Molecular Dynamics Study of Gas-Surface Interactions on β-Cristobalite Surface

In the present work, nonreactive gas-surface interactions between nitrogen molecules and a beta- cristobalite surface are analyzed using the molecular dynamics framework. A sampling method is employed to perform trajectory calculations, and the tangential momentum accommodation coefficient is computed. The credibility of the reactive force field potential to model beta cristobalite is investigated, and the effect of the surface and gas temperatures on the tangential momentum accommodation coefficient is studied in detail. The obtained value of the tangential momentum accommodation coefficient (from molecular dynamics analysis) is used as an input parameter in the Maxwell gassurface interaction model using the direct simulation Monte Carlo method to investigate the surface heat flux on the nose region of a model reentry vehicle. The computed heat-flux results obtained using a molecular-dynamics-derived accommodation coefficient are found to be in excellent agreement with the experimental data.