A study by emission spectroscopy of the active species in pulsed DC discharges

Brühl, Sonia Patricia; Russell, Marc; Gómez, B J; Grigioni, G.; Feugeas, J.; Ricard, A.

doi:10.1088/0022-3727/30/21/002

Cited by 48 publications

(34 citation statements)

References 12 publications

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“…2 [22]. The sequential intensity of vibrational bands of the second positive system N 2 (C 3 Π u → B 3 Π g ) is related to the population density of the respective state as below [23,29].…”

Section: Spectrum Analysis and Evaluation Of Plasma Parametersmentioning

confidence: 99%

Spectroscopic evaluation of vibrational temperature and electron density in reduced pressure radio frequency nitrogen plasma

Fatima

Ullah

Ahmad³

et al. 2021

SN Appl. Sci.

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The optical emission spectroscopy technique is used to determine the vibrational temperature of the second positive band system,$$ N_{2} (C,\upsilon^{^{\prime}} - B,\upsilon^{^{\prime\prime}}$$ N 2 ( C , υ ′ - B , υ ″ ) in the wavelength range 367.1–380.5 nm by using the line-ratio and Boltzmann plot methods. The electron temperature is evaluated from the intensity ratio of the selected molecular bands corresponding to $$N_{2}^{ + } (B,\upsilon - X, \upsilon^{^{\prime}} , $$ N 2 + ( B , υ - X , υ ′ , 391.44 nm), and, $$N_{2} (C,\upsilon^{^{\prime}} - B,\upsilon^{^{\prime\prime}}$$ N 2 ( C , υ ′ - B , υ ″ , 375.4 nm) transitions, respectively. The selected bands have a different threshold of excitation energies and thus serve as a sensitive indicator of the electron energy distribution function (EEDF). The electron density has been determined from the intensity ratio of the molecular transitions corresponding to $$N_{2}^{ + } (B,\upsilon - X, \upsilon^{^{\prime}} , $$ N 2 + ( B , υ - X , υ ′ , 391.44 nm), and, $$ N_{2} (C,\upsilon^{^{\prime}} - B,\upsilon^{^{\prime\prime}}$$ N 2 ( C , υ ′ - B , υ ″ , 380.5 nm) for different levels of pressure and radio frequency power. The results show that the vibrational temperature decreases with increasing nitrogen fill pressure and radio frequency power. However, the electron temperature increases with radio frequency power and reduces with fill pressure. The electron density increases both with nitrogen fill pressure and radio frequency power that attributes to the effective collisional transfer of energy producing electron impact ionization. Plasma parameters show a significant dependence on discharge conditions and can be fine-tuned for specific surface treatments. Article Highlights Spectrum analysis of RF-driven nitrogen plasma for varying discharge conditions Evaluation of vibrational temperature using line-ratio and Boltzmann plot methods Comparison of vibrational temperatures for line-ratio and Boltzmann plot methods Evaluation of electron temperature and density using the intensity-ratio of bands Correlation of temperature and density with varying fill pressure and RF power

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Section: Spectrum Analysis and Evaluation Of Plasma Parametersmentioning

confidence: 99%

Spectroscopic evaluation of vibrational temperature and electron density in reduced pressure radio frequency nitrogen plasma

Fatima

Ullah

Ahmad³

et al. 2021

SN Appl. Sci.

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“…This results are characteristic for negative glow discharges, as it has been previously reported. 5,12,13 The relative intensities which correspond to the excited species of N 2 z (391 . 4 nm) and Fig.…”

Section: Resultsmentioning

confidence: 99%

“…5 Few results on the influence of current density have been reported, 1,6-8 mainly related to its influence on the hardness of the nitrided samples. Some authors [9][10][11] have determined that both microstructural configuration and uniformity of the nitrided layer are influenced by the sample geometry and its size, as well as its relative position inside the vacuum chamber.…”

Section: Introductionmentioning

confidence: 99%

Ion nitrided AISI H13 tool steel Part I – Microstructural aspects

Cruz

Nachez

Nosei

et al. 2006

Surface Engineering

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In the present paper, five different operating conditions of a plasma nitriding process on annealed AISI H13 were investigated. A systematic variation of processing parameters such as gas mixture, time of processing and current density has been carried out in order to study their effect on microstructure. X-ray diffraction, microhardness testing and scanning electron microscopy techniques coupled with semiquantitative energy dispersive X-ray analysis were used to characterise the nitrided samples. The results revealed that the current density during plasma processing has a considerable influence on both the compound layer formation and depth of the diffusion zone. Also, it has been shown that the geometrical configuration of the workload may affect the uniformity of the diffusion zone, giving rise to the presence of heterogeneous nitrogen distribution zones along it.

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“…To the best of our knowledge, it is still very difficult to accurately numerically simulate the detailed characteristics of plasma active species and their effects on ignition or combustion using the commercial software ANSYS FLUENT. In order to overcome this problem, the effects of plasma active species on the air-C 12 H 23 based ignition process is realized by simply varying the concentrations of the O atom, OH radical and CO [59,60]. Table 1 lists the detailed parameters of one-time ignition for numerical comparisons.…”

Section: • Energy and Active Speciesmentioning

confidence: 99%

Experimental and Numerical Investigations of Plasma Ignition Characteristics in Gas Turbine Combustors

et al. 2019

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Reliable ignition is critical for improving the operating performance of modern combustor and gas turbines. As an alternative to the traditional spark discharge ignition, plasma assisted ignition has attracted more interest and been shown to be more effective in increasing ignition probability, accelerating kernel growth, and decreasing ignition delay time. In this paper, the operating characteristic of a typical self-designed plasma ignition system is investigated. Based on the optical experiment, the plasma jet flow feature during discharge is analyzed. Then, a detailed numerical study is carried out to investigate the effects of different plasma parameters on ignition enhancement of a one can-annular combustor used in gas turbines. The results show that plasma indeed has a good ability to expand the ignition limit and decrease the minimum ignition energy. For the studied plasma ignitor, the initial discharge kernel is not a sphere but a jet flow cone with a length of about 30 mm. Besides, the numerical comparisons indicate that the additions of plasma active species and the increases of initial energy, plasma jet flow length and discharge frequency can benefit the acceleration of kernel growth and flame propagation via thermal, kinetic and transport pathways. The present study may provide a suitable understanding of plasma assisted ignition in gas turbines and a meaningful reference to develop high performance ignition systems.

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A study by emission spectroscopy of the active species in pulsed DC discharges

Cited by 48 publications

References 12 publications

Spectroscopic evaluation of vibrational temperature and electron density in reduced pressure radio frequency nitrogen plasma

Spectroscopic evaluation of vibrational temperature and electron density in reduced pressure radio frequency nitrogen plasma

Ion nitrided AISI H13 tool steel Part I – Microstructural aspects

Experimental and Numerical Investigations of Plasma Ignition Characteristics in Gas Turbine Combustors

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