Rotational temperature behaviour in supersonic jet expansions of molecular nitrogen

AbstractAn atmospheric pressure plasma jet is generated with a cold arc discharge in ambient air. The current-voltage characteristics and optical emission spectra of plasma discharges are investigated. The molecular nitrogen (N2), hydroxyl radical (OH), and oxygen atom (O) are observed and analyzed. Based on the best fit of the simulated spectra of N2 (C3∏u+ − B3∏g+) band and OH (A2∑+ − X2∏) band transition and the experimentally recorded spectra, the rotational temperature and the vibrational temperature of atmospheric pressure cold arc plasma jet (APCAPJ) are estimated.

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Measurements of Rotational Temperature and Density of Molecular Nitrogen in Spark-Plug Assisted Atmospheric-Pressure Microwave Discharges by Rotational Raman Scattering

Japanese Journal of Applied Physics ◽

10.7567/jjap.50.076101 ◽

2011 ◽

Vol 50 (7R) ◽

pp. 076101 ◽

Cited By ~ 4

Author(s):

Mansour ElSabbagh ◽

Shinichiro Kado ◽

Yuji Ikeda ◽

Koichi Sasaki

Keyword(s):

Raman Scattering ◽

Atmospheric Pressure ◽

Rotational Temperature ◽

Molecular Nitrogen ◽

Spark Plug ◽

Microwave Discharges

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A Comparative Study of Rotational Temperatures in a Microwave Plasma: OH Radical versus N2+

Applied Spectroscopy ◽

10.1366/0003702884428581 ◽

1988 ◽

Vol 42 (1) ◽

pp. 96-100 ◽

Cited By ~ 23

Author(s):

John M. Workman ◽

P. A. Fleitz ◽

Harry B. Fannin ◽

Joseph A. Caruso ◽

C. J. Seliskar

Keyword(s):

Comparative Study ◽

Microwave Plasma ◽

Rotational Temperature ◽

Molecular Nitrogen ◽

Oh Radical ◽

Microwave Induced Plasma ◽

Torch Design ◽

Nitrogen Ion ◽

Increasing Temperature

A rotational temperature comparative study of OH radical vs. N2+ was carried out on a low-power helium microwave-induced plasma. Under the prevailing conditions, N2+ was found to provide twice as many usable lines for temperature measurement than did hydroxyl radical. For the particular torch design used, both species exhibited slightly increasing rotational temperatures at lower flow rates. At fixed conditions, OH consistently indicated higher rotational temperatures than those of the molecular nitrogen ion. Positional studies revealed a slightly increasing temperature near the center of the plasma. This work suggests that N2+ may provide a number of advantages over OH radical as a thermometric probe species in the determination of plasma rotational temperature.

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Experimental and numerical investigation of an axisymmetric supersonic jet

Journal of Fluid Mechanics ◽

10.1017/s0022112000002329 ◽

2001 ◽

Vol 426 ◽

pp. 177-197 ◽

Cited By ~ 43

Author(s):

B. MATÉ ◽

I. A. GRAUR ◽

T. ELIZAROVA ◽

I. CHIROKOV ◽

G. TEJEDA ◽

...

Keyword(s):

Rotational Temperature ◽

Supersonic Jet ◽

High Sensitivity ◽

Mach Disk ◽

Low Velocity ◽

Barrel Shock ◽

Global Agreement ◽

Temperature Maps ◽

Subsonic Region ◽

Subsonic Part

A comprehensive study of a steady axisymmetric supersonic jet of CO2, including experiment, theory, and numerical calculation, is presented. The experimental part, based on high-sensitivity Raman spectroscopy mapping, provides absolute density and rotational temperature maps covering the significant regions of the jet: the zone of silence, barrel shock, Mach disk, and subsonic region beyond the Mach disk. The interpretation is based on the quasi-gasdynamic (QGD) system of equations, and its generalization (QGDR) considering the translational–rotational breakdown of thermal equilibrium. QGD and QGDR systems of equations are solved numerically in terms of a finite-difference algorithm with the steady state attained as the limit of a time-evolving process. Numerical results show a good global agreement with experiment, and provide information on those quantities not measured in the experiment, like velocity field, Mach numbers, and pressures. According to the calculation the subsonic part of the jet, downstream of the Mach disk, encloses a low-velocity recirculation vortex ring.

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Diode laser spectroscopy of the weakly bound complex NeCH4

Canadian Journal of Physics ◽

10.1139/p00-081 ◽

2001 ◽

Vol 79 (2-3) ◽

pp. 423-434 ◽

Cited By ~ 4

Author(s):

M Wangler ◽

D A Roth ◽

G Winnewisser ◽

I Pak ◽

A R McKellar

Keyword(s):

Angular Momentum ◽

Diode Laser ◽

Rotational Temperature ◽

Infrared Absorption Spectrum ◽

Supersonic Jet ◽

Tunable Diode Laser ◽

Wave Number ◽

Weakly Bound ◽

Number Range ◽

Absorption Pattern

The infrared absorption spectrum of the weakly bound rare-gasspherical-top complex NeCH4 was discovered and analyzed for the first time. Measurements were made with tunable diode laser spectrometers using a pulsed supersonic jet and a long-path low-temperature absorption cell. Close to the R(0) transition of the methane ν4 fundamental band at 1311.430 cm1, the NeCH4 spectrum was recorded as a very compact absorption pattern. Within a total wave-number range of about 0.1 cm1, P-, Q-, and R-branches are located. As the first step, the NeCH4 spectrum was recorded and analyzed in a supersonic jet at low rotational temperature of about 5 K. Three branches were identified, of which the P- and R-branches were partially resolved and the Q-branch remained unresolved. Compared with the previously measured spectra of ArCH4 and KrCH4 [Z. Naturforsch. A, 53, 725 (1998).], the absorption pattern in the spectrum of NeCH4 is much denser and considerably more compact. However, by analogy with the spectra of ArCH4 and KrCH4, assignment and analysis were carried out using a Hamiltonian model that incorporates a Coriolis interaction between the total angular momentum of the complex and the angular momentum of the methane monomer. This analysis then allowed us to assign the same spectrum as recorded in a long-path (160 m) cell at a higher temperature of 62 K. The observed rotational constant for NeCH4, B"= 0.129(9) cm1, corresponds to an effective intermolecular separation of 3.8 Å. PACS Nos.: 33.20E, 34.25, 35.20P, 36.40

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Sheath Flow Jet Expansions of Liquids and Supercritical Fluids

Applied Spectroscopy ◽

10.1366/0003702874447130 ◽

1987 ◽

Vol 41 (8) ◽

pp. 1358-1361 ◽

Cited By ~ 15

Author(s):

Bruce D. Anderson ◽

Murray V. Johnston

Keyword(s):

Supercritical Fluid ◽

Supercritical Fluids ◽

Gas Flow ◽

Fluorescence Enhancement ◽

Rotational Temperature ◽

Supersonic Jet ◽

Laser Induced Fluorescence ◽

Sheath Flow ◽

Free Jet ◽

Focusing Properties

A method is described for performing supersonic jet spectroscopy of compounds dissolved in a liquid or supercritical fluid. The fluid is expanded through a capillary restrictor into a concentric sheath gas flow of argon. The resulting mixture undergoes further expansion through a 200-μm tapered nozzle. Laser-induced fluorescence of naphthalene is used to probe the cooling and focusing properties of the nozzle. A rotational temperature of 12 K has been obtained for a variety of fluid carriers. No fluorescence enhancement is observed along the centerline of the expansion relative to the results with a conventional free jet expansion.

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