低溫熱管設計及性能研究

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题名:	低溫熱管設計及性能研究
作者:	吳昊軒;Wu, Hao-Hsuan
贡献者:	能源工程研究所
关键词:	熱管;冷媒;熱阻;通訊衛星;冷鏈運輸;Heat pipes;Refrigerants;Thermal Resistance;Communication satellites;Cold chain transportation
日期:	2023-08-09
上传时间:	2024-09-19 16:03:46 (UTC+8)
出版者:	國立中央大學
摘要:	近年來，隨著通信衛星和冷鏈運輸應用的逐漸普及，低溫熱管的重要性日益凸顯。大多數這些應用的溫度範圍為 -20 ~ -40 oC。然而，在此溫度範圍內進行的研究卻很少。這項研究提供了在接近 -40 oC 的溫度下運行的熱管傳熱性能的實驗測量。採用外徑8mm、10mm、12mm三種不同的燒結銅熱管，工作流體使用冷媒R-32、R-134a以及R-245fa進行測試。根據實驗結果，冷媒R-32的熱傳性能最佳，其次是冷媒R-134a，而冷媒R-245fa表現最差。可能的原因是，與冷媒R-134a和冷媒R-245fa相比，冷媒R-32具有最好的性質，如飽和蒸汽壓差、液體熱傳導係數和液體傳輸係數。在冷媒R-245fa及R-134a熱管，管徑12mm熱管的整體熱阻低於管徑10mm熱管，是因為在較大的管徑中，蒸發段和冷凝段的液汽介面熱傳面積上升，液汽介面蒸發冷凝熱阻下降，整體熱管熱阻下降。而在冷媒R-32熱管，因為管徑12mm熱管的蕊材厚度厚於管徑10mm熱管，造成熱管的流體-蕊材結合熱阻上升，熱管蕊材厚度對熱阻的影響較多，使得在不同管徑中冷媒R-32熱管的熱阻表現上，管徑10mm熱管熱阻是低於管徑12mm熱管。 ;Due to the gradually popularized of the communication satellite and cold chain transportation applications, low-temperature heat pipes are increasing it importance drastically in the past years. Most of those applications are in the temperature range of -20 to -40 oC. However, very few researches have been conducted within this temperature range. This study provided an experimental measurement of heat transfer performance of heat pipes operating at temperatures near -40 oC. Using three different sintered copper heat pipes with outside diameters of 8mm, 10mm, and 12 mm and using refrigerant R-32, R-134a, and R-245fa as working fluid were tested. Based on the experimental results, the thermal resistance of refrigerant R-32 is best, followed by refrigerant R-134a, while refrigerant R-245fa performs the worst. The possible reason is that refrigerant R-32 has best property of saturated vapor pressure gradient, liquid thermal conductivity, and liquid transport parameter compared to refrigerant R-134a and refrigerant R-245fa. The overall thermal resistance of the diameter of 12mm heat pipe is lower than that of the diameter of 10mm heat pipe in both refrigerant R-245fa and R-134a heat pipes. The reason is the larger diameter heat pipe, the heat transfer area of the liquid-vapor interface in the evaporating and condensing sections increases, leading to a decrease in the liquid-vapor interface thermal resistance and thus reducing the overall thermal resistance of the heat pipe. However, in the R-32 refrigerant heat pipe, the diameter of 12mm heat pipe has a thicker wick than the diameter of 10mm heat pipe. This results in an increase in the thermal resistance with the fluid-wick interface. The thickness of the wick has a more significant impact on the thermal resistance, causing the diameter of 10mm heat pipe has lower thermal resistance than the diameter of 12mm heat pipe in refrigerant R-32 heat pipes.
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