New automated apparatus for the measurement of spectral emissivity of nonconducting materials by high-speed spectrometer

Dozhdikov, V. S.; Petrov, V. S.

doi:10.1068/htrt41

Cited by 8 publications

(5 citation statements)

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“…In [7][8][9], a high-speed spectroscopy method for the measurement of the emissivity at high temperatures was proposed. However, the temperature of investigated matters was defined by optical pyrometers in these methods.…”

Section: Introductionmentioning

confidence: 99%

Determination of the true temperature of emitted radiation bodies from generalized Wien's displacement law

Fisenko¹,

Ivashov

1999

J. Phys. D: Appl. Phys.

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The temperature dependence of the 'generalized' Wien displacement law for tantalum and luminous-flames has been investigated. It is shown that the emitted thermal radiation of tantalum belongs to the same universality class as that of tungsten and zirconium and titanium carbides. The emitted thermal radiation of luminous flames belongs to the universality class as that of a black body. The true temperatures of investigated matter are defined.

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Section: Introductionmentioning

confidence: 99%

Determination of the true temperature of emitted radiation bodies from generalized Wien's displacement law

Fisenko¹,

Ivashov

1999

J. Phys. D: Appl. Phys.

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“…An example of direct method is the so-called furnace drop technique proposed by Dozhdilkov et al [31]. This technique consists in inserting the sample inside a commercial cavity blackbody until the sample temperature stabilizes.…”

Section: Direct Methodsmentioning

confidence: 99%

A fast and versatile method for spectral emissivity measurement at high temperatures

Bakali

Gilblas

Pottier

et al. 2019

Review of Scientific Instruments

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In this paper, the development of a new device for high temperature emissivity measurement is described. This device aims at measuring both spectral and total emissivity for a thermal range of 600 to 1000°C. The device main targeted properties were both versatility and simplicity. To do so, a rigorous selection was made for each component: heating system, heat source, sample holder, measuring devices. Sample dimensions and the corresponding sample holder were optimized through a ray tracing model computation. Selection of sensors to compute a total emissivity was also especially discussed. A NIR spectrometer, and two MIR cameras covering [3-5] and [7.5-13]µm equipped with optical filters were chosen for spectral measurements. The major impediment was the separation between sample signal and various spurious signals emitted by environment. A specific measurement methodology was then made for each bandwidth to resolve this issue. A reference material was chosen for the device validation: Platinum. Spectral emissivity measurements were then compared to values from a commercial spectrometer. A good agreement was found for NIR and the first MIR band measurements and a higher error was seen in MIR second band which is explained by a less favorable signal to noise ratio. Integrated emissivity is then calculated and compared to values found in the literature. A good agreement between those values is found and similar trends with temperature are observed. The device is then validated for spectral and total emissivity measurement. Device versatility and simplicity allows an easy adaptation to a large area of applications.

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“…According to Eqs. (5), (7), and (8) and thanks to Helmholtz's reciprocity theorem applied to bidirectional reflectivity ρ ⃗ r 0 ,⃗ x 0 (λ, T ), the emissivity is then expressed as a function of the measured bidirectional reflectivity in a single direction ⃗…”

Section: B Background Of the Physical Principle Of The Thermoreflectmentioning

confidence: 99%

“…Emissivity can be directly measured according to the definition (ratio of material emissivity to black body emissivity). 7 However, for each measurement, the temperature must be specified to calculate emissivity, so the two parameters are dependent. Alternatively, emissivity can be understood by indirect methods through absorptivity or reflectivity measurements.…”

Section: Introductionmentioning

confidence: 99%

Bi-color near infrared thermoreflectometry: A method for true temperature field measurement

Sentenac

Gilblas

Hernández

et al. 2012

Review of Scientific Instruments

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In a context of radiative temperature field measurement, this paper deals with an innovative method, called bicolor near infrared thermoreflectometry, for the measurement of true temperature fields without prior knowledge of the emissivity field of an opaque material. This method is achieved by a simultaneous measurement, in the near infrared spectral band, of the radiance temperature fields and of the emissivity fields measured indirectly by reflectometry. The theoretical framework of the method is introduced and the principle of the measurements at two wavelengths is detailed. The crucial features of the indirect measurement of emissivity are the measurement of bidirectional reflectivities in a single direction and the introduction of an unknown variable, called the "diffusion factor." Radiance temperature and bidirectional reflectivities are then merged into a bichromatic system based on Kirchhoff's laws. The assumption of the system, based on the invariance of the diffusion factor for two near wavelengths, and the value of the chosen wavelengths, are then discussed in relation to a database of several material properties. A thermoreflectometer prototype was developed, dimensioned, and evaluated. Experiments were carried out to outline its trueness in challenging cases. First, experiments were performed on a metallic sample with a high emissivity value. The bidirectional reflectivity was then measured from low signals. The results on erbium oxide demonstrate the power of the method with materials with high emissivity variations in near infrared spectral band.

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New automated apparatus for the measurement of spectral emissivity of nonconducting materials by high-speed spectrometer

Cited by 8 publications

References 0 publications

Determination of the true temperature of emitted radiation bodies from generalized Wien's displacement law

Determination of the true temperature of emitted radiation bodies from generalized Wien's displacement law

A fast and versatile method for spectral emissivity measurement at high temperatures

Bi-color near infrared thermoreflectometry: A method for true temperature field measurement

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