The dusty-gas model is an empirical formulation commonly used to describe gas flows in porous media. While experiments have validated the model for pores with high aspect ratios, a validation for near-unity aspect ratios is lacking. We used direct simulation Monte Carlo to evaluate the accuracy of the dusty-gas model for binary diffusion in low aspect ratio capillaries. Our results suggest that the dusty-gas model deviates from the Monte Carlo simulations by less than 3% for aspect ratios ≥ 1, thus supporting its …