A new experimental device to measure directional spectral emittance of semitransparent media at high temperatures

Lopes, Rogério; Delmas, A.; Sacadura, J. F.

doi:10.1068/htwu133

Cited by 10 publications

(5 citation statements)

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“…Furthermore, the directional spectral emissivity [1,40,53] is derived by the substitution of Eq. (11) into Eq.…”

Section: F Emissivity Evaluation Methodsmentioning

confidence: 99%

Survey of emissivity measurement by radiometric methods

Honner

2015

Appl. Opt.

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A survey of the state of the art in the field of spectral directional emissivity measurements by using radiometric methods is presented. Individual quantity types such as spectral, band, or total emissivity are defined. Principles of emissivity measurement by various methods (direct and indirect, and calorimetric and radiometric) are discussed. The paper is focused on direct radiometric methods. An overview of experimental setups is provided, including the design of individual parts such as the applied reference sources of radiation, systems of sample clamping and heating, detection systems, methods for the determination of surface temperature, and procedures for emissivity evaluation.

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“…Furthermore, the directional spectral emissivity [1,40,53] is derived by the substitution of Eq. (11) into Eq.…”

Section: F Emissivity Evaluation Methodsmentioning

confidence: 99%

Survey of emissivity measurement by radiometric methods

Honner

2015

Appl. Opt.

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“…In this approximation, neither the radiation from the surroundings nor the background radiation S 0 (λ) is taken into account [11][12][13], so Eqs. 2 and 4 can be simplified:…”

Section: Simple Methods (Simple)mentioning

confidence: 99%

Analysis of the Accuracy of Methods for the Direct Measurement of Emissivity

2008

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Emissivity measurements are of great interest for both theoretical studies and technological applications. Emissivity is a property that specifies how much radiation a real body emits as compared to a blackbody. The emissivity determination of a sample should be an easy task: a simple comparison between the sample and blackbody radiation at the same temperature. Unfortunately, when measuring the emissivity, some practical problems arise due to the differences between the true emitted radiation and the detected quantity. To clarify this point, an analysis of different direct methods for emissivity measurement is presented. Furthermore, a method that includes multiple reflections is developed. The systematic errors associated with each method are computed theoretically as a function of wavelength, sample temperature, and emissivity, and the surrounding enclosure temperature and emissivity. In general, the error is very high for small sample enclosures, but it strongly decreases when the enclosure area increases. Although at short wavelengths all the analyzed methods produce similar errors, noticeable differences appear under other conditions, and methods considering more radiation terms do not always produce lower errors.

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“…Several working groups have already performed direct radiometric measurements, which are described, for example, in Refs. [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Development and Evaluation of an Improved Apparatus for Measuring the Emissivity at High Temperatures

Arduini

Manara

Stark

et al. 2021

Sensors

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An improved apparatus for measuring the spectral directional emissivity in the wavelength range between 1 µm and 20 µm at temperatures up to 2400 K is presented in this paper. As a heating unit an inductor is used to warm up the specimen, as well as the blackbody reference to the specified temperatures. The heating unit is placed in a double-walled vacuum vessel. A defined temperature, as well as a homogenous temperature distribution of the whole surrounding is ensured by a heat transfer fluid flowing through the gap of the double-walled vessel. Additionally, the surrounding is coated with a high-emitting paint and serves as blackbody-like surrounding to ensure defined boundary conditions. For measuring the spectral directional emissivity at different emission angles, a movable mirror is installed in front of the specimen, which can be adjusted by a rotatable arrangement guiding the emitted radiation into the attached FTIR-spectrometer. The setup of the emissivity measurement apparatus (EMMA) and the measurement procedure are introduced, and the derived measurement results are presented. For evaluating the apparatus, measurements were performed on different materials. The determined emissivities agree well with values published in literature within the derived relative uncertainties below 4% for most wavelengths.

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A new experimental device to measure directional spectral emittance of semitransparent media at high temperatures

Cited by 10 publications

References 0 publications

Survey of emissivity measurement by radiometric methods

Survey of emissivity measurement by radiometric methods

Analysis of the Accuracy of Methods for the Direct Measurement of Emissivity

Development and Evaluation of an Improved Apparatus for Measuring the Emissivity at High Temperatures

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