Bestimmung des gerichteten spektralen Emissionsgrades von Feststoffen im Wellenlängenbereich von 2,5 µm bis 45 µm bei Temperaturen zwischen 80°C und 350°C

Lohrengel, Joachim; Todtenhaupt, R.; Ragab, Marwa A.A.

doi:10.1007/bf01539529

Cited by 14 publications

(10 citation statements)

References 7 publications

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“…This principle is used for the static emissivity measurement, a technique, which is shortly described in the following, referring to the setup used at the PTB [5,6]. A schematic of the experimental setup is shown in Fig.…”

Section: Conventional Methods To Measure the Spectral Emissivitymentioning

confidence: 99%

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A Study on the Feasibility of Measuring the Emissivity with the Laser-Flash Method

et al. 2010

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The laser-flash method is a fast, widely used and well established technique to measure the thermal diffusivity. Since its introduction in the 1960s, it was proposed to expand this technique to the measurement of heat capacity and emissivity. Currently, the measurement of spectral emissivity at high temperatures is connected with relatively large uncertainties, although the spectral emissivity is an essential parameter for applications, e.g., in the lamp industry and fusion research. In this work, a theoretical study is presented on the possibility of emissivity measurements using the laser-flash method. Two mathematical approaches are discussed which solve the problem, that a measured temperature rise-necessary to calculate the emissivity-itself depends on the emissivity. It is shown that both methods have a negligible arithmetic error, making them applicable to be used in future work.

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Section: Conventional Methods To Measure the Spectral Emissivitymentioning

confidence: 99%

“…Several methods have been proposed and applied to measure the emissivity, mostly based on a static measurement principle [5][6][7][8][9][10][11]. These techniques comprise a reference radiation source with a known emissivity and known temperature, which is usually a blackbody with an emissivity close to unity.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Feasibility of Measuring the Emissivity with the Laser-Flash Method

et al. 2010

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“…We will address this need by extending the temperature range of our conventional spectral emissivity measurements in air [3] down to 0 • C with the RBCF. Several major difficulties have to be addressed for emissivity measurements at low temperatures to achieve sufficient uncertainty.…”

Section: Emissivitymentioning

confidence: 99%

“…Another difficulty is the accurate determination of the surface temperature. In our case, this is done by balancing the heat flux through the sample with the heat loss from the sample surface [3]. 1 Here, the major uncertainty results from the part of the model describing the convective heat loss from the sample surface when using the model with our conventional emissivity facility in air.…”

Section: Emissivitymentioning

confidence: 99%

“…With the vacuum infrared standard radiation thermometer (VIRST) [6], the radiation temperature of the VLTBB has been directly compared to the low-temperature heat-pipe blackbodies of PTB that are the national primary standards of radiation temperature from −50 • C to 962 • C. Details are given in Sect. 3. The third position in the source chamber is occupied either by a source under test or by a specific sample holder for spectral emissivity measurements.…”

Section: General Layoutmentioning

confidence: 99%

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Radiation Thermometry and Emissivity Measurements Under Vacuum at the PTB

et al. 2008

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A new experimental facility was realized at the PTB for reducedbackground radiation thermometry under vacuum. This facility serves three purposes: (i) providing traceable calibration of space-based infrared remote-sensing experiments in terms of radiation temperature from −173 • C to 430 • C and spectral radiance; (ii) meeting the demand of industry to perform radiation thermometric measurements under vacuum conditions; and (iii) performing spectral emissivity measurements in the range from 0 • C to 430 • C without atmospheric interferences. The general concept of the reduced background calibration facility is to connect a source chamber with a detector chamber via a liquid nitrogen-cooled beamline. Translation and alignment units in the source and detector chambers enable the facility to compare and calibrate different sources and detectors under vacuum. In addition to the source chamber, a liquid nitrogen-cooled reference blackbody and an indium fixed-point blackbody radiator are connected to the cooled beamline on the radiation side. The radiation from the various sources is measured with a vacuum infrared standard radiation thermometer (VIRST) and is also imaged on a vacuum Fourier-transform infrared spectrometer (FTIR) to allow for spectrally resolved measurements of blackbodies and emissivity samples. Determination of the directional spectral emissivity will be performed in the temperature range from 0 • C to 430 • C for angles from 0 • to ±70 • with respect to normal incidence in the wavelength range from 1 µm to 1,000 µm.References to commercial products are provided for identification purposes only and constitute neither endorsement nor representation that the item identified is the best available for the stated purpose.

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