Hypersonic Aerothermodynamics: Past, Present and Future

Park, Chul

doi:10.5139/ijass.2013.14.1.1

Cited by 17 publications

(4 citation statements)

References 19 publications

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“…Because of the incomplete thermalization of the vibrational ladder, the dissociation rate during the QSS phase is lower than that estimated at thermally equilibrium conditions. The ratio of equilibrium and QSS rate coefficients is approximately 3 according to Park [28]; however, for O 2 -O, this ratio is found to increase rapidly at high temperature due to inefficient vibrational relaxation at these conditions. The QSS rate coefficients can be derived from the complete set of bound-bound and bound-free transition rate coefficients by solving the system of master equations with the additional constraint of ∂n v ∕∂t 0.…”

Section: Qss Dissociation Rate Coefficientmentioning

confidence: 97%

Aerothermochemical Nonequilibrium Modeling for Oxygen Flows

Neitzel

Andrienko

Boyd

2017

Journal of Thermophysics and Heat Transfer

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The results from a set of vibrational nonequilibrium models with a range of fidelity are compared to the recent experimental data for several postnormal shock test cases. The present work focuses solely on oxygen flows with an emphasis on implementing a new set of accurate state-specific rate coefficients for O 2-O collisions. The twotemperature model is presented as the computationally efficient, lower-fidelity approach in this work. The twotemperature model is driven by the relaxation parameters based on the Millikan-White empirical equation as well as on the parameters resulting from a master equation simulation that employs the database of state-resolved O 2-O rate coefficients. The full state-to-state master equation approach is presented as the higher-fidelity modeling approach. The O 2-O system uses recently available results of trajectory simulations for state-specific transition rate coefficients The O 2-O 2 system uses transition rates from the forced harmonic oscillator model. The test case comparison shows that the state-resolved modeling approach is more suitable for describing the vibrational temperature and chemically nonequilibrium zone behind the shock wave. It is shown that the capability of the state-resolved model to capture non-Boltzmann distribution is critical for accurately modeling the vibrational relaxation and dissociation phase.

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Section: Qss Dissociation Rate Coefficientmentioning

confidence: 97%

Aerothermochemical Nonequilibrium Modeling for Oxygen Flows

Neitzel

Andrienko

Boyd

2017

Journal of Thermophysics and Heat Transfer

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“…Further, at certain reentry conditions radiative transfer can contribute both to the surface heat fluxes and to the cooling of the shock and boundary layers surrounding the vehicle depending on the spectral emission and absorption properties of the surrounding molecules [5,6]. Computational Fluid Dynamics (CFD) through a coupled modeling of nonequilibrium, reacting flows with radiative heat transfer can yield valuable insights into the flow characteristics within these hypersonic flight environments [7,8]. However, due to the fact that radiative heat transfer calculations are inherently expensive as a result of its strong spatial, directional, and wave-length dependencies [9,10], the radiation field is often computed in a 1D domain.…”

Section: Introductionmentioning

confidence: 99%

Computationally Efficient Assessments of the Effects of Radiative Transfer, Turbulence Radiation Interactions, and Finite Rate Chemistry in the Mach 20 Reentry F Flight Vehicle

Krishnamoorthy

Clarke

2016

Journal of Computational Engineering

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Effects of finite rate chemistry, radiative heat transfer, and turbulence radiation interactions (TRI) are assessed in a fully coupled manner in simulations of the Mach 20 Reentry F flight vehicle. Add-on functions were employed to compute a Planck mean absorption coefficient and the temperature self-correlation term (for TRI effects) in the optically thin shock layer. Transition onset was induced by specifying a wall roughness height at the experimentally observed transition location. The chemistry was modeled employing eight elementary reactions and an equilibrium approach allowing species to relax towards their chemical equilibrium values over the process characteristic time scale. The wall heat fluxes in the turbulent region, density, and velocity profiles compared reasonably well against measurements as well as similar calculations reported previously. The density predictions were more sensitive to the choice of modeling options than the velocities. The radiative source term magnitude agreed closely with its measurements deduced from shock tube experiments. The TRI model predicted a 60% enhancement in emission due to temperature fluctuations in the turbulent boundary layer. While the variations in density and velocity predictions among the models diminished along the length of the body, the O and NO prediction variations extended well into the turbulent boundary layer.

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“…Once these aerodynamic forces and thrust are known, the nonlinear model of hypersonic vehicle is demonstrated as follows: [4,25] …”

Section: Dynamic Modeling Using Multidisciplinary Knowledge Of Hypersmentioning

confidence: 99%

“…Compared with conventional vehicles, hypersonic vehicles exhibit unique wave-riding features and operate with high dynamic pressure in uncertain and unknown environments [4]. In addition to the dynamic complexity and unexpected coupling between the airframe and the propulsion system, physical limitations on the control inputs presents numerous challenges for the implementation of continuous control throughout a large flight envelope.…”

Section: Introductionmentioning

confidence: 99%

Compromise Optimal Design using Control-based Analysis of Hypersonic Vehicles

Liu¹,

Hua²

2015

International Journal of Aeronautical and Space Sciences

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Hypersonic vehicles exhibit distinct dynamic and static characteristics, such as unstable dynamics, strict altitude angle limitation, large control bandwidth, and unconventional system sensitivity. In this study, compromise relations between the dynamic features and static performances for hypersonic vehicles are investigated. A compromise optimal design for hypersonic vehicles is discussed. A parametric model for analyzing the dynamic and static characteristics is established, and then the optimal performance indices are provided according to the different design goals. A compromise optimization method to balance the dynamic and static characteristics is also discussed. The feasibility of this method for hypersonic vehicles is demonstrated.

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Hypersonic Aerothermodynamics: Past, Present and Future

Cited by 17 publications

References 19 publications

Aerothermochemical Nonequilibrium Modeling for Oxygen Flows

Aerothermochemical Nonequilibrium Modeling for Oxygen Flows

Computationally Efficient Assessments of the Effects of Radiative Transfer, Turbulence Radiation Interactions, and Finite Rate Chemistry in the Mach 20 Reentry F Flight Vehicle

Compromise Optimal Design using Control-based Analysis of Hypersonic Vehicles

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