Accurate numerical model for characteristic temperature acquisition of miniature fixed-point blackbodies

Authors：Sima, Rui-Heng; Hao, Xiao-Peng^*; Song, Jian; Qi, Hong; Yuan, Zun-Dong

Source：MEASUREMENT, 2021, 168: 108462.

DOI：10.1016/j.measurement.2020.108462

• Blackbody
• Fixed-point
• Characteristic temperature
• Thermal resistance

Miniature fixed-point blackbodies (MFPBs) can realize the on-orbit multipoint temperature calibration through the known characteristic temperature. This ability is important for improving the precision and life span of earth observation systems. For acquisition of characteristic temperature, numerical simulation has lower cost and test condition requirements. However, ordinary numerical models can't meet the accuracy requirements of MFPB. The purpose of this paper is established an accurate numerical model for characteristic temperature acquisition of miniature fixed-point blackbodies. A novel thermal resistance equivalent corrected method (TRECM) is proposed in accordance with the difference between the numerical model and actual experiment. The equivalent correction of the total thermal resistance between two temperature points is achieved by correcting a certain term of thermal resistance in the heat flow transfer path. The TRECM can effectively replace the detailed structure, complex surface radiation and unknown parameters. Characteristic temperatures of blackbody are obtained during Ga, Ga-In, and H2O phase transitions at different heating powers by using proposed model. Meanwhile, an experimental system is established to validate the model. The results showed that the average model error of characteristic temperature between the calculated results and the experimental results decreased from 77.2 m K to 6.2 m K by the TRECM.