ISSN Online: 2379-1748
7th Thermal and Fluids Engineering Conference (TFEC)
SJR:
0.152
SNIP:
0.14
CiteScore™::
0.5
Indexed in
SPECTROSCOPIC AND PYROMETRIC TEMPERATURE MEASUREMENTS OF HEATED TYPE B AND S THERMOCOUPLES
Resumo
This research experimented with two different non-contact methods for determining the surface temperature of a hot object (in this case heated type-B and type-S thermocouples): multiwavelength spectrometry and three-wavelength pyrometry. A spectrometer was first used to obtain the spectral emissivities and temperatures of the object at a large number of wavelengths
(in the range of 600-1000 nm). A three-wavelength pyrometer was then used to measure the radiation intensity of the object at three distinct wavelength bands (centered at 640, 810 and 998
nm); temperatures were determined either with the gray-body assumption (i.e., constant emissivities in wavelength pairs) or with the spectral emissivities obtained with the spectrometer.
If the spectrometry-derived emissivities of the object at the aforementioned wavelengths of the pyrometer were used in the pyrometric calculations, then the temperatures of the two instruments should agree. To test this hypothesis, the temperature of the B-type and S-type thermocouples were also acquired from their generated voltages, and they were contrasted with those obtained with both the spectrometric and pyrometric measurements. The spectral emissivity values of the
S-type thermocouple were compared with relevant values published in the literature. The emissivity and temperatures for a B-type thermocouple are new additions to the literature.