DSMC simulations for assessment of Rarefaction Effects during NASA tests at SCIROCCO

A facility characterization test campaign was performed for NASA in SCIROCCO Plasma Wind Tunnel, with increasing enthalpy and constant reservoir pressure. In the frame of numerical rebuilding of the experimental data, an important gap among measured and CFD numerically predicted values of heat flux led to deep analyses the numerical methods and the models usually employed for test rebuilding. Since those evaluations have highlighted that the continuum breakdown was present, further numerical analyses were conducted employing two codes based on direct Simulation Monte Carlo (DSMC) model, in order to reduce the gap with the measured heat fluxes, and understand the actual test chamber environment. The DSMC was performed with DS2V Bird’s code and with dsmcFoam model available in the open source code OpenFoam. The DSMC results show heat flux levels quite near to the experimental data. Comparing the heat fluxes predicted by the two codes, appear that a key role is played from the chemical contributions.