Numerical and Experimental Analysis of Solar Intrusion for Radiometer in Geostationary Orbit

Abstract

In this study, a finite-difference model of a radiometer was established to perform heat transfer analysis. To start with, the computational methodology was introduced along with suitable assumptions. The temperature distribution was calculated based on the advanced finite-difference method with a control volume approach, which can deal with the radiation boundary conditions efficiently. The Oppenheim method was used to calculate the radiation heat transfer inside the radiometer, and the calculation of radiation view factor of the boundary surface was based on the hemicube method. The heat flux calculation was performed based on the Gebhardt method for nonspecular elements and the ray-tracing method for specular elements. The effect of the midnight solar intrusion on the temperature of the second mirror assembly was investigated. Several full disk frame cases and CEI initialization cases were analyzed to determine if the secondary mirror assembly temperatures exceed the mission allowable temperature. The thermal test of the secondary mirror assembly was used to validate the reliability of the thermal model. The results show that the maximum temperature of the secondary housing exceeds the allowable temperature, which will produce a measurable change in instrument performance.