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Measurements of Reflected Shock Tunnel Freestream Nitric Oxide Temperatures and Partial Pressure

Girard, Julian J. and Finch, Peter M. and Strand, Christopher L. and Hanson, Ronald K. and Yu, Wesley M. and Austin, Joanna M. and Hornung, Hans G. (2021) Measurements of Reflected Shock Tunnel Freestream Nitric Oxide Temperatures and Partial Pressure. AIAA Journal . ISSN 0001-1452. doi:10.2514/1.j060596. (In Press)

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This paper reports on measurements of freestream nitric oxide (NO) rotational and vibrational temperatures and partial pressures, collected in the Caltech T5 reflected shock tunnel. Quantum cascade lasers, emitting mid-infrared light resonant with fundamental rovibrational NO transitions, were directed through the supersonic (Mach ∼5) freestream flow. Tunable diode laser absorption spectroscopy (TDLAS) was used to measure the path-averaged rotational and vibrational temperatures of NO in the flow, in addition to the NO partial pressure. The temperature measurements demonstrate strong evidence of NO rotational and vibrational equilibrium during the 1 ms test period. Agreement between vibrational and rotational temperatures was observed in all experiments, including one h₀,∞≈8  MJ/kg and four h₀,∞≍18  MJ/kg experiments, during and after the nominal test time. Absorption from CO and H₂O was also observed in the TDLAS measurements, though their concentrations cannot be accurately estimated. The goal of these and future experiments is to develop and demonstrate TDLAS experimental strategies for high-enthalpy impulse facilities and to help to inform improvements of existing models and solvers used for prediction of freestream conditions.

Item Type:Article
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URLURL TypeDescription
Strand, Christopher L.0000-0002-4112-6668
Hanson, Ronald K.0000-0002-8030-5327
Austin, Joanna M.0000-0003-3129-5035
Hornung, Hans G.0000-0002-4903-8419
Additional Information:© 2021 by Julian Girard. Published by the American Institute of Aeronautics and Astronautics, Inc. Published Online: 9 Aug 2021. Presented as Paper 2020-3714 at the 2020 AIAA Propulsion Energy Forum, Virtual, August 24–26, 2020; received 29 January 2021; revision received 7 May 2021; accepted for publication 20 May 2021; published online 6 August 2021. This work was supported by the Air Force Office of Scientific Research (AFOSR) through grant number FA9550-19-1-0219, with Ivett Leyva and Sarah Popkin as contract monitors.We would like to acknowledge the help of Bahram Valiferdowsi in running the experiments.
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Air Force Office of Scientific Research (AFOSR)FA9550-19-1-0219
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AIAA Paper2020-3714
Record Number:CaltechAUTHORS:20210910-224532781
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:110817
Deposited By: Tony Diaz
Deposited On:13 Sep 2021 17:42
Last Modified:13 Sep 2021 17:42

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