Experimental investigation on the thermal performance of helium based cryogenic pulsating heat pipe
Experimental investigation on the thermal performance of helium based cryogenic pulsating heat pipe
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DOI：
10.1016/j.expthermflusci.2015.08.024
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发表时间：
2016
影响因子：
3.2
通讯作者：
Dong Xu;Laifeng Li;Huiming Liu
中科院分区：
文献类型：
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作者：
Dong Xu;Laifeng Li;Huiming Liu
对充氦低温脉动热管的热阻、有效导热系数和最大传递功率进行了实验研究。本文采用内径为0.5 mm的不锈钢氦PHP，弯曲成8个平行通道，蒸发器、冷凝器、绝热段长度分别为50mm、50mm、100mm。研制了一种新型的热机械式开关预冷系统，该开关在预冷过程中处于开启状态，在测试过程中处于关闭状态。在不同的热功率、倾斜角度和充液比下进行了试验。在+30°条件下，充液率为70.8%的氦PHP，其有效导热系数为4800 ~ 13000 W/m K，高于铜。随着热功率的增大，热阻先减小后增大，而有效导热系数则相反。有效导热系数和最大传递功率随倾角的增大而增大。此外，氦气PHP具有最大导热效率的最佳充液比，且最佳充液比随热功率的变化而变化。最佳液比本质上是指显热与潜热的合理比例。
An experimental investigation was conducted to study the thermal performance of a cryogenic pulsating heat pipe (PHP) filled with helium in terms of thermal resistance, effective thermal conductivity and the maximum transferred power. The stainless steel helium PHP in this paper with an inner diameter of 0.5 mm was bent to 8 parallel channels, and the lengths of the evaporator, condenser, and adiabatic section were 50 mm, 50 mm, and 100 mm, respectively. A mechanical–thermal switch worked as a novel pre-cooling system for the helium PHP was developed, which was on during the pre-cooling process and off during the test process. Tests were performed with different heat power, tilt angle and liquid filling ratio. For the helium PHP at +30° with a liquid filling ratio of 70.8%, the effective thermal conductivity was 4800–13,000 W/m K, which was higher than that of copper. With the increment of heat power, the thermal resistance decreased at first and then increased, while the effective thermal conductivities were the opposite. The effective thermal conductivity and the maximum transferred power increased with the increment of the tilt angle. In addition, the helium PHP possessed the optimal liquid filling ratio which could make the maximum thermal conducting effectivity, and the optimal liquid filling ratio changed with the heat power. The optimal liquid ratio, by its very nature, meant reasonable proportion of sensible and latent heat.