Abstract The coupling effect of non-condensable gas (NCG) and evaporator tilts on the steady state operation of a loop heat pipe (LHP) was investigated both experimentally and theoretically in this work. Nitrogen was injected quantitatively into an ammonia-stainless steel LHP to simulate NCG, and the steady state characteristics of the LHP were studied under three typical evaporator tilts. According to the experimental results, the main conclusions below can be drawn. (1) The temperature is the highest under adverse tilt and the lowest under favorable tilt no matter whether there is NCG in LHP. (2) The existence of NCG could cause the increase of temperature under all three typical evaporator tilts, but the temperature increment caused by NCG seems to be relatively small under adverse tilt. (3) The increments of the temperature caused by NCG display different patterns under different tilts. Theoretical analysis was conducted to explain the results: the temperature under the coupling effect of NCG and evaporator tilt was determined by the energy balance between the heat leak from evaporator to compensation chamber and the cooling capacity of returning subcooled liquid. With the increase of heat load, the augmentation of heat leak caused by NCG and the enhancement of subcooled liquid cooling effect were incongruent. The coupling effect of NCG and evaporator tilts should be considered in the terrestrial application of LHP.

中文翻译：

---

蒸发器倾斜对不凝气体回路热管的影响

摘要 在这项工作中，从实验和理论上研究了不可凝气体 (NCG) 和蒸发器倾斜对回路热管 (LHP) 稳态运行的耦合效应。将氮气定量注入氨-不锈钢 LHP 以模拟 NCG，并在三种典型的蒸发器倾斜度下研究了 LHP 的稳态特性。根据实验结果，可以得出以下主要结论。(1) 无论LHP中是否存在NCG，逆倾时温度最高，顺倾时温度最低。(2) 在三种典型的蒸发器倾斜度下，NCG的存在都会引起温度升高，但在逆向倾斜下NCG引起的温度增量似乎相对较小。(3) NCG引起的温度增量在不同的倾斜度下呈现不同的模式。对结果进行了理论分析：NCG与蒸发器倾斜耦合作用下的温度由蒸发器向补偿室泄漏的热量与返回过冷液体的冷却能力之间的能量平衡决定。随着热负荷的增加，NCG引起的热泄漏的增加与过冷液冷却效果的增强是不一致的。LHP的地面应用应考虑NCG和蒸发器倾斜的耦合效应。NCG与蒸发器倾斜耦合作用下的温度由蒸发器向补偿室泄漏的热量与返回过冷液体的冷却能力之间的能量平衡决定。随着热负荷的增加，NCG引起的热泄漏的增加与过冷液冷却效果的增强是不一致的。LHP的地面应用应考虑NCG和蒸发器倾斜的耦合效应。NCG与蒸发器倾斜耦合作用下的温度由蒸发器向补偿室泄漏的热量与返回过冷液体的冷却能力之间的能量平衡决定。随着热负荷的增加，NCG引起的热泄漏的增加与过冷液冷却效果的增强是不一致的。LHP的地面应用应考虑NCG和蒸发器倾斜的耦合效应。