Electron and vibrational temperatures in hypersonic CO2–N2plasma jets

Lago, Viviana; Barbosa, Emerson; Passarinho, F.; Martín, J. P.

doi:10.1088/0963-0252/16/1/019

Cited by 7 publications

(5 citation statements)

References 19 publications

(16 reference statements)

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“…The axial evolution of the vibrational temperature is similar to that obtained for the electron temperature presented in [23] and carried out with Langmuir probes in a 99% N 2 -1% CH 4 plasma with an arc current of 100 A and a total mass-flow rate of 12 slm, yielding 8.2 MJ kg −1 as the specific enthalpy. This behavior could be explained by a relaxation coupling between the vibrational and electronic modes, giving T v ≈ T e as it has already been observed under other plasma conditions simulating a Mars atmospheric entry [41].…”

Section: Discussionsupporting

confidence: 70%

Optical spectroscopy investigation of N₂–CH₄plasma jets simulating Titan atmospheric entry conditions

Ndiaye¹,

Lago²

2011

Plasma Sources Sci. Technol.

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Planetary probes penetrating at supersonic speed into high atmosphere require the development of composite materials for thermal protection of the surface exposed to a high enthalpy flux. Rarefied arc plasmas can be used to simulate the atmospheric re-entry plasmas. The aim of this paper is to describe the latest results of optical emission measurements of the CH (A-X) system, the CN violet (B-X) bands and the NH (A-X) electronic transitions in a N 2 -CH 4 plasma source (Titan's atmosphere) and in a gas mixture of Ar-CH 4 . In order to deduce the plasma parameters, such as rotational and vibrational temperatures, of these molecular species in the plasma environment, numerical simulation codes have been implemented. In this context, rotational temperatures near 7000 K for CN and 3500 K to 2800 K for the hydrides NH and CH, respectively, are observed. The vibrational temperature of the CH molecule is around 3800 K while those of the CN and NH molecules are 9500 K and 7900 K, respectively.

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Section: Discussionsupporting

confidence: 70%

Optical spectroscopy investigation of N₂–CH₄plasma jets simulating Titan atmospheric entry conditions

Ndiaye¹,

Lago²

2011

Plasma Sources Sci. Technol.

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“…Schöemann et al 1) obtained the axial distribution of chemical components in CO2-N2 plasma flows using mass spectrometry and emission spectroscopy. Lago et al 2) investigated the thermochemical states of CO2-N2 arc plasma flows for various CO2 and N2 concentrations, and clarified the influence of concentrations on the vibrational state of CN. The authors have conducted optical diagnoses of CO2-N2 plasma flows in an arc-heated wind tunnel and deduced temperature distribution along the stagnation streamline around a blunt body.…”

Section: Introductionmentioning

confidence: 99%

Flow Characterization of CO2-N2-Ar Plasma in a Hollow Electrode Arc Heater

Yamada

Nakanishi

Kawazoe

2017

AEROSPACE TECHNOLOGY JAPAN

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The purpose of the present study is to characterize the flow of CO2-N2-Ar plasma in a hollow electrode arc heater using optical diagnostics. Spectroscopic measurements are conducted in the region of the arc-heated part. The rotational and vibrational temperatures are determined from the measured spectra of CN Violet ∆v=0 and C2 Swan ∆v=0 using a spectrum fitting technique. It is found that the rotational and vibrational temperatures are almost same, showing that the plasma in the arc heater is close to thermal equilibrium. The chemical composition of the plasma is calculated using the NASA-CEA program. The result shows that Ar, CO, and O are dominant species in the plasma investigated in this study. Although the mole fractions of CN and C2 are extremely low, they are strong radiators in the CO2-N2-Ar plasma. The numerical spectrum in the wide wavelength range is calculated using the chemical composition deduced by the NASA-CEA program and compared with the measured one. The result shows that the numerical spectrum does not agree with the measured one due to contamination caused by carbon. Spectrum calculations are conducted parametrically by changing the chemical composition to investigate the influence of carbon contamination. The numerical spectrum becomes close to the measured one when the mole fractions of CN and C2 decrease, showing that carbon contamination has a significant influence on the reaction processes of the plasma in the arc heater.

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“…[5][6][7][8][9] At the Icare laboratory, Phedra, one of the three wind tunnels of the experimental platform Fast (Facilities for Aerothermodynamics and Supersonic Technology) is dedicated to simulate non equilibrium high enthalpy flows. [10][11][12] The objective of this paper is to provide a set of VUV spectral emission data carried out in Earth and Mars plasmas for a wide range of specific enthalpy values in order to be used in further comparison with numerical simulations.…”

Section: Introductionmentioning

confidence: 99%

Radiation Measurements in Low Pressure High Enthalpy Flows from VUV to near IR region

Lago¹

2015

20th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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This investigation focuses on optical emission characterization carried out in low pressure arc-jet plasma flows applied for the investigation of radiation relevant to Mars exploration and re-entry into Earth. Experiments were performed in the plasma wind tunnel Phedra of the ICARE laboratory, equipped with an arc-jet producing low pressure and supersonic non-equilibrium plasma flows. Spectral emission from 110 nm to 900 nm, have been measured in 97% CO2-3% N2 and 80% N2-20% O2 plasmas operating with a wide range of plasma conditions in order to evaluate the contribution of VUV radiation with respect to the total one. This investigation contributes to get a set of experimental data, giving access to atmospheric entry plasma models used for predicting heat fluxes. Nomenclature HSpecific enthalpy, MJ/Kg V arc Arc voltage, V I arc Arc current, A C p Calorific capacity of water, J/mol K m c Water flow rate of the cathode cooling circuit , l/ṡ m a Water flow rate of the anode cooling circuit , l/ṡ m gas Gas mass flow rate, g/s ∆T c Water temperature increase of the cathode cooling circuit, K ∆T a Water temperature increase of the anode cooling circuit, K λ Wavelength, nm I em Spectral emission intensity, arbitrary unit R U V U Contribution of the VUV radiation, %

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Electron and vibrational temperatures in hypersonic CO₂–N₂plasma jets

Cited by 7 publications

References 19 publications

Optical spectroscopy investigation of N₂–CH₄plasma jets simulating Titan atmospheric entry conditions

Optical spectroscopy investigation of N₂–CH₄plasma jets simulating Titan atmospheric entry conditions

Flow Characterization of CO<sub>2</sub>-N<sub>2</sub>-Ar Plasma in a Hollow Electrode Arc Heater

Radiation Measurements in Low Pressure High Enthalpy Flows from VUV to near IR region

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Electron and vibrational temperatures in hypersonic CO2–N2plasma jets

Cited by 7 publications

References 19 publications

Optical spectroscopy investigation of N2–CH4plasma jets simulating Titan atmospheric entry conditions

Optical spectroscopy investigation of N2–CH4plasma jets simulating Titan atmospheric entry conditions

Flow Characterization of CO<sub>2</sub>-N<sub>2</sub>-Ar Plasma in a Hollow Electrode Arc Heater

Radiation Measurements in Low Pressure High Enthalpy Flows from VUV to near IR region

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Electron and vibrational temperatures in hypersonic CO₂–N₂plasma jets

Optical spectroscopy investigation of N₂–CH₄plasma jets simulating Titan atmospheric entry conditions

Optical spectroscopy investigation of N₂–CH₄plasma jets simulating Titan atmospheric entry conditions