空腔效应对集成黑体高温发射率测量影响规律研究OA北大核心CSTPCD

Theoretical models for correction factors of non-isothermal boundary cavity effects in integrated blackbody method are proposed.Based on the finite element method,theoretical calculations of correction factors for non-isothermal boundary cavity effects are carried out under different emissivity samples and specific temperature fields.These calculations are compared with correction factors obtained based on the Monte Carlo ray tracing method,showing good agreement with a maximum deviation of no more than 2.5％.The results indicate that with longer wavelengths and lower sample emissivity,the cavity effect has a greater impact on emissivity measurement results.Emissivity measurements of platinum material samples are conducted at 1 000 ℃ temperature and within the wavelength range of 12～14 µm.These measurements are compared with results obtained using the discrete blackbody method.After correction,the consistency between the integrated blackbody method and the discrete blackbody method is improved from 0.08 to 0.03.This result verifies the feasibility of introducing correction factors for non-isothermal boundary cavity effects in the theoretical model and improves the accuracy of emissivity measurement using this method.