| 摘要: | 隨著衛星航太技術、移動通訊和電子元件技術的快速發展，低軌衛星通訊的應用時機已然成熟。然而，在低軌衛星在軌道上運作時，工作溫度相差甚大，在面陽側溫度高達80 oC，而在背陽側溫度則會低至-40 oC。鋁氨溝槽熱管常用於衛星的熱管理，但接近該工作溫度範圍的研究不多。因此本研究透過實驗量測了鋁氨熱管工作溫度-40到80 oC之性能，並比較不同冷卻與加熱方式的性能變化，以及熱管在蒸發段高於冷凝段時，傾斜角10 °到水平之間的性能變化。結果顯示雙面加熱雙面冷卻有最好的性能表現。而在傾斜測試中，隨著角度增加，熱管最大熱傳量與最低熱阻也隨之變差，因為溝槽能提供的毛細力少，對重力的抗拒小，液體無法抵抗重力流動到蒸發段，造成燒乾提早熱阻增加。
銅水熱管目前在地面應用已是相當成熟的技術，若能應用於低軌衛星中，具有低成本、高彎曲性與傳輸高熱通量的優勢，可用於衛星內部發熱元件到機殼之間的熱傳輸，但在太空低溫應用中，低於冰點的溫度可能會導致熱管內部流體結凍、膨脹破壞蕊材，造成性能變差。目本實驗透過實驗調查銅水燒結熱管，在蕊材層厚（0.9、0.5 mm）、三種填充率（60、70、80%），冷凝段-40 oC時觀察冷凝段結凍時的最大熱傳量與最低熱阻，並透過控制冷凝段-40 oC與80 oC的循環測試觀察熱管是否在反覆的凍融下性能是否下降。結果顯示燒結厚度0.9mm、填充率80%有較低的熱阻，因為較厚的蕊材與較多的填充，有較多的液體處於流動狀態，使熱管能啟動工作。此外，熱管在172次凍融循環後並沒有發現性能下降。
;With the rapid development of satellite aerospace technology, mobile communications, and electronic components, the application of low-earth orbit (LEO) satellite communications has become feasible. However, during the operation of LEO satellites, the working temperatures vary significantly, ranging from 80°C on the sun-facing side to -40°C on the shadow side. Aluminum-ammonia grooved heat pipes are commonly used for satellite thermal management, but there is limited research near this temperature range. Therefore, this study experimentally measured the performance of aluminum-ammonia heat pipes within a working temperature range of -40°C to 80°C. It compared the performance variations under different cooling and heating methods, and examined the performance changes with tilt angles from 10° to horizontal when the evaporating section was higher then condensing section. The results showed that 2-side heating with 2-side cooling had the best performance. In the tilt test, as the angle increased, the maximum heat transfer rate and minimum thermal resistance of the heat pipe worsened. This is because the capillary force provided by the grooves is insufficient to counteract gravity, causing the liquid to fail to return to the evaporator section, leading to early dry-out and increased thermal resistance.
Currently, copper-water heat pipes are a well-established technology for ground applications. If applied to LEO satellites, they offer low cost, high flexibility, and high heat flux transfer capabilities. It can be used for heat transfer from internal heating elements to the component box. However, in low-temperature space applications, temperatures below 0 oC can cause water to freeze and expand, potentially damaging the wick structure and degrading performance. This study experimentally investigated the performance of copper-water sintered heat pipes with wick thicknesses of 0.9 mm and 0.5 mm, and three filling rate (60%, 70%, 80%). It observed the maximum heat transfer rate and minimum thermal resistance when the condensing section was at -40°C, and tested whether performance declined after repeated freeze-thaw cycles between -40°C and 80°C. The results showed that a wick thickness of 0.9 mm and a filling rate of 80% had the lowest thermal resistance. The thicker wick and higher filling rate provided more liquid in a flowing state, and enabling the heat pipe to operate. Furthermore, no performance degradation is observed after 172 freezing-thawing cycles. |
