Optical thickness measurements of vacuum ultraviolet radiation in the X2 expansion tube

Sheikh, Umar A., Morgan, Richard G. and McIntyre, Timothy J. (2016) Optical thickness measurements of vacuum ultraviolet radiation in the X2 expansion tube. AIAA Journal, 54 8: 2407-2417. doi:10.2514/1.J054659

Author Sheikh, Umar A.
Morgan, Richard G.
McIntyre, Timothy J.
Title Optical thickness measurements of vacuum ultraviolet radiation in the X2 expansion tube
Journal name AIAA Journal   Check publisher's open access policy
ISSN 1533-385X
Publication date 2016-08-01
Year available 2016
Sub-type Article (original research)
DOI 10.2514/1.J054659
Open Access Status Not yet assessed
Volume 54
Issue 8
Start page 2407
End page 2417
Total pages 11
Place of publication Reston, VA United States
Publisher American Institute of Aeronautics and Astronautics
Language eng
Formatted abstract
Experiments were conducted in the X2 expansion tube to measure vacuum ultraviolet radiation from shock layers representative of reentry conditions at flight equivalent velocities of 10.0 and 12.2  km/s. Cylindrical models of varying lengths were used to make measurements of different depths of radiating gases. Spectral emission measurements were made, imaging parallel to the surface of the models along the stagnation streamline. Ratios of integrated spectral bands were compared to quantify increases in radiance with increasing depth of radiating gas. Significant increases in observed radiance were measured with increasing model length. Comparisons were made with simulations that assumed an optically thin shock layer, and it was found that over 98.9% of the total vacuum ultraviolet radiation emitted was self-absorbed. Good agreement was found between the simulations and measurements of total radiance for the different depths of radiating gas. These results highlight the need to accurately quantify the opacity of a shock layer and spectral line broadening because it significantly increases the radiance emitted from the shock layer in the vacuum ultraviolet region.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
School of Mechanical & Mining Engineering Publications
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