Uncertainty quantification in the rebuilding free-stream temperature inside the VKI Plasmatron

Abstract

The VKI Plasmatron is a plasma wind tunnel that allow the reproduction of some of the conditions of an atmospheric reentry. A plasma is generated at low subsonic regime at temperatures up to about 10000 K. This temperature is measured by optical emission spectroscopy. More specifically, the procedure focused on the atomic emission of the oxygen and nitrogen lines at 777 nm and 747 nm respectively. In the measurement procedure, many parameters have uncertainties that lead to an error on the temperature computation. In this thesis, the uncertainties on eight parameters are quantified. These uncertainties are then propagated through the measurement chain by the Monte Carlo propagation method. In this case, the propagated uncertainties will depend on the emission line used to retrieve the temperature, so both computations are performed and compared. Each source of uncertainty is also propagated individually to be compared with each other.