Flow-radiation coupling in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>CO</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>hypersonic wakes using reduced-order non-Boltzmann models

Sahai, Amal; Johnston, Christopher O.; López, Bruno; Panesi, Marco

doi:10.1103/physrevfluids.4.093401

Cited by 37 publications

(7 citation statements)

References 51 publications

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“…During the last decade, many studies of high temperature non-equilibrium CO 2 flows have been carried out using several approaches of various complexity: multi-temperature [47,[339][340][341][342][343], STS [46,[273][274][275][276] and reduced order coarse-graining techniques [344][345][346]. Different effects are discussed such as the influence of the flow conditions, thermo-chemical model, models for transport properties and radiation.…”

Section: Vibrational Kinetics In Hypersonic Entry Problems 71 General Considerationsmentioning

confidence: 99%

Advances in non-equilibrium $$\hbox {CO}_2$$ plasma kinetics: a theoretical and experimental review

et al. 2021

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Numerous applications have required the study of CO2 plasmas since the 1960s, from CO2 lasers to spacecraft heat shields. However, in recent years, intense research activities on the subject have restarted because of environmental problems associated with CO2 emissions. The present review provides a synthesis of the current state of knowledge on the physical chemistry of cold CO2 plasmas. In particular, the different modeling approaches implemented to address specific aspects of CO2 plasmas are presented. Throughout the paper, the importance of conducting joint experimental, theoretical and modeling studies to elucidate the complex couplings at play in CO2 plasmas is emphasized. Therefore, the experimental data that are likely to bring relevant constraints to the different modeling approaches are first reviewed. Second, the calculation of some key elementary processes obtained with semi-empirical, classical and quantum methods is presented. In order to describe the electron kinetics, the latest coherent sets of cross section satisfying the constraints of "electron swarm" analyses are introduced, and the need for self-consistent calculations for determining accurate electron energy distribution function (EEDF) is evidenced. The main findings of the latest zero-dimensional (0D) global models about the complex chemistry of CO2 and its dissociation products in different plasma discharges are then given, and full state-to-state (STS) models of only the vibrational-dissociation kinetics developed for studies of spacecraft shields are described. Finally, two important points for all applications using CO2 containing plasma are discussed: the role of surfaces in contact with the plasma, and the need for 2D/3D models to capture the main features of complex reactor geometries including effects induced by fluid dynamics on the plasma properties. In addition to bringing together the latest advances in the description of CO2 non-equilibrium plasmas, the results presented here also highlight the fundamental data that are still missing and the possible routes that still need to be investigated.

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Section: Vibrational Kinetics In Hypersonic Entry Problems 71 General Considerationsmentioning

confidence: 99%

Advances in non-equilibrium $$\hbox {CO}_2$$ plasma kinetics: a theoretical and experimental review

et al. 2021

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“…It is also well established, from ab-intio based calculations, that a significant amount of post-shock dissociation can occur before the gas reaches QSS 19 , particularly for extreme flight conditions such as atmospheric re-entry. Figure 5 shows the evolution of vibrational energy distributions corresponding to rapid rovibrational excitation of nitrogen gas, starting from T v = 3,000 K and rising towards a fixed translational temperature of T = 20,000 K. The data (symbols in Fig.…”

Section: Generalized Non-boltzmann Rate Expressionmentioning

confidence: 99%

Section: Generalized Non-boltzmann Rate Expressionmentioning

confidence: 99%

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Consistent Kinetic And Continuum Dissociation Models For High-Temperature Air

Singh

Schwartzentruber

2020

AIAA Scitech 2020 Forum

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In this article, we propose a generalized non-equilibrium chemical kinetics model from ab initio simulation data obtained using accurate potential energy surfaces developed recently for the purpose of studying high-temperature air chemistry. First, we present a simple cross-section model for dissociation that captures recent ab initio data accurately. The cross-section model is analytically integrated over Boltzmann distributions and general non-Boltzmann distributions to derive general non-equilibrium dissociation model. The general non-Boltzmann model systematically incorporates key physics such as dependence on translational energy, rotational energy, vibrational energy, internal energy, centrifugal barrier and non-Boltzmann effects such as overpopulation and depletion of high energy states. The model is shown to reproduce the rates from QCT for Boltzmann distributions of internal energy states. Reduced rates in non-equilibrium steady state due to depletion of high internal energy states are also predicted well by the model. Furthermore, the model predicts the enhanced rates as observed due to significant overpopulation of high vibrational states relative to Boltzmann distributions while the gas is in non-equilibrium in the transient phase. The model provides a computationally inexpensive way of incorporating non-equilibrium chemistry without incurring additional cost in the existing computational tools. Further comparisons of the model are carried out in another article, where simplifications to the model are proposed based on the results.

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“…Therefore, compared with the conventional thermochemical non-equilibrium models, the collisional-radiative model can more reasonably predict the energy relaxation processes, chemical non-equilibrium and excited energy levels non-equilibrium phenomena. At present, the collisional-radiative model is usually implemented in zero-dimensional (0-D) (Teulet, Sarrette & Gomes 2001;Bultel et al 2006;Capitelli et al 2007;Annaloro & Bultel 2014) and one-dimensional (1-D) models (Panesi et al 2009;Campoli et al 2020;Du et al 2022), but has not been used in multi-dimensional flow calculations so far due to its intensive computational cost, and some simplification methods, such as the multi-group maximum entropy method, were proposed for simplifying the CR model for future coupling to multi-dimensional computational fluid dynamics (CFD) simulation (Liu et al 2015;Munafo, Liu & Panesi 2015;Munafo, Mansour & Panesi 2017;Sahai et al 2017Sahai et al , 2019Sahai et al , 2020Sharma, Liu & Panesi 2020). The 0-D calculations of the air collisional-radiative model for typical re-entry conditions indicated that the distributions of chemical species exhibit large differences from the results obtained by the global air chemical models (Bultel et al 2006;Annaloro & Bultel 2014).…”

Section: Introductionmentioning

confidence: 99%

Numerical study on the non-equilibrium characteristics of high-speed atmospheric re-entry flow and radiation of aircraft based on fully coupled model

Du,

Sun,

Tan

et al. 2023

J. Fluid Mech.

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The strong coupling interactions of non-equilibrium flow, microscopic particle collisions and radiative transitions within the shock layer of hypersonic atmospheric re-entry vehicles makes accurate prediction of the aerothermodynamics challenging. Therefore, in this study a self-consistent non-equilibrium flow, collisional–radiative reactions and radiative transfer fully coupled model are established to study the non-equilibrium characteristics of the flow field and radiation of vehicle atmospheric re-entry. The comparison of the present calculation results with flight data of FIRE II and previous results in the literature shows a reasonable agreement. The thermal, chemical and excited energy level non-equilibrium phenomena are obtained and analysed for the different FIRE II trajectory points, which form the critical basis for studying the heat transfer and radiation. The non-equilibrium distribution of excited energy levels significantly exists in the post-shock and near-wall regions due to the rapid vibrational dissociation and electronic under-excitation, as well as the wall catalytic reactions. The analysis of stagnation-point heating of FIRE II illustrates that the translational–rotational convection and the dissociation component diffusion play key roles in the aerodynamic heating of the wall region. The spectrally resolved radiative intensity in the entire flow field indicates that the vacuum ultraviolet radiation caused by the high-energy nitrogen atomic spectral lines makes the main contribution to the radiative transfer. Finally, it is found that the non-equilibrium flow–radiation coupling effect can exacerbate the excited energy level non-equilibrium, and further affect the gas radiative properties and radiative transfer. This fully coupled study provides an effective method for reasonable prediction of atmospheric re-entry flow and radiation fields.

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Flow-radiation coupling inCO2hypersonic wakes using reduced-order non-Boltzmann models

Cited by 37 publications

References 51 publications

Advances in non-equilibrium $$\hbox {CO}_2$$ plasma kinetics: a theoretical and experimental review

Advances in non-equilibrium $$\hbox {CO}_2$$ plasma kinetics: a theoretical and experimental review

Consistent Kinetic And Continuum Dissociation Models For High-Temperature Air

Numerical study on the non-equilibrium characteristics of high-speed atmospheric re-entry flow and radiation of aircraft based on fully coupled model

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