On the molecules rotational energy relaxation in the direct simulation Monte Carlo method

Rotational-translational (RT) energy exchange simulation in the direct simulation Monte Carlo method (DSMC) is under the consideration for the problem of hypersonic space vehicles planets (Earth, Mars, Venus, Titan and gas giants) atmosphere entrance. Systematization of the diatomic and polyatomic molecules discrete quantum energy levels is presented. Description of the energy exchange Larsen–Borgnakke algorithm is done for the molecules with discrete rotational energy levels. Variable hard spheres model parameters were derived for the planets atmospheres gases molecules from the viscosity experimental data and calculation molecules elastic cross sections. Rotation energy relaxation Parker’s formula parameters were chosen from the rotational energy relaxation times experimental data. Good agreement between calculation and experimental data was achieved for the fore body distance and width of shock wave before sphere in the nitrogen gas. It means that used models and their parameters are adequate.