| 摘要: | 隨著全球對高速與可靠的通訊需求快速成長，衛星的發射數量隨之增加，具距離地表500至2000公里的衛星稱為低軌衛星，低軌衛星工作包含通訊、遙測、導航、氣象以及科學探索和國防，在面相太陽時80 oC，而在背對太陽時溫度降至-40 oC。銅水熱管常用在衛星的熱管理，在-40 oC環境時銅水熱管裡面的水會隨之結凍，進而影響衛星內部的散熱使內部計算元件溫度上升導致運算速度降低。鋁氨熱管近年來常用於衛星在外太空的散熱元件，氨在-40 oC時是液態，所以此研究以設計鋁氨熱管於應用，從初步設計熱管內部結構，並測試不同氨填充率的熱傳性能。
在冷凝溫度25 oC時，氨的填充率從46.4 %到8.2 %，在高填充率時，熱阻較大且鋁氨熱管的溫度分布相近，在填充率14.9 %且加熱量380 W時，熱傳性能最好，得到最低熱阻為0.052 (oC/W)。當填充率低於填充率14.9 %，鋁氨熱管蒸發段尾部溫度上升，熱阻開始增加，最大熱傳量減少。
;With the global demand for high-speed and reliable communication rapidly increasing, the number of satellite launches has also risen significantly. Satellites operating at altitudes of approximately 500 to 2000 km above the Earth’s surface are classified as low Earth orbit (LEO) satellites. These satellites perform various functions, including communication, remote sensing, navigation, meteorology, scientific exploration, and national defense. During operation, when facing the sun, the satellite surface temperature can reach 80 °C, while on the shaded side it can drop to −40 °C.Copper–water heat pipes are commonly used in satellite thermal management systems; however, in environments as cold as −40 °C, the water inside may freeze, which degrades thermal performance and causes the internal components to overheat, reducing computational efficiency. In recent years, aluminum–ammonia heat pipes have been increasingly adopted for space applications, as ammonia remains in a liquid state at −40 °C, making it suitable for extreme low-temperature operation.At a condenser temperature of 25 °C, the ammonia filling ratio was varied from 46.4 % to 8.2 %. At higher filling ratios, the thermal resistance was larger, and the temperature distribution along the aluminum–ammonia heat pipe was relatively uniform. When the filling ratio was 14.9% and the heat input was 380 W, the heat pipe exhibited the best thermal performance, achieving the lowest thermal resistance of 0.052 (°C/W). When the filling ratio was lower than 14.9 %, the temperature at the end of the evaporator section increased, the thermal resistance began to rise, and the maximum heat transfer rate decreased. |
