Mass spectrometry and optical spectroscopy in N2-CO2 and N2-CH4 plasma jets

Schoenemann, A. T.; Lago, Viviana; Dudeck, Michel

doi:10.2514/3.806

Cited by 10 publications

(8 citation statements)

References 8 publications

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“…Such a collision, however, can cause vibrational excitation, because the vibrational excitation requires only energy transfer. 22) The vibrational temperature decreases because of the fast vibrational relaxation process. This is because the vibrational relaxation time in the shock layer becomes shorter than that in the free stream due to the high temperature.…”

Section: Spatial Distribution Of Temperaturesmentioning

confidence: 99%

Temperature Evaluation of CO2-N2-Ar Plasma Flows Using the Area Intensity Method

Yamada

Otsuta

Kawazoe

2015

AEROSPACE TECHNOLOGY JAPAN

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The aim of this research is to investigate the thermal nonequilibrium state of CO2-N2-Ar plasma flows generated in an arc-heated wind tunnel using spectroscopic analysis. An area intensity method that uses molecular band spectra is applied to accurately evaluate the thermal nonequilibrium state of the plasma flows. The radiation from CO2-N2-Ar arc plasma flows around a disk model is observed using spectroscopic measurements. The flow temperatures are evaluated by applying the area intensity method to the CN Violet bands dominantly observed in the measured spectra. In the freestream, the vibrational temperature is higher than the rotational temperature due to the vibrational nonequilibrium process. In the shock layer, a faster vibrational relaxation process can be observed because the vibrational temperature starts to decrease after reaching its maximum value. However, the vibrational temperature is still higher than the rotational temperature. Therefore, the vibrational nonequilibrium state is present in the shock layer. In conclusion, we clarify the thermal nonequilibrium state of CO2-N2-Ar arc plasma flows along the stagnation streamline around the disk model.

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Section: Spatial Distribution Of Temperaturesmentioning

confidence: 99%

Temperature Evaluation of CO2-N2-Ar Plasma Flows Using the Area Intensity Method

Yamada

Otsuta

Kawazoe

2015

AEROSPACE TECHNOLOGY JAPAN

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“…Figure 3 compares a spectrum, simulated as reported previously, 21 with a high-resolution spectrum of the CO ͑0,2͒ band recorded from a plasma at power density1, with a CH 4 concentration of 41%. A good agreement is obtained for a rotational temperature of 1400 K, especially for relative intensities.…”

Section: Resultsmentioning

confidence: 99%

Emission Spectroscopy, Mass Spectrometry, and Kinetics in CH[sub 4]–CO[sub 2] Plasmas Used for Diamond Deposition

Met¹,

Persis²,

Vandenbulcke³

et al. 2006

J. Electrochem. Soc.

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Diamond deposition in microwave CH 4 -CO 2 plasmas depends on various parameters that change the nature and the concentration of the various species in the plasma. In this work emphasis was put on the effect exerted by changes in the power density injected in the plasma. These changes were obtained by varying both the microwave power and the pressure. The ro-vibrational temperature and then the kinetic temperature of the heavy species were determined by emission spectroscopy. Variations induced in the nature and the concentration of both stable species ͑H 2 , CH 4 , CO, CO 2 , . . . ͒ and radicals ͑H, OH, CH 3 , C 3 H 3 , C 3 H 5 , ...͒ were derived from analyses performed with a mass spectrometer associated to a molecular beam sampling technique. Modeling based on various reactor configurations showed that the kinetics in the plasma is principally controlled by the gas temperature at the highest power density, whereas reactions with electrons are needed to initiate the mechanism at low power densities. The comparison of computed and experimental concentration profiles also shows that the influence of the residence time is of capital importance when CH 4 /CO 2 plasmas are used for diamond deposition. This parameter allows explaining the correlation between the experimental conditions and the etching/deposition domains.

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“…1,7,32 This is also an arc-jet experiment. Oxygen and argon are mixed and introduced together into the arc chamber with controlled flow rates ͑7% oxygen in argon͒.…”

Section: The Arc Jet Experiments Of Laboratoire D'aé Rothermiquementioning

confidence: 96%

Simple model for the electronic relaxation during the expansion of a plasma generated in an Ar–O2 mixture

Lebehot¹,

Kurzyna

Lago³

et al. 1999

Physics of Plasmas

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The local properties of a plasma free jet are calculated with a collisional-radiative model where electron density and temperature are included as parameters. The kinetic equations are written for all the electronic states of the atomic species Ar and O. In the first step, only excitation and de-excitation by electron collisions are taken into account, together with spontaneous radiative decay. This allows the problem to be treated as a linear system of equations represented by a matrix. In the second step, collisional processes with atoms and residual molecules are included. The number of adjustable parameters is limited to the normalization factor of the reaction rate constants for excitation by electrons, the degree of dissociation of oxygen at the nozzle exit, and to the relative number of singly charged ions for oxygen and argon along the axis. Electron temperature and density are measured experimentally, or obtained separately from another calculation. Then, the population density of any level can be obtained in any point of the free jet. The results are compared, on the axis, with those of three different experiments, and the agreement is quite satisfactory in any case.

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Mass spectrometry and optical spectroscopy in N2-CO2 and N2-CH4 plasma jets

Cited by 10 publications

References 8 publications

Temperature Evaluation of CO<sub>2</sub>-N<sub>2</sub>-Ar Plasma Flows Using the Area Intensity Method

Temperature Evaluation of CO<sub>2</sub>-N<sub>2</sub>-Ar Plasma Flows Using the Area Intensity Method

Emission Spectroscopy, Mass Spectrometry, and Kinetics in CH[sub 4]–CO[sub 2] Plasmas Used for Diamond Deposition

Simple model for the electronic relaxation during the expansion of a plasma generated in an Ar–O2 mixture

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