An Enskog based Monte Carlo method for high Knudsen number non-ideal gas flows

A Monte Carlo method based on the Enskog equation for dense gas is developed by considering high density effect on collision rates and both repulsive and attractive molecular interactions for a Lennard–Jones fluid. The appropriate internal energy exchange model is introduced with consistency with the collision model. The equation of state for a non-ideal gas is therefore derived involving the finite density effect and the van der Waals intermolecular force, changing from the Clapeyron equation to the van der Waals equation. In contrast to previous Monte Carlo approaches, the present predictions agree better with experimental data for the gas transport properties at high densities and in a wide temperature region. The numerical modeling of non-ideal gas flow in micro and nanochannels show that the high gas density affects greatly flow behavior and heat transfer characteristics. The high density of gas leads to a lower skin friction coefficient on the wall surfaces than the predictions by the perfect gas assumption.