The Assessment of Multispectral Radiation Thermometry Using Linear and Log-Linear Emissivity Models for Steel

Abstract

Experiments were performed to measure the spectral intensity values of a variety of steel samples at 700, 800, and 900 K. The experimental work is coupled with two commonly used emissivity models, linear emissivity models (LEMs) and log-linear emissivity models (LLEs), to examine multispectral radiation thermometry (MRT) on inferring surface temperature. Overall, the first-order LEM and the first-order LLE show the best compensation for different alloys, number of wavelengths, temperatures, and heating time. The results reveal that the better the emissivity model suitably represents real surface emissivity behavior, the more accurate is the inferred temperature by MRT.

The authors are grateful for the support of the National Science Council of Taiwan (under project number NSC-94-2218-E-006-046). The authors would also like to thank the Gloria Material Technology Corporation (GMTC) in Taiwan for the supply of steel samples and Dr. Jongmook Lim of Spectraline Inc. for technical assistance and instrument support.

Notes

^a n is the minimum number of wavelength required in the MRT model.

Missing values correspond to errors beyond 10%.

^a Wave. No. represents the number of wavelengths: n is the minimum number of wavelengths required in the MRT model and N is the total number of wavelengths available in the examined wavelength range.