This paper reports on the use of spectral techniques for measuring excitation levels of a radiating hypersonic flow undergoing a rapid expansion. The X2 expansion tube, located at The University of Queensland was used to generate a test case physically similar to superorbital flight conditions, where a argon test flow was first processed by an oblique shock and then by an expansion fan. Emission spectroscopy was conducted to determine the populations of electronic energy levels of the argon by measuring electromagnetic radiation intensity at visible and infrared wavelengths. Excitation temperatures were resolved along spatial lines above the model, from upstream of the shock to downstream of the expansion fan. These temperatures were found to increase from 9000 to 10,000 K between the shock and the expansion fan, with the temperature frozen in the expansion fan. Numerical simulations of the flow showed a similar trend, with the computed excitation temperature in the expansion fan also freezing. Shock precursor radiation was also detected, indicating that the excitation temperature upstream of the shock and through the expansion fan is likely to be influenced by radiation from the immediate postshock region.
Emission Spectroscopy of Ionizing Superorbital Expanding Flow
AIAA Journal ; 59 , 8 ; 3217-3227
2021-03-10
11 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
VACUUM ULTRAVIOLET EMISSION SPECTROSCOPY SYSTEM FOR SUPERORBITAL RE-ENTRIES
British Library Conference Proceedings | 2012
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