Improved Analysis of O2 Ultraviolet Absorption Spectra Under Nonequilibrium Shock Conditions

Gimelshein, S. F.; Wysong, Ingrid J.; Bykova, N. G.; Shatalov, O. P.; Забелинский, И. Е.

doi:10.2514/1.j058961

Cited by 9 publications

(2 citation statements)

References 27 publications

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“…[12], is visibly slower than in the experiment; it is not currently clear why there is such a difference. Our earlier comparison [85] of T vib O 2 with measurements [5] has demonstrated that it is beneficial to compare not only vibrational temperatures, but also absorbance traces. This has also been done in this work, with the measured versus computed absorbance versus time dependence shown in Fig.…”

Section: Moderate-temperature Regimementioning

confidence: 99%

Kinetic and Continuum Modeling of High-Temperature Air Relaxation

Gimelshein¹,

Wysong²,

Fangman³

et al. 2022

Journal of Thermophysics and Heat Transfer

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Fully kinetic, vibrationally kinetic, and continuum solvers with varying model fidelity are used in this work to model the high-temperature relaxation of air in 7230 and 15,000 K adiabatic heat baths and a 6 km∕s hypersonic flow over a cylinder. The results show significant impact of uncertainties in vibrational relaxation times and reaction rate constants on thermal and chemical relaxation, in particular, on gas temperature and species mole fractions. Most notably, these uncertainties need to be reduced for collisions that include nitric oxide. Order-of-magnitude differences in the nitric oxide dissociation and recombination rates have a large impact on the peak NO mole fraction immediately behind the shock and surface-distributed heat flux, respectively. High-fidelity kinetic and continuum approaches are found to have different reaction channels having the largest effect on species mole fractions and gas temperature: N 2 O exchange and O 2 O dissociation in the former, and NO O and O 2 N 2 dissociation in the latter.

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Section: Moderate-temperature Regimementioning

confidence: 99%

Kinetic and Continuum Modeling of High-Temperature Air Relaxation

Gimelshein¹,

Wysong²,

Fangman³

et al. 2022

Journal of Thermophysics and Heat Transfer

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“…For nitrogen, the authors are not aware of such data; for oxygen, there are incident shock wave experiments [6] and reflected shock wave experiments [14] for oxygen-argon mixtures. For incident shock waves, in particular, it was found [91,92] that modern absorption diagnostics [6] may not offer sufficient resolution to distinguish between low-and high-fidelity models for shock velocities below 4.5 km/s. For reflected shock waves, accurate capturing of time-resolved interactions of an incident shock with the wall is necessary [93], thus requiring a modification in the numerical algorithm such as that proposed for the DSMC method [93].…”

Section: D and 1d Relaxation With Qct-and Data-based Ratesmentioning

confidence: 99%

Kinetic and Continuum Modeling of High-Temperature Oxygen and Nitrogen Binary Mixtures

Gimelshein¹,

Wysong²,

Fangman³

et al. 2022

Journal of Thermophysics and Heat Transfer

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The present paper provides a comprehensive comparative analysis of thermochemistry models of various fidelity levels developed in leading research groups around the world. Fully kinetic, hybrid kinetic-continuum, and fully continuum approaches are applied to analyze parameters of hypersonic flows starting from the revision of single-temperature rate constants up to the application in 1D post-shock conditions. Comparison of state-specific and twotemperature approaches show there are very significant and often qualitative differences in the time-dependent nonequilibrium reaction rates and their ratio to the corresponding singletemperature rates. A major impact of the vibration-dissociation coupling on the temporal relaxation of gas properties is shown. For instance, the legacy Park's model has a strongly nonlinear behavior of nonequilibrium reaction rate with vibrational temperature, while a nearly linear shape exists for all state-specific approaches. Analysis of vibrational level populations in the nonequilibrium region show a profound impact of the numerical approach and the model on the population ratios, and thus vibrational temperatures inferred from such ratios. The difference in the UV absorption coefficients, calculated by a temperature-based spectral code using vibrational populations from state-specific and kinetic approaches, is found to exceed an

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Direct molecular simulation of oxygen dissociation across normal shocks

Torres

Schwartzentruber

2022

Theor. Comput. Fluid Dyn.

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Improved Analysis of O2 Ultraviolet Absorption Spectra Under Nonequilibrium Shock Conditions

Cited by 9 publications

References 27 publications

Kinetic and Continuum Modeling of High-Temperature Air Relaxation

Kinetic and Continuum Modeling of High-Temperature Air Relaxation

Kinetic and Continuum Modeling of High-Temperature Oxygen and Nitrogen Binary Mixtures

Direct molecular simulation of oxygen dissociation across normal shocks

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