The effect of melting point and combination of phase change materials on the thermal control performance of small satellites in the thermal environment of low earth orbit: Numerical study

Thermal management of small satellites in the thermal environment of low earth orbit is a crucial task. Any satellite in low earth orbit is subjected to two distinct thermal conditions for the duration of its orbit: extreme hotness and extreme coldness. Phase change materials (PCM) are promising candidates for the thermal control of small satellites in low earth orbit thermal conditions. The present work provides a numerical analysis of a thermal storage panel (TSP) using PCM. The TSP is used to improve small satellites' thermal control performance in the thermal environment of a low earth orbit. An aluminium TSP is designed based on a typical space-approved small satellite battery. It is integrated with five internal fins as a thermal conductivity enhancer. The fins divide the heat sink into six cuboid cavities and are filled with PCM. Three-PCM materials with melting points of 15 degrees C, 21 degrees C, and 26 degrees C are used. The proposed low earth orbit is at an altitude of 500 km and a beta angle of 00; this resulted in an eclipse fraction of 0.37. The TSP is investigated under three levels of heating loads: 10W and 13 W. The TSP is investigated using both single and combinations of PCM. Four combination cases are investigated: (RT 15 & RT 21), (RT 21 & RT 26), (RT 15 & RT 26), and (RT 15 & RT 21 & RT 26). The results report a significant enhancement in the thermal control performance of the PCM-based TSP. At 10W and steady -state conditions, RT 15 records maximum extrema of 21.4 degrees C with a decreasing percentage of 34.6 % compared to the case without PCM. In addition, RT 15 records minimum extrema of 7.8 degrees C with an increase of 162.4 %. TSP with PCM combinations achieve a nearly constant PTD under varying heating loads and hence a constant temperature response amplitude. In addition, the PCM combinations achieve a nearly fixed specific heat with the change in heating load.