Pulsating heat pipes have shown great potential in the field of engineering applications, such as the cooling of microelectronic devices. The correlation between the flow characteristics and the thermal performance of the heat pipe still needs to be further explored. In this paper, the operation state and flow patterns inside pulsating heat pipes with two inner diameters of 1 and 2 mm are experimentally visualised and analysed. The effect of the inner diameter on the thermal performance of heat pipes is evaluated. The results indicate that the operating modes, including small pulsations, bulk pulsations and circulation are sequentially obtained in pulsating heat pipes with the increase of the heat input. The decrease of the inner diameter of pulsating heat pipes results in the capillary instability and the increase of the flow frictional resistance. When the filling ratio is 55%, the thermal performance of a pulsating heat pipe with an inner diameter of 2 mm is better than that of a pulsating heat pipe with an inner diameter of 1 mm.

中文翻译：

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脉动热管两相流与热性能的实验研究

脉动热管在工程应用领域显示出巨大的潜力，例如微电子器件的冷却。流动特性与热管热性能之间的相关性仍有待进一步探讨。在本文中，通过实验对具有 1 和 2 mm 两种内径的脉动热管内部的运行状态和流动模式进行了可视化和分析。评估内径对热管热性能的影响。结果表明，随着热输入的增加，脉动热管依次获得小脉动、大脉动和循环工作模式。脉动热管内径的减小导致毛细管不稳定和流动摩擦阻力的增加。当填充率为55%时，内径为2mm的脉动热管的热性能优于内径为1mm的脉动热管。