Assessment of Thermochemistry Modeling for Hypersonic Flow over a Double Cone

Holloway, Michael E.; Hanquist, Kyle M.; Boyd, Iain D.

doi:10.2514/1.t5792

Cited by 26 publications

(11 citation statements)

References 17 publications

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“…The results of Holloway et al. (2020) for wall pressure are in very good accordance with the DSMC data, too. However, the first heat flux peak is approximately 14 % lower.…”

Section: Resultssupporting

confidence: 80%

“…Axisymmetric simulations were conducted on a 25 • /55 • double cone geometry. The same configuration has been used in several previous studies (Nompelis et al 2003(Nompelis et al , 2010Moss & Bird 2005;Holloway et al 2020). The conditions in the free stream were selected based on Nompelis et al (2010) and correspond to those in Run 88, as detailed in table 4.…”

Section: Simulation Details: Geometry and Flow Conditionsmentioning

confidence: 99%

“…The physical description of these flows is further complicated by the fact that characteristic fluid time scales approach those of internal energy relaxation and chemical reactions, thus resulting in local thermochemical non-equilibrium. Failure to properly describe the finite rate nature of these processes leads to incorrect numerical predictions (Holloway, Hanquist & Boyd 2020).…”

Section: Introductionmentioning

confidence: 99%

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Near-continuum, hypersonic oxygen flow over a double cone simulated by direct simulation Monte Carlo informed from quantum chemistry

et al. 2023

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A large-scale, fully resolved direct simulation Monte Carlo (DSMC) computation of a non-equilibrium, reactive flow of pure oxygen over a double cone is presented. Under the simulated near-continuum conditions, the computational demands are shown to be significant because of the wide range of length scales that must be resolved. Therefore, robust grid adaption capabilities and efficient parallelization of the Stochastic PArallel Rarefied-gas Time-accurate Analyzer (SPARTA) code that is utilized in this work are essential. The thermochemical and transport collision models were selected for efficiency and simplicity. First-principles data, obtained from the highly accurate direct molecular simulation method, were used to inform the collision models’ parameters. Importantly, because SPARTA implements molecular collision models using collision-specific energies, the resulting macroscopic relaxation rates were evaluated a posteriori via zero-dimensional heat bath simulations. The comparisons of surface properties, namely heat flux and pressure, show very close agreement with previous computational fluid dynamics (CFD) results. Differences with the measurements were found to be similar to the CFD simulations. The unresolved discrepancy with the measurements could be due to inconsistent free stream conditions with the actual experimental data or missing physical phenomena altogether, for example atomic and molecular oxygen electronically excited states, three-dimensional effects, or more complex gas–surface interactions. As shown in this work, the advantages of obtaining a DSMC particle solution for these flows reside in the method's ability to be directly informed from first principles and to seamlessly describe internal energy non-equilibrium for all modes. With the advent of exascale computing and beyond, particle methods will be an increasingly important tool to verify the validity of physical assumptions in reduced-order models via fully resolved, experimental-scale simulations, down to the level of molecular-level distributions.

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“…The results of Holloway et al. (2020) for wall pressure are in very good accordance with the DSMC data, too. However, the first heat flux peak is approximately 14 % lower.…”

Section: Resultssupporting

confidence: 80%

Section: Simulation Details: Geometry and Flow Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Near-continuum, hypersonic oxygen flow over a double cone simulated by direct simulation Monte Carlo informed from quantum chemistry

et al. 2023

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“…This, in turn, affects flow observables, such as UV emissions, as well as surface properties, most notably distributed heat fluxes. Recent computational studies [1] have shown that predicted surface properties, both aerodynamic and thermal, are sensitive to the nonequilibrium thermochemistry modeling. Nonequilibrium gas flows have been the primary scope of several experimental campaigns [2][3][4][5] conducted over the last two decades.…”

Section: Introductionmentioning

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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“…This, in turn, affects flow observables, such as UV emissions, as well as surface properties, such as distributed heat fluxes. It was shown that predicted surface properties, primarily heat flux, are sensitive to the finite-rate chemistry modeling [1] and, to a lesser extent, thermal nonequilibrium modeling [2]. Several experimental campaigns [3][4][5][6] have been conducted over the last two decades to study nonequilibrium flows, aimed at providing surface and flow properties to the modelers, and thus building a reference database for validation of numerical approaches and models.…”

Section: Introductionmentioning

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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Assessment of Thermochemistry Modeling for Hypersonic Flow over a Double Cone

Cited by 26 publications

References 17 publications

Near-continuum, hypersonic oxygen flow over a double cone simulated by direct simulation Monte Carlo informed from quantum chemistry

Near-continuum, hypersonic oxygen flow over a double cone simulated by direct simulation Monte Carlo informed from quantum chemistry

Kinetic and Continuum Modeling of High-Temperature Air Relaxation

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

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