Radiative Transfer in Gases Under Thermal and Chemical Nonequilibrium Conditions: Application to Earth Atmospheric Re-Entry

Lamet, Jean-Michel; Babou, Yacine; Rivière, Philippe; Perrin, Marie‐Yvonne; Soufiani, Anouar

doi:10.1615/ichmt.2007.radtransfproc.180

Cited by 3 publications

(5 citation statements)

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“…Figure 7 shows the calculated results according to these two schemes. The partition functions calculated by Equation (12) have a good agreement with those obtained by Equation (11), which indicates that the computational procedure of nonequilibrium partition function is self-consistent and reliable. The colour maps of nonequilibrium partition functions calculated by the two-temperature model are presented in Figure 8.…”

Section: Resultssupporting

confidence: 65%

“…The accuracy of the partition functions was verified by the results at equilibrium. In order to demonstrate the reliability of the calculation approach for nonequilibrium partition function, we put T r = T v into Equation (12) to calculate the partition function of N 2 and compared the results with the values obtained by Equation (11). Figure 7 shows the calculated results according to these two schemes.…”

Section: Resultsmentioning

confidence: 99%

“…In this case, air plasmas are always in a thermodynamic nonequilibrium state, making it difficult to utilize a single temperature to characterize the thermodynamic properties, such as the most important partition functions. [12,13] Owing to the feasibility of partition functions in computing the level populations, the radiative properties can be evaluated for each component. Therefore, partition functions are necessary and their determination is of great importance for further calculations of radiative properties.…”

Section: Introductionmentioning

confidence: 99%

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Partition functions of atomic and diatomic species in high‐temperature atmospheric plasmas

Liu

2021

Contributions to Plasma Physics

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Accurate atomic and diatomic partition functions are required to determine the level populations for the calculations of radiative properties in thermodynamic equilibrium and nonequilibrium plasmas produced by various atmospheric re-entries. In this work, a reliable partition functions database was rebuilt for some atomic and diatomic species from 100 K to 50000 K. The atomic partition functions were obtained by a four-level model, while the diatomic partition functions were predicted based upon a more rigorous approach for the computation of the energy levels. Compared with previous publications, the number of diatomic electronic states considered in our work is as large as possible. Estimates are made for the contributions of each electronic state of the diatomic molecule to the partition function. Moreover, the effect of the number of electronic states on the partition function was also evaluated. Finally, we calculated the specific heat based upon the obtained partition functions. All the results were validated by the available data in recent references and the relative errors were systematically analysed.

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Section: Resultssupporting

confidence: 65%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Partition functions of atomic and diatomic species in high‐temperature atmospheric plasmas

Liu

2021

Contributions to Plasma Physics

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“…Lamet et al 3,24 have proposed different strategies to evaluate η k σ (s ′ )τ k σ (s ′ , s) ∆σ , depending on the type of contribution k. To begin, the contributions are split into three groups, (i) opticallly thick molecular systems, (ii) optically thin molecular systems and continua, and (iii) atomic lines. The following splitting of the mean intensity is then introduced.…”

Section: The Hybrid Statistical Narrow Band Modelmentioning

confidence: 99%

Coupled Flow, Radiation, and Ablation Simulations of Atmospheric Entry Vehicles using the Hybrid Statistical Narrow Band Model

Scoggins

Soucasse

Rivière

et al. 2015

45th AIAA Thermophysics Conference

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A model for coupled flow, radiation, and ablation calculations along the stagnation lines of atmospheric entry vehicles is developed to study the effects these coupled phenomena have on each other as well as the predicted quantities of interest to vehicle designers. The flow model is based on the two-temperature, multicomponent, reacting Navier-Stokes equations coupled to radiative heat and photochemistry source terms and reduced to onedimension using the dimensionally reduced Navier-Stokes approximation. The radiative source terms are computed using the hybrid statistical narrow band model developed at the EM2C laboratory at Ecole Centrale Paris. This model has previously been shown to accurately produce radiative properties at significantly reduced computational cost when compared to line-by-line calculations for uncoupled flows without ablation. In this work, the hybrid statistical narrow band model is coupled to the one-dimensional stagnation line flow solver with ablation. Ablation is treated through a simple steady-state ablation boundary condition with finite-rate heterogenous reactions capable of simulating ablation products blowing into the boundary layer. The model is first used to simulate the effect of carbonaceous species in a typical boundary layer environment. In particular, it is shown that a boundary layer contaminated with a relatively small amount of ablation and pyrolysis products can have significantly lower transmissivities than a boundary layer with pure air. Finally, the peak heating point for the Apollo 4 command module is analyzed using each of the four possible coupling strategies: flow, flow and ablation, flow and radiation, and fully coupled. It is shown that for this case, radiation coupling is the dominant phenomena due to a relatively small carbon yield in the boundary layer. In addition, comparison of cumulative intensities with the radiometer measurement made during the flight shows excellent agreement and confirms the assumption that the radiometer cavity has little effect on the measured intensity due to the low amount of carbon present in the cavity.

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“…Lamet et al [18] developed a model for radiative transfer in media described by multi-temperatures under chemical nonequilibrium. Lamet et al [19] presented a statistical narrow-band model of radiative properties in nonequilibrium conditions for optically thick molecular electronic systems and combined this model with a box model for optically thin molecular electronic systems and continuum spectra. Bansal et al [20][21][22][23][24] applied the FSK to media at non-LTE conditions.…”

Section: Introductionmentioning

confidence: 99%

Application of approximations for joint cumulative k-distributions for mixtures to FSK radiation heat transfer in multi-component high temperature non-LTE plasmas

Maurente

França

Miki

et al. 2012

Journal of Quantitative Spectroscopy and Radiative Transfer

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Radiative Transfer in Gases Under Thermal and Chemical Nonequilibrium Conditions: Application to Earth Atmospheric Re-Entry

Cited by 3 publications

References 0 publications

Partition functions of atomic and diatomic species in high‐temperature atmospheric plasmas

Partition functions of atomic and diatomic species in high‐temperature atmospheric plasmas

Coupled Flow, Radiation, and Ablation Simulations of Atmospheric Entry Vehicles using the Hybrid Statistical Narrow Band Model

Application of approximations for joint cumulative k-distributions for mixtures to FSK radiation heat transfer in multi-component high temperature non-LTE plasmas

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