Updated measurement method and uncertainty budget for direct emissivity measurements at the University of the Basque Country

Abstract

This work reports on the upgrades made to the direct emissivity measurement facility of the UPV/EHU. The instrumental improvements consist of, among others, a high-vacuum system and wider temperature range (300 − 1273 K). Methodological developments include a refined measurement equation with updated parameters and a reworked ISO-compliant uncertainty budget, and a Monte Carlo procedure for accurate calculations of total emissivities from spectral data. These upgrades have been demonstrated and validated in measurements of both metallic and ceramic materials. The results obtained in this work are applicable to similar experimental devices for emissivity measurements in order to report reliable emissivity data.

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

“…Furthermore, the relative uncertainty increases for shorter wavelengths below 8 µm, as well as for longer wavelengths above 12 µm for low emissivities. The tendentious course of the relative uncertainties is similar to the characteristics of the relative uncertainties of emissivities measurements, which can be found in the literature [ 34 ].…”

Experimental and numerical study of the emissivity of rolled aluminum

“…A 50 mm × 50 mm rolled aluminum sample was purchased from Goodfellow, with a thickness of 3 mm and 99.999% purity. The directional spectral emissivity of the sample was measured using the HAIRL emissometer of the University of the Basque Country, which can perform emissivity measurements up to 1273 K in a controlled atmosphere [19]. The emissometer consists of a Bruker IFS 66v/S vacuum FTIR spectrometer, an Isotech Pegasus R blackbody used as a reference, a sample chamber that allows controlling the atmosphere and an optical entrance that selects between the blackbody and the sample radiation.…”

“…The sample temperature was measured using two Type K thermocouples installed at 5 mm from the measurement spot. Measurements were performed in high vacuum (5 ⋅10 −5 hPa) from 423 K to 823 K. An extensive revision of the uncertainty budget of this instrument as a function of temperature and wavelength for metallic and ceramic materials is available [19]. For pure metals at moderate temperatures, the uncertainty is dominated by the sample temperature at shorter wavelengths and by the sample surroundings and room-temperature blackbody reference at longer ones.…”

IV. Ikergazte. Nazioarteko ikerketa euskaraz. Kongresuko artikulu bilduma. Ingeniaritza eta Arkitektura

“…Arazo honi aurre egiteko, emisibitate altuko estaldurak erabiltzen dira askotan, baina konponketa hori ezin da kasu guztietan erabili. Horregatik, industria metalurgikoaren beharrak erantzuteko diseinatu eta eraiki zen EHUn zehaztasun handiko emisometro infragorri bat (Echániz et al, 2018;González de Arrieta et al, 2020).…”

“…Tresna honek leku pribilegiatua du emisibitateari buruzko literatura zientifikoan, eta bi hamarkada inguruko ibilbidea du. Hala ere, duela gutxi handitu eta hobetu egin da, besteak beste, emisio txikiko materialetan (metal puruetan, adibidez) neurtzeko gaitasuna hobetzeko (González de Arrieta et al, 2020). Emisometroaren irudi eskematikoa 2.a irudian erakusten da.…”