Heat Transport Characteristics and Operating Limit Expansion of Oscillating Heat Pipe

为了在空间环境中使用振荡热管，除了要有高的性能外，在各种条件、温度和热输入范围内工作是非常重要的。在这项研究中，将灯芯插入到OHP(I.D.=φ1.5 mm)中以扩大这一条件的范围。邪恶的OHP在更高的输入功率范围内工作得很好，而没有芯子的OHP则不起作用。但在中等范围内，有害OHP的有效导热系数变得低于正常OHP。如果芯子以对称的形式插入，则不会出现循环流动，OHP效果不佳。尽管直径为2 mm的普通OHP不起作用，但邪恶的OHP运行良好，表现出良好的性能。在垂直底部加热作业中，OHP表现出更好的性能，在以乙醇为工质的水平作业中，OHP表现出更好的性能，在整个OHP的半长处都有芯。通过将绝热截面长度从270 mm延长到1000 mm，考察了有无灯芯的OHP性能。在水平操作中，邪恶的OHP工作良好，绝热段长度为270 mm或500 mm时表现出良好的性能。此外，从空间应用的角度出发，在较低的温度范围内研究了以氨为工质的热泵系统。在立式操作中，无芯氨水OHP表现出比乙醇OHP更高的性能。在水平操作中，邪恶的氨OHP工作良好，但在较高热输入功率的情况下不稳定。

For use of oscillating heat pipes (OHPs) in a space environment, in addition to a high performance, it is very important that they work in a wide range of conditions, temperature and heat input. In this research, wick was inserted to the OHP (I.D.=φ1.5mm) to expand this range of conditions. The wicked OHP worked well at a range of higher input power, where a OHP without wick didn't work. But at a middle range, the wicked OHP's effective thermal conductivity became lower than that of the normal OHP. If wicks were inserted in a symmetrical configuration, circulating flow didn't occur and OHP didn't worked well. Although a normal OHP of 2mm I.D. didn't work, the wicked OHP worked well and showed a good performance.The OHP showed a better performance both without a wick in a vertical-bottom-heating operation, and with a wick at half-length of overall OHP in a horizontal operation using ethanol as the working fluid. The OHP performance with or without wick was investigated by extending the adiabatic section length from 270 to 1000 mm. In a horizontal operation, the wicked OHP worked well and showed a good performance with the adiabatic section 270 or 500 mm in length. Furthermore, for practical space use, the OHP using ammonia as the working fluid was investigated in the lower temperature region. The ammonia OHP without a wick showed higher performance than the ethanol OHP in a vertical operation. In a horizontal operation, the wicked ammonia OHP worked well, but unstably in the case of higher thermal input power.