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Measurements of Time-Resolved Air Freestream Nitric Oxide Rotational, Vibrational Temperature and Concentration in the T5 Reflected Shock Tunnel

Finch, Peter M. and Girard, Julian and Strand, Chris and Yu, Wesley and Austin, Joanna and Hornung, Hans and Hanson, Ronald (2020) Measurements of Time-Resolved Air Freestream Nitric Oxide Rotational, Vibrational Temperature and Concentration in the T5 Reflected Shock Tunnel. In: AIAA Propulsion and Energy 2020 Forum. American Institute of Aeronautics and Astronautics , Reston, VA, Art. No. 2020-3714. ISBN 978-1-62410-602-6. https://resolver.caltech.edu/CaltechAUTHORS:20200819-133135092

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Abstract

We report on measurements of freestream temperature and nitric oxide (NO) collected in the Caltech T5 reflected shock tunnel facility. Quantum cascade lasers (QCL), emitting mid-infrared light resonant with fundamental rovibrational NO transitions, were directed through the supersonic (Mach ~5) flow immediately downstream of the nozzle exit plane. Tunable diode laser absorption spectroscopy (TDLAS) was used to measure the path-averaged rotational and vibrational temperature 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 test-period (from 1 to 2 ms after shock reflection). Agreement between vibrational and rotational temperature was observed in all experiments, including one lower-enthalpy (h₀,∞ ≈ 8 MJ/kg) and four higher-enthalpy (h₀,∞ ≈ 18 MJ/kg) shots, during and after the nominal test time. Slight disagreement between the rotational and vibrational temperatures was observed during the start-up period preceding the test time. Unexpected absorption from CO and H₂O was also observed in the TDLAS measurements, yielding estimates of their partial pressures in the flow. The goal of these and future experiments is to help to inform improvements of existing models and solvers used for prediction of freestream conditions. Future efforts will include a more quantitative evaluation of freestream conditions, including core flow velocity and uniformity, and TDLAS measurements near relevant flow models.


Item Type:Book Section
Related URLs:
URLURL TypeDescription
https://doi.org/10.2514/6.2020-3714DOIArticle
ORCID:
AuthorORCID
Hornung, Hans0000-0002-4903-8419
Additional Information:© 2020 American Institute of Aeronautics and Astronautics. Published Online: 17 Aug 2020.
Group:GALCIT
Other Numbering System:
Other Numbering System NameOther Numbering System ID
AIAA Paper2020-3714
Record Number:CaltechAUTHORS:20200819-133135092
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200819-133135092
Official Citation:Measurements of Time-Resolved Air Freestream Nitric Oxide Rotational, Vibrational Temperature and Concentration in the T5 Reflected Shock Tunnel. Peter M. Finch, Julian Girard, Chris Strand, Wesley Yu, Joana Austin, Hans Hornung, and Ronald Hanson. AIAA Propulsion and Energy 2020 Forum. August 2020; doi: 10.2514/6.2020-3714
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:105034
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:19 Aug 2020 20:45
Last Modified:19 Aug 2020 20:45

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