulsive and attractive potential energy on molecular friction coefficient. The new correlation represents the experimental self-diffusion coefficients with an average absolute deviation (AAD) of 3.46% for 23 polyatomic compounds (1102 experimental data points) over wide ranges of temperature and pressure. On this basis, the van der Waals mixing rule is adopted to calculate the mutual-diffusion coefficient of binary LJC fluid. By comparison of calculated results with the experimental data of 12 binary LJC systems over wide range of temperature and composition, the average absolute deviation is 6.98% which verifies the accuracy and the effectiveness of the new correlation.