Abstract
Tunable Diode Laser Absorption Spectroscopy (TDLAS) measurements of nitric oxide (NO) using a Quantum Cascade Laser (QCL) in the vicinity of 5.26 μm were conducted in a hypervelocity flow generated in the Texas A&M Hypervelocity Expansion Tunnel (HXT). The nascent NO was produced downstream of symmetric Mach reflections generated in Mach 8.5 flows with stagnation enthalpies from 6.9 to 11.1 MJ/kg. Path-averaged flow parameters of rotational and vibrational temperatures and NO concentration at a measurement rate of 30 kHz were obtained. By probing the R-branch of the fundamental absorption band in NO, thermal nonequilibrium and NO concentration levels in the post-shock region were measured. Measurements are compared to equilibrium calculations. NO equilibrium values during the 1 ms test period differ from the experimental rotational and vibrational measurements across the same time period. The experimental measurements of the rotational temperature show a consistent value around 3000 K larger than the recovered vibrational temperature across any run. The NO concentrations in all runs are near to the reported equilibrium value; often beginning higher than, and over time decaying to, the equilibrium concentration value of the specific tunnel run.
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Abbreviations
- \(A\) :
-
Einstein A-coefficient
- \(\widetilde{A}\) :
-
1st spin-splitting energy term
- \({B}_{\text{v}}\) :
-
Rotational constant for vibronic level
- \(C\) :
-
2nd spin-splitting term
- \(c\) :
-
Speed of light
- \({c}_{x}\) :
-
Constant of x broadening
- \({c}_{2}\) :
-
2nd radiation constant
- \({D}_{v}\) :
-
Centrifugal stretching term for the vibronic level \(v\)
- \(d\) :
-
Lorentzian–Gaussian ratio
- \({F}^{{\prime}{\prime}}\) :
-
Lower-state rotational energy
- \({f}_{V}\) :
-
Voigt convolution function
- \({G}^{{\prime}{\prime}}\) :
-
Lower-state vibrational energy
- \({g}_{V}\) :
-
Voigt convolution function
- \(h\) :
-
Planck constant
- \(I\) :
-
Moment of inertia
- \({I}_{\text{t}}\) :
-
Transmitted signal
- \({I}_{0}\) :
-
Baseline signal
- \(J\) :
-
Rotational quantum number
- \({k}_{B}\) :
-
Boltzmann constant
- \(L\) :
-
Laser pathlength
- \(M\) :
-
Molecular weight
- \({M}_{a}\) :
-
Mach number
- \(m\) :
-
Mass
- \({N}_{A}\) :
-
Avogadro constant
- \(n\) :
-
Molecular density
- \({n}_{air}\) :
-
Temperature dependence coefficient
- \(P\) :
-
Pressure
- \(\widetilde{P}\) :
-
Constant in the expression for \(\Lambda\)-doubling
- \(Q\) :
-
Molecular partition function
- \(\widetilde{Q}\) :
-
Constant in the expression for \(\Lambda\)-doubling
- \({r}_{0}\) :
-
Molecular distance between two atoms of a diatomic molecule
- \(S\) :
-
Linestrength intensity
- \({T}_{x}\) :
-
Temperature of \(x\) mode excitation
- \({T}_{\infty }\) :
-
Freestream temperature
- \(t\) :
-
Time
- \(v\) :
-
Vibrational quantum number
- \({Y}_{v}\) :
-
Term in the ground electronic state rotational energy
- \(\alpha\) :
-
Absorbance
- \({\alpha }_{x}\) :
-
Broadening due to x
- \(\gamma\) :
-
Heat capacity ratio
- \({\gamma }_{x}\) :
-
x-broadened HWHM
- \(\widetilde{\gamma }\) :
-
Spin-splitting term for the excited state
- \(\Delta F\) :
-
Change in rotational energy
- \(\Delta f\) :
-
Optical linewidth
- \(\Delta G\) :
-
Change in vibrational energy
- \({\theta }_{x}\) :
-
Characteristic temperature of x mode excitation
- \(\lambda\) :
-
Wavelength
- \(\mu\) :
-
Ratio of NO vibronic constants
- \(\nu\) :
-
Wavenumber
- \(\xi\) :
-
Average noise uncertainty
- \(\sigma\) :
-
Absorption cross section
- \(\tau\) :
-
Transmission
- \(\phi\) :
-
Hyperfine transition term
- \(\chi\) :
-
Mole fraction
- \({\omega }_{e}\) :
-
1st harmonic oscillator vibrational constant
- \({\omega }_{e}{x}_{e}\) :
-
Anharmonicity constant
- \(\tilde\omega\) :
-
Term in the calculation of rotational energy
References
Bond, Ryan B., Kenneth Tatum, Greg D. Power, and Todd Tuckey. n.d. “Capabilities of HPCMP CREATE-AV Kestrel V11 for Hypersonic flight and ground testing with a two-temperature model.” In AIAA scitech 2021 forum. American institute of aeronautics and astronautics. Accessed May 24, 2023. https://doi.org/10.2514/6.2021-0236
Bryan, Caleb A., Tyler Dean, Bryan J. Morreale, and Rodney D. Bowersox (2023) “Computational simulations of hypersonic mach stems at high enthalpy.” In AIAA SCITECH 2023 forum. National harbor, MD and Online: american institute of aeronautics and astronautics. https://doi.org/10.2514/6.2023-0858
Chang LS, Strand CL, Jeffries JB, Hanson RK, Diskin GS, Gaffney RL, Capriotti DP (2011) Supersonic mass-flux measurements via tunable diode laser absorption and nonuniform flow modeling. AIAA J 49(12):2783–2791. https://doi.org/10.2514/1.J051118
Chase, MW Jr. n. d. NIST-JANAF Thermochemical tables, Monograph 9. Fourth. Vol. 9. Washington DC: American chemical society. http://www.nist.gov/srd/monogr.cfm
Dean T, Blair TR, Roberts M, Limbach C, Bowersox RD n.d. “On the initial characterization of a large-scale hypervelocity expansion tunnel.” In AIAA SCITECH 2022 Forum. American institute of aeronautics and astronautics. Accessed May 24, 2023. https://doi.org/10.2514/6.2022-1602.
Dean T, Blair TR, Roberts M, Limbach C, Bowersox RD (2023) “Index of refraction fluctuation spectra in aerothermochemical non-equilibrium shock layers.” In AIAA SCITECH 2023 forum. AIAA SciTech Forum. American institute of aeronautics and astronautics. https://doi.org/10.2514/6.2023-0270
Finch PM, Girard J, Strand C, Yu W, Austin J, Hornung H, Hanson R n.d. “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. Accessed October 6, 2023. https://doi.org/10.2514/6.2020-3714
Girard JJ, Finch PM, Strand CL, Hanson RK, Yu WM, Austin JM, Hornung HG (2021) Measurements of reflected shock tunnel freestream nitric oxide temperatures and partial pressure. AIAA J 59(12):5266–5275. https://doi.org/10.2514/1.J060596
Gordon IE, Rothman LS, Hargreaves RJ, Hashemi R, Karlovets EV, Skinner FM, Conway EK et al (2022) The HITRAN2020 Molecular spectroscopic database. J Quant Spectrosc Radiat Transfer 277:107949. https://doi.org/10.1016/j.jqsrt.2021.107949
Hanson RK, Mitchell Spearrin R, Goldenstein CS (2016) Spectroscopy and optical diagnostics for gases. Springer International Publishing, Cham. https://doi.org/10.1007/978-3-319-23252-2
Liu Y, Lin J, Huang G, Guo Y, Duan C (2001) Simple empirical analytical approximation to the voigt profile. J Opt Soc Am B 18(5):666. https://doi.org/10.1364/JOSAB.18.000666
Park C (1989) Assessment of two-temperature kinetic model for ionizing air. J Thermophys Heat Transfer 3(3):233–244. https://doi.org/10.2514/3.28771
Parker, Ronald, Thomas Wakeman, Michael Holden, and Matthew MacLean (2006) “Measuring nitric oxide freestream concentration using quantum cascade lasers at CUBRC”. In 44th AIAA Aerospace sciences meeting and exhibit. Aerospace sciences meetings. American institute of aeronautics and astronautics. https://doi.org/10.2514/6.2006-926
Passiatore D, Sciacovelli L, Cinnella P, Pascazio G (2022) Thermochemical non-equilibrium effects in turbulent hypersonic boundary layers. J Fluid Mech 941:A21. https://doi.org/10.1017/jfm.2022.283
Reisel JR, Carter CD, Laurendeau NM (1992) Einstein coefficients for rotational lines of the (0, 0) band of the NO A2Σ+−X2π System. J Quant Spectrosc Radiat Transfer 47(1):43–54. https://doi.org/10.1016/0022-4073(92)90078-I
Schultz IA, Goldenstein CS, Strand CL, Jeffries JB, Hanson RK, Goyne CP (2014) “Hypersonic scramjet testing via TDLAS measurements of temperature and column density in a reflected shock tunnel”. In 52nd Aerospace sciences meeting. National harbor, Maryland: American institute of aeronautics and astronautics. https://doi.org/10.2514/6.2014-0389.
Sweetland K, Combs CS, Schmisseur JD, Rhodes R, Zhang FY, Moeller TM, Plemmons DH (2018). “Development of MIR TLAS System with Applications to Reacting Hot Gas Flows.” In 2018 AIAA Aerospace sciences meeting. Kissimmee, Florida: American institute of aeronautics and astronautics. https://doi.org/10.2514/6.2018-1023
Wada Y, Ogawa S, Kubota H (1993) Thermo-chemical models for hypersonic flows. Comput Fluids 22(2):179–187. https://doi.org/10.1016/0045-7930(93)90049-F
Wehe S, Baer D, Hanson R, Wehe S, Baer D, Hanson R (1997) “Tunable diode-laser absorption measurements of temperature, velocity, and H2O in hypervelocity flows.” In 33rd Joint propulsion conference and exhibit. seattle,WA,U.S.A.: American institute of aeronautics and astronautics. https://doi.org/10.2514/6.1997-3267
Weisberger JM, DesJardin P, MacLean MG, Parker RA, Carr ZR (2016) “Near-surface CO2 tunable diode laser absorption spectroscopy concentration measurements in the LENS-XX expansion tunnel facility.” In 54th AIAA aerospace sciences meeting. San Diego, California, USA: American institute of aeronautics and astronautics. https://doi.org/10.2514/6.2016-0246
Zander F, Molder S, Morgan R, Jacobs P, Gollan R (2012) “High temperature gas effects for converging conical shocks”. In 18th AIAA/3AF international space planes and hypersonic systems and technologies conference. Tours, France: American institute of aeronautics and astronautics. https://doi.org/10.2514/6.2012-5939
Funding
The authors gratefully acknowledge the Office of the Under Secretary of Defense Vannevar Bush Faculty Fellowship program (Drs. B. Nair and J. Cambier, N00014-18–1-3020) for sponsoring a portion of this study. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the Department of Defense. The authors also acknowledge support from the National Science Foundation under NSF-2026242 and the DOE under DE-SC0021382.
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S.F. assisted in the performance of the experiment, wrote the main manuscript text, partially created figure 2 and created figures 4-16, created Tables 3-5, and created the main model used in the research analysis. Z.Z. assisted in the performance of the experiment, assisted in the creation of the model, and reviewed the manuscript. T.D. assisted in the performance of the experiment, partially created figures 2 and 3 and created figure 1, created Tables 1 and 2, and reviewed the manuscript. R.B. assisted in the performance of the experiment and reviewed the manuscript. F.S. assisted in the performance of the experiment, assisted in the creation of the model, and reviewed the manuscript. M.G. assisted in the performance of the experiment, wrote portions of the manuscript text, partially created figure 3, assisted in the creation of the model as well as the frozen temperature analysis, and reviewed the manuscript.
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Feltis, S.E., Zhang, Z., Dean, T.S. et al. Measurements of no rotational and vibrational temperatures behind a normal shock in hypervelocity flow via absorption spectroscopy. Exp Fluids 65, 112 (2024). https://doi.org/10.1007/s00348-024-03841-w
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DOI: https://doi.org/10.1007/s00348-024-03841-w