Abstract：The integrated blackbody method is an important approach for obtaining the high-temperature spectral emissivity of materials. When using this method to measure the sample state, the radiation enhancement effect caused by reflection in the cavity of the convection suppression device at the cavity mouth is known as the cavity effect. The existence of this effect results in significant systematic bias in the emissivity measurement results using the integrated blackbody method. Currently, there is a lack of research on the mechanism of this effect, correction methods, and experimental studies on typical samples. Therefore, investigates the mechanism of cavity reflection and spontaneous radiation effects, and proposes a theoretical model for the correction factor of the non-isothermal boundary cavity effect in the integrated blackbody method. Based on the finite element method, theoretical calculations of the correction factor for the non-isothermal boundary cavity effect are carried out for samples with different emissivities and specific temperature fields. The results are compared with the correction factors obtained based on the Monte Carlo ray tracing method, showing good consistency with a maximum deviation of no more than 2.5%. Experimental studies are conducted on a platinum material sample in the temperature range of 1000°C and wavelength range of (12-14) μm. The emissivity measurement results using the integrated blackbody method, after correction for the non-isothermal boundary cavity effect, are compared with the results obtained using the discrete blackbody method, showing an improvement in consistency from 0.08 to 0.03.
2024, Vol. 45 
