Uncertainty Calibration of Surface Probe Predictions and Experimental Data in the NASA HyMETS Arc-Jet Facility

The objective of this work is to present a model calibration approach, including uncertainties considered in model parameter inputs, applied to a slug calorimeter heat flux gauge in NASA Langley’s Hypersonic Materials Environmental Test System arc-jet facility. The calibration results are presented for a low- and high-enthalpy condition for selected calibration model parameters, including the N2-N2 collision integral, nozzle and slug calorimeter catalytic efficiencies, and arc heater experimental measurements informed by sensitivity analysis. Results indicate the slug calorimeter atomic oxygen and nitrogen recombination efficiencies follow a Gaussian distribution with a mean of 0.16 and 0.011 respectively, assuming that the oxygen catalytic behavior and uncertainty on the slug calorimeter are similar for both test conditions. Nozzle catalytic efficiency is inferred to have a Gaussian atomic oxygen recombination efficiency distribution with a mean of 0.027 and a uniform atomic nitrogen recombination efficiency distribution ranging from 0.001 to 1.0. Three-sigma uncertainties for the Gaussian calibration parameters range from a half to full order of magnitude. Calibrated catalytic efficiencies evaluated in this work follow experimental data trends from the literature, which show that the catalytic efficiency is negligibly impacted by surface temperature and follows a logarithmic behavior with respect to surface pressure.