Multiscale Study of Gas Slip Flows in Nanochannels

In this paper, a multi-scale modeling of the anisotropic slip phenomenon for gas flows is presented. The analysis is carried out by using two principal computational methods: the Density Functional Theory and the Molecular Dynamics approach. The ab-initio method is used to examine the interaction between the Pt-Ar gas-wall couple, and to determine the effective potential. The potential is then implemented into a MD code in order to simulate beam scattering experiments and to calculate the accommodation coefficients. The results are used to model the effective interaction for isotropic or anisotropic surfaces. Further MD simulations, based on the effective gas-wall model for anisotropic surfaces, are conducted. The slip effects are quantified numerically and compared with simplified theoretical models, also derived in this paper.