Sensitivity Analysis of DSMC Parameters for an 11-Species Air Hypersonic Flow

This research investigates the influence of input parameters in the direct simulation Monte Carlo (DSMC) method for the simulation of a hypersonic flow scenario. Simulations are performed using the Computation of Hypersonic Ionizing Particles in Shocks (CHIPS) code to reproduce NASA Ames Electric Arc Shock Tube ( EAST) experimental results for a 10.26 km/s, 0.2 Torr scenario. Since the chosen nominal simulation involves an energetic flow, an electronic excitation model is introduced into CHIPS to complement the pre-existing 11-species air models. A global Monte Carlo sensitivity analysis was completed for this chosen scenario and three quantities of interest (QoIs) were investigated: translational temperature, electronic temperature, and electron number density. The electron impact ionization reaction, N + e(-) reversible arrow N+ + e(-) + e(-), was determined to have the greatest effect on all three QoIs as it defines the electron cascade that occurs post-shock. In addition, molecular nitrogen dissociation, associative ionization, and the N + NO+ reversible arrow N+ + NO charge exchange reaction were all found to be important for these QoIs.