Modelling of radiative heat transfer of a square trihedral design radiator panel on the lunar surface

In this study, a radiative thermal model is developed which can be used to predict the heat transfer performance of radiator panels on the lunar surface. It includes the effects of all environmental sources of radiation experienced on the lunar surface, namely direct and indirect solar radiation, lunar albedo, and infra-red thermal heating from the lunar surface. Ray tracing is used to capture the direct solar irradiation and also to determine surface-to-surface view factors. The radiation network methodology is employed to determine the contribution from diffuse reflections. This model is applied to a retro-reflector-like trihedral design radiator panel. A trihedral is defined as a shape with three sides which meet at a common point. This form aims to minimise the negative effects of environmental radiation while maximising the heat transfer to deep space. For the geometry and conditions studied here, the radiator panel shows good potential as an effective lunar radiator when compared to a flat plate. A change in radiative dissipative performance is observed across the lunar day when the apex angle is varied, with smaller apex angles showing greater rates of heat transfer in the morning compared to larger angles which work best at noon. The orientation of the radiator on the lunar surface was also investigated. It was found that heat transfer rate was largely unaffected by the azimuth angle, however varying the inclination angle from horizontal to vertical causes a significant reduction due to increa sed view factors to the lunar surface. Further work is required to fully characterise this design, including increasing the number of trihedral elements and the inclusion of thermal conduction in the model.