High fidelity modeling of energy transfer and chemical reactions in shock waves

In this work, newly-developed MD-QCT databases¹ for chemical reaction and interal energy relaxation are implemented progressively in DSMC simulations of heat bath cases and normal shocks in nitrogen and the results are compared with those obtained using the traditional TCE and LB models. In the heat bath cases the MD-QCT chemical reaction model predicts more dissociation and less nonequilibrium eventually and faster relaxation of the vibrational temperature compared with using the TCE-LB models. In the lower speed one-dimensional unsteady shocks cases, the flow field results exhibit similar behavior as those seen in the heat bath case when the MD-QCT databases are progressively added. Finally, in the even higher speed shock conditions as those appeared in the experiments by Fujita et al., the use of MD-QCT databases for both chemical reaction and interal energy predicts more dissociation in the downstream of the shock but slower relaxation of the rotational temperature than using the TCE and LB models. Furthermore, the rotational temperature in the shock region is in better agreement with experiments and confirms that large rotational nonequilibrium is present in very strong nitrogen shocks.