Radiation excited by shock waves in a CO2-N2-Ar mixture: Experiment and theory

Zalogin, G. N.; Козлов, П.В.; Kuznetsova, L. A.; Лосев, С. А.; Makarov, V. N.; Romanenko, Yu. V.; Суржиков, С. Т.

doi:10.1134/1.1379629

Cited by 34 publications

(11 citation statements)

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“…According to Gök&en, further validation studies are needed to reduce uncertainties and increase the confidence level of predictions [9]. This could be a significant source of error, as the temperature behind the shock during Titan entry is approximately 13,000 K and, in some cases, for the experimental conditions presented by Brandis et al [8], above 30,000 K. For determining the excitation reaction rates, Zalogin et al [37] conducted a series of shock tube tests in CO 2 -N 2 -Ar gas mixtures at velocities between 3 and 4 km=s and pressures from 66 to 660 Pa. These experiments were used to estimate the collisional excitation and deexcitation rates of CN based on a simplified master equation for CN excited states.…”

Section: B Sensitivity and Important Reactions Analysismentioning

confidence: 96%

Analysis of Nonequilibrium CN Radiation Encountered During Titan Atmospheric Entry

Brandis

Morgan

McIntyre

2011

Journal of Thermophysics and Heat Transfer

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The focus of this paper is to analyze the Titan reaction scheme and determine the mechanisms that control the formation and decay of the radiation emitted by the cyanogen molecule (CN) during entry into Titan's atmosphere. Through a parametric study of important reactions combined with an investigation into reaction pathways, it has been concluded that the coupling between the dissociation of N 2 and the formation of the CN (through the reaction N 2 C $ CN N) controls the radiation decay rate. The reason for the super equilibrium concentrations (approximately 50% higher than equilibrium) was identified to be a result of the N 2 C $ CN N reaction continuing to overproduce the CN after nominal equilibrium values were reached. This is due to the slow buildup of N to drive the reverse reaction. The absolute level of emitted radiation has been shown to be controlled by the lifetime of the CNB state and the excitation of CNX to CNB by heavy particle impact. Thus, it is the conclusion of this paper that CN radiation is primarily controlled by N 2 dissociation.

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Section: B Sensitivity and Important Reactions Analysismentioning

confidence: 96%

Analysis of Nonequilibrium CN Radiation Encountered During Titan Atmospheric Entry

Brandis

Morgan

McIntyre

2011

Journal of Thermophysics and Heat Transfer

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“…It is worth noticing that the recommendations on the excitation constants are given in a number of papers 13,25,27,31,32 . The comparison of recommended excitation constants and the excitation constant used in this part of the work for the CN(B 2 Σ + ) state is shown in Fig.…”

Section: A Rebuil Ding Of Experimental Data Obtained I N Ref 14mentioning

confidence: 99%

“…Due to the reasons mentioned above experimental works concerning the nonequilibriu m kinetics 18 and radiation [13][14][15][16][17] in different gas mixtures appeared. The measurement of various characteristics of nonequilib riu m radiation [13][14][15][16][17] in absolute values is a very challenging (mainly because of calibrat ion of optical part of setup) and very important (it is possible to directly co mpare numerical and experimental results) p roblem.…”

Section: Introductionmentioning

confidence: 99%

“…The measurement of various characteristics of nonequilib riu m radiation [13][14][15][16][17] in absolute values is a very challenging (mainly because of calibrat ion of optical part of setup) and very important (it is possible to directly co mpare numerical and experimental results) p roblem. The experimental investigation of relaxation of vibrational temperature behind the shock front in pure oxygen 18 is also very interesting work since one of its results is that existing models of nonequilib riu m d issociation are not able to reproduce the experimental data when dissociation become nonequilibriu m (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Nonequilibrium Radiation behind the Strong Shock Waves in Marsian and Titan Atmospheres: Numerical Rebuilding of Experimental Data

Dikalyuk

Суржиков

Shatalov

et al. 2012

50th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition

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The computati onal model of nonequili brium radi ation emitted in the relaxati on zone behind shock front is presented in the paper. The hydrodynamic description of relaxati on zone is performed in the framework of Euler equations. The model includes different physical chemical processes such as chemical kinetics, relaxati on of vi brational energy. Also the equation for the determinati on of electron gas temperature is solved. The "justoverl appi ng" line model is used for the calculation of the s pectral emissivity. The presented model is used in order to obtain vari ous characteristics of radiation (spectral emissivity, spatial distri buti on of s pectral emissivity integrated over s pecific wavelength region, maxi mum val ue of the nonequili brium radi ation) behind shock front for the conditi ons which are relevant to the experi mental data obtained on different facilities. Comparison of experi mental and theoretical data is presented in the paper. The reasons for the discrepancies are discussed. Nomenclature x = distance behind the shock front p = pressure ρ = density u = velocity T = translational temperature of the heavy particles x i = mo lar fract ion of i-th chemical co mponent m i = mass of i-th chemical co mponent T V,i,j = vibrational temperature of j-th mode of i-th molecu le θ i,j = characteristic vibrational temperature of j-th mode of i-th mo lecule g i,j = degeneracy of j-th mode of i-th molecu le N s = total number of chemical co mponents N M = number of diato mic and triato mic molecu les among chemical co mponentslar concentrations of i-th chemical co mponent k f i , k r i = forward and reverse rate constant of i-th chemical react ion N r = total number of chemical react ions a ij , b ij = stoichiometric coefficients of the j-th forward and reverse reactions for the i-th chemical co mponent K eq i = equilibriu m constant of i-th reaction e m , e 0 m = number of v ibrational quanta of the m-th vib rational mode and equilibriu m (with translational 2 temperature) nu mber of vibrat ional quanta of the m-th vibrat ional mode Q m VT = term accounting for the translational-vibrational energy exchange of the m-th vibrat ional mode Q m CV = term accounting for the loss and gain of vibrational quanta due to chemical reactions in which the mth vibrational mode participate N VT,m = total number of VT reactions τ m = relaxation time of the m-th vibrational mode τ m,i = relaxation time of the m-th vibrational mode in the i-th VT react ion n e = volume concentration of electrons T e = temperature of electron gas Q ei = term accounting for the contribution of electron-ion collisions to the change of the energy of electron gas Q ea = term accounting for the contribution of electron-atom collisions to the change of the energy of electron gas Q ai = term accounting for the contribution of associative ionization and dissociative recomb ination reactions to the change of the energy of electron gas Q ion = term accounting for the contribution of ionization reactions to the change of the energy of electron gas Q ...

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“…In [39] the error in the measured spectral intensity of radiation was estimated to be 90%. Taking into account this value agreement between experimental and numerical data should be regarded as acceptable.…”

Section: Multi-temperature Kinetics and Just-overlapping Line Modelmentioning

confidence: 99%

Advanced Models in Shock Waves

Colonna¹,

Ammando²,

Dikalyuk³

et al. 2014

TOPPJ

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Abstract:The paper presents three collisional-radiative models developed to investigate non-equilibrium chemistry and radiation in hypersonic shock tubes operating with different planetary atmospheres. An hybrid collisional-radiative model, employing the state-to-state kinetics of electronically excited states of molecules and the multi-temperature approximation for the vibrational degree of freedom is presented first, and applied to the numerical rebuilding of experimental shock tube emission spectra. Next, an hybrid collisional-radiative model for ionized air is presented. This model consider the state-tostate approach for electronic states of atoms and the multi-temperature model for the vibrational populations of diatomic molecules in their ground electronic state. A radiative transport equation is also solved to determine radiative source terms in the kinetic scheme and the enthalpy production due to radiation. The third model considers the state-to-state collisionalradiative model of Jupiter's atmosphere, self-consistently coupled with the Boltzmann equation for free electrons and the radiative transfer equation for the radiation transport in one-dimensional slab geometry.

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Radiation excited by shock waves in a CO2-N2-Ar mixture: Experiment and theory

Cited by 34 publications

References 11 publications

Analysis of Nonequilibrium CN Radiation Encountered During Titan Atmospheric Entry

Analysis of Nonequilibrium CN Radiation Encountered During Titan Atmospheric Entry

Nonequilibrium Radiation behind the Strong Shock Waves in Marsian and Titan Atmospheres: Numerical Rebuilding of Experimental Data

Advanced Models in Shock Waves

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