Abstract: Pulsating heat pipe (PHP) is a high efficiency heat transfer device and has unique advantages in cooling electronic apparatus with high heat flux in tiny space.With simple structure, it operates with complex internal rule.The variation of the thermal resistance changing with heating power and filling ratio and the characteristics in nature is analyzed.The dryout characteristic of the PHP is discussed.From experiments on the PHP with four working fluids including water, methanol, ethanol and acetone under different operation conditions, four conclusions can be derived. (1) There is a limitation of thermal resistance for the PHP phase-change convection heat transfer mechanism.And the limitation has little to do with the filling ratio. (2) For different working fluids and filling ratios without dryout phenomenon, the thermal resistances are almost the same under high heating power. (3) The dryout phenomenon only emerges in some of the individual pipes in the evaporation section periodically.When the heat load is further intensified, dryout will occur in more pipes in the evaporation section and last for a longer time, but the temperature will not increase rapidly so that the PHP will not be burned out. (4) Before valid oscillation starts, the experimental data show that the decrease of thermal resistance may slow down or change to increase first and then decrease, with an inflection point, which is different from the almost linear decrease described in literature.This work provides a reference for establishing theoretical model and understanding the heat-transfer of pulsating heat pipe.

Key words: pulsating heat pipe, characteristics of thermal resistance, dryout phenomenon

摘要： 振荡热管作为高效传热元件,在解决微小空间而热通量较高的元器件散热方面具有独特的优势。虽然振荡热管结构简单,但其内部运行规律多变复杂,目前还处于探索研究阶段。通过对实验结果的分析,得到随加热功率和充液率改变振荡热管的热阻变化规律,探讨了不同工况所对应的传热机理;同时还对振荡热管的烧干特性进行了分析和研究。所做工作为建立振荡热管理论模型、认识其传热规律提供参考。

关键词: 振荡热管, 热阻特性, 烧干现象