HS‐PPM simulation for diffusion coefficients of binary and multi‐component gas mixtures

Abstract The Maxwell‐Stefan equation requires mutual diffusion coefficients between any two components and average concentration gradients to calculate multi‐component diffusion fluxes. However, empirical formulas for mutual diffusion coefficients have limitations due to the assumption of ideal gas or reliance on restricted experimental data, while standard molecular dynamics (MD) simulation requires a large number of simulations and high computational cost. To address these limitations, a non‐equilibrium MD simulation approach was developed by combining hard‐sphere/pseudo‐particle modeling (HS‐PPM) and the reverse non‐equilibrium MD method. This approach allows for the determination of equivalent diffusion coefficients and fluxes for each component in multi‐component gas mixtures with specified composition ratios. The obtained diffusion coefficients showed good agreement with experimental data, and the proposed method is much more efficient than the standard MD simulation. It demonstrates that the non‐equilibrium HS‐PPM approach can provide an accurate and efficient method for simulating the multi‐component diffusion, especially at the nano‐/micro‐scales.