Equilibrium radiation from isothermal hydrogen-helium plasmas

Nelson, H. F.; Goulard, R.

doi:10.1016/0022-4073(68)90079-4

Cited by 18 publications

(1 citation statement)

References 14 publications

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“…Analyses of radiating flowfields present in the aerothermodynamics literature do not typically account for the lowering of the ionization potential, with only a few exceptions. 135,136 To illustrate the approximate influence of ionization potential lowering on a high-speed Earth entry shock layer, the equilibrium conditions behind a normal shock moving at range of velocities and a density of 3×10 −4 kg/m 3 are considered. The percent difference in the post-shock temperature and electron number density due to ionization potential lowering are shown in Fig.…”

Section: Lowering Of the Ionization Potentialmentioning

confidence: 99%

Assessment of Radiative Heating Uncertainty for Hyperbolic Earth Entry

Johnston

Mazaheri

Gnoffo

et al. 2011

42nd AIAA Thermophysics Conference

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This paper investigates the shock-layer radiative heating uncertainty for hyperbolic Earth entry, with the main focus being a Mars return. In Part I of this work, a baseline simulation approach involving the LAURA Navier-Stokes code with coupled ablation and radiation is presented, with the HARA radiation code being used for the radiation predictions. Flight cases representative of peak-heating Mars or asteroid return are defined and the strong influence of coupled ablation and radiation on their aerothermodynamic environments are shown. Structural uncertainties inherent in the baseline simulations are identified, with turbulence modeling, precursor absorption, grid convergence, and radiation transport uncertainties combining for a +34% and −24% structural uncertainty on the radiative heating. A parametric uncertainty analysis, which assumes interval uncertainties, is presented. This analysis accounts for uncertainties in the radiation models as well as heat of formation uncertainties in the flowfield model. Discussions and references are provided to support the uncertainty range chosen for each parameter. A parametric uncertainty of +47.3% and −28.3% is computed for the stagnation-point radiative heating for the 15 km/s Mars-return case. A breakdown of the largest individual uncertainty contributors is presented, which includes C3 Swings cross-section, photoionization edge shift, and Opacity Project atomic lines. Combining the structural and parametric uncertainty components results in a total uncertainty of +81.3% and −52.3% for the Mars-return case.In Part II, the computational technique and uncertainty analysis presented in Part I are applied to 1960s era shock-tube and constricted-arc experimental cases. It is shown that experiments contain shock layer temperatures and radiative flux values relevant to the Mars-return cases of present interest. Comparisons between the predictions and measurements, accounting for the uncertainty in both, are made for a range of experiments. A measure of comparison quality is defined, which consists of the percent overlap of the predicted uncertainty bar with the corresponding measurement uncertainty bar.

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Section: Lowering Of the Ionization Potentialmentioning

confidence: 99%