Arc Wind-Tunnel Flow Diagnostics by Cavity-Enhanced Absorption Spectroscopy

Takayanagi, Hideaki; Matsui, Makoto; Komurasaki, Kimiya; Ochimizu, Hideaki; Arakawa, Yoshihiro

doi:10.2514/1.39362

Cited by 7 publications

(5 citation statements)

References 16 publications

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“…Thus far, the Pitot pressure and heat flux of arc-heated flows have been obtained as intrusive diagnostic techniques. The spectroscopic analysis of the molecular band, [8], laserinduced fluorescence (LIF) [9,10], and cavity-enhanced absorption spectroscopy [11], which are non-intrusive techniques, have been used to identify arc-heated flow properties. The emission spectra of the arc column in a constrictor revealed the distributions of translational temperature, flow velocity, and electron number density in the heating section [12,13].…”

Section: Introductionmentioning

confidence: 99%

Flow Enthalpy of Nonequilibrium Plasma in 1 MW Arc-Heated Wind Tunnel

Takahashi¹,

Enoki²,

Koike³

et al. 2021

AIAA Journal

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The flow enthalpy of an arc-heated wind tunnel is an important parameter for reproducing planetary entry and performing heating tests. However, its distribution is insufficiently clarified owing to complicated phenomena, such as arc discharge and supersonic expansion. In this study, we assess the enthalpy of an arc-heated flow in a large-scale facility based on measurements and computational results. The flow enthalpy of high-temperature gases, which comprised thermal, chemical, kinetic, and pressure components, was reconstructed based on the measured rotational temperature, heat flux, and impact pressure, in addition to the computational science approach. The rotational temperature of nitric oxide molecules was obtained using emission spectroscopic measurements of band spectra in the near-ultraviolet range. A numerical model was developed and validated based on measured data. The results indicated that the model efficiently reproduced the arc discharge behavior in the heating section and the thermochemical non-equilibrium in the expansion section. It was discovered that the dominant components of the arc-heated flow in the test section were the chemical and kinetic components. The flow enthalpy exhibited a non-uniform distribution in the radial direction. We conclude that the flow enthalpy of the core is approximately 28 MJ/kg at the nozzle exit.

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Section: Introductionmentioning

confidence: 99%

Flow Enthalpy of Nonequilibrium Plasma in 1 MW Arc-Heated Wind Tunnel

Takahashi¹,

Enoki²,

Koike³

et al. 2021

AIAA Journal

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“…LAS is one of the non-intrusive methods and has been applied to various targets in order to estimate the velocity, the translational temperature and the number density of absorbed species. 11) In our experimental apparatus, translational temperature distribution was not uniform. Then, the nonuniformity was investigated by obtaining the absorption profiles horizontally.…”

Section: Introductionmentioning

confidence: 86%

Translational Temperature Distribution in an Inductively Coupled Plasma Flow for Catalytic Efficiency Measurements

Takayanagi

Bauer²,

Osawa

et al. 2010

AEROSPACE TECHNOLOGY JAPAN

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Aiming for evaluating the translational temperature in an argon-oxygen mixed-gas inductively coupled plasma, laser absorption spectroscopy is applied. In order to consider the radial distribution, an Abel inversion, fitting method, is performed to the measured horizontal distributions. As a result, it is found that the radial translational temperature distribution is almost uniform. In addition, the translational temperature estimated by the absorption profile on the center axis is almost same with the averaged value within the test region obtained after Abel inversion. Axial translational temperature distributions are obtained in the surface temperature range from 300 to 1470K at the total pressure of 11Pa for silicon carbide on the center axis. Finally, using the measured translational temperatures, catalytic efficiencies of atomic oxygen recombination are evaluated with the results measured by actinometry.

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“…Numerous laser spectroscopy techniques have been devised to fulfill the essential requirements of atomic diagnostics [3]. Notably, laser absorption spectroscopy [4][5][6] provides a direct means to determine the absolute number density and possesses inherent self-calibration properties, adequately addressing the requirement to measure the absolute atomic number density in the flow field.…”

Section: Introductionmentioning

confidence: 99%

Generating a Sustained Oxygen-Stable Atomic Concentration in a High-Temperature Gas Effect Investigation

Zhi,

Chang,

Huang

et al. 2023

Micromachines

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Modulated laser absorption spectroscopy is an ideal technique for evaluating flow-field parameters and determining flow-field quality by measuring the atoms dissociated in high-temperature environments. However, to obtain the absolute number density of atoms in the flow field, it is necessary to compare the measured modulated absorption spectroscopy signal with a known atomic concentration and establish a quantitative relationship through concentration calibration. Nevertheless, it remains a challenging task to prepare transient atomic samples with known concentrations that meet the calibration requirements. This study utilized the alternating-current glow discharge technique to dissociate oxygen in the air flow, resulting in the continuous generation of oxygen atoms. The absolute number densities of the generated oxygen atoms were determined by measuring the direct absorption spectra of centered on 777 nm for oxygen atoms. The number densities of the generated atoms were finely tuned by adjusting the discharge parameters. Throughout the 120-min continuous operation of the discharge system, the concentration of excited-state oxygen atoms remained stable within the range of (2.51 ± 0.02) × 108 cm−3, demonstrating the remarkable stability of the transient atomic concentration generated by the glow discharge plasma. This observation suggests that the generated atoms can be utilized as a standardized atomic sample of known concentration for absolute concentration calibration purposes.

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Arc Wind-Tunnel Flow Diagnostics by Cavity-Enhanced Absorption Spectroscopy

Cited by 7 publications

References 16 publications

Flow Enthalpy of Nonequilibrium Plasma in 1 MW Arc-Heated Wind Tunnel

Flow Enthalpy of Nonequilibrium Plasma in 1 MW Arc-Heated Wind Tunnel

Translational Temperature Distribution in an Inductively Coupled Plasma Flow for Catalytic Efficiency Measurements

Generating a Sustained Oxygen-Stable Atomic Concentration in a High-Temperature Gas Effect Investigation

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