Comparative Study on Radiation Properties of Blackbody Cavity Model Based on Monte Carlo Method

Abstract

In order to improve the absorption of stray radiation traps and thermal radiation detectors of blackbody radiators and enhance the thermal radiation transmission, large aperture and high-emissivity blackbody radiators or compact space-borne blackbody sources can be developed. The design of blackbody cavity with V-grooves is a method to change the effective emissivity of blackbody radiation source. At the design stage, the most important work is to evaluate its radiation characteristics in order to verify the effectiveness of this method. Two kinds of blackbody cavity models are designed in this paper. One is a cylindrical–conical blackbody cavity with a 2-mm deep 50° angle V-grooves (the cavity is 300 mm long and 80 mm in diameter, with a depth of 277 mm the cone part of the cavity is 23.09 mm long, the top angle of the cone is 120°, the wall thickness is 2 mm, and the surface will be painted with 0.95 emissivity coating). The other is the blackbody cavity model with the same structure and smooth inner wall. Using the special software based on Monte Carlo method, the radiation characteristics of the two blackbody cavity models are simulated under isothermal conditions. The average normal effective emissivity and right-conical effective emissivity of the blackbody cavity with different observation radius are obtained, respectively. The results show that the average normal effective emissivity and right-conical effective emissivity of the blackbody cavity with V-grooves on the inner wall are increased. In addition, the experimental results of radiative properties of the blackbody radiator having the V-grooved cavity measured by thermal cavity reflectometry method agree with the theoretical simulation results. Therefore, it is proved that the blackbody cavity with V-grooves on the inner wall (except for special angles) can be an effective way to improve the emissivity of the blackbody source.