Authors: Wenjie Zhu Deheng Shi Zunlue Zhu Jinfeng Sun
Publish Date: 2016/06/16
Volume: 70, Issue: 4, Pages: 1083-1090
Abstract
This work investigated the normal spectral emissivity characteristics of Steel 304 over a temperature range from 800 to 1100 K and a wavelength range from 14 to 21 μm In the experiments specimens were heated in air for 6 h at a certain temperature Two platinum–rhodium thermocouples were symmetrically welded onto the front surface of the specimens near the measuring area for accurate monitoring of the surface temperature The temperatures measured by the two thermocouples had an uncertainty of 1 K The average of their readings was regarded as the temperature of the specimen surface The radiance stemming from the specimens were measured at temperatures from 800 to 1100 K in increments of 20 K by multispectral radiation thermometry Variation in the normal spectral emissivity with respect to wavelength and temperature was studied for different heating times The effect of surface oxidization on the accurate prediction of the specimen surface temperature was discussed Similar variation in the normal spectral emissivity for different heating times showed that the emissivity followed a certain rule Nine emissivity models were examined for accuracy in the temperature prediction The results showed that the fourparameter loglinear wavelength and line wavelength emissivity models generated best overall temperature prediction We concluded that the effect of surface oxidization on the emissivity models of Steel 304 could be dismissed and that the same models could be used to predict its surface temperature from 800 to 1100 KThis work is sponsored by the National Natural Science Foundation of China under Grant Nos 61077073 and 61177092 the Program for Science and Technology Innovation Talents in Universities of Henan Province in China under Grant No 2008HASTIT008 and the Key Program for Science and Technology Foundation of Henan Province in China under Grant No 102102210072
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