Research on Heat Transfer Performance of the Open-Loop Micro Pulsating Heat Pipe with Self-Rewetting Fluids
Research on Heat Transfer Performance of the Open-Loop Micro Pulsating Heat Pipe with Self-Rewetting Fluids
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DOI：
10.1007/s12217-019-9683-4
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发表时间：
2019-02
影响因子：
1.8
通讯作者：
K. Fumoto;Misaki Sasa;T. Okabe;R. Savino;T. Inamura;Minori Shirota
中科院分区：
文献类型：
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作者：
K. Fumoto;Misaki Sasa;T. Okabe;R. Savino;T. Inamura;Minori Shirota
随着技术变得越来越小型化，极端局部化的散热导致如何防止这些设备过热的挑战。脉动热管是一种基于工质相变的优良冷却装置。对微脉动热管在不同工质下的传热性能进行了实验研究。MPHP由20个平行通道组成，通道由内径为0.8 mm的铜毛细管制成。MPHP填充有作为工作流体的乙醇、去离子水和1-丁醇的水溶液，具有在40-70体积%范围内的不同填充比（FR）。1-丁醇水溶液被称为自再润湿流体，即碳原子数高于4的醇（例如1-丁醇和戊醇）的稀水溶液。自再润湿流体的表面张力随着温度的升高而逐渐降低，在60 °C左右达到最小值，随后在更高的温度下逐渐增加。因此，在相对高的温度下，由于马兰戈尼效应，自再润湿流体流向温度较高的区域。这种流动将改善沸腾现象，这在MPHP的传热机理中是非常重要的。实验结果表明，在自再湿流体的情况下，稳定的振荡运动在MPHP出现在热负荷制度低于与水。此外，具有最高浓度的自再润湿流体的MPHP的有效导热系数高于在高热负荷区域中具有其它流体的MPHP的有效导热系数。
As technology becomes increasingly miniaturized, extremely localized heat dissipation leads to the challenge of how to keep these devices from overheating. A pulsating heat pipe (PHP) is an excellent cooling device based on the phase change of a working fluid. Experiments are performed to investigate the thermal performances of a Micro Pulsating Heat Pipe (MPHP) using different working fluids. The MPHP consists of 20 parallel channels made of a copper capillary tube with an internal diameter of 0.8 mm. The MPHP is filled with ethanol, deionized water and an aqueous solution of 1-butanol as working fluids, with different filling ratios (FRs) in the range 40–70 vol.%. The 1-butanol aqueous solution is known as a self-rewetting fluid, i.e. a dilute aqueous solution of alcohols with a number of carbon atoms higher than four (such as 1-butanol and pentanol). The surface tension of self-rewetting fluids decreases gradually with an increase in temperature, reaching a minimum around 60 °C, and subsequently increases gradually at higher temperatures. Therefore, at relatively high temperature self-rewetting fluids flow towards the regions at higher temperature due to the Marangoni effect. This flow should improve the boiling phenomenon, which is very important in the heat transfer mechanism of the MPHP. The experimental results indicate that, in the case of self-rewetting fluid, the stable oscillating motion in the MPHP arises at the heat load regime lower than that with water. In addition, the effective thermal conductivity of the MPHP with the highest concentration of self-rewetting fluid is higher than that with other fluids in the high heat load regime.