Abstract:

The pulsating heat pipe is a high-efficiency heat transfer element that is applied in electronic components cooling, energy utilization, etc. Many factors affect its start-up and operation characteristics, such as structure, work material, liquid filling rate, etc. The purpose of this paper was to achieve the asymmetric and staggered structure of pulsating heat pipe by adjusting the length of the local pipeline in the structure of the pulsating heat pipe. At the same time, the pulsating heat pipe heat exchanger device with the corresponding asymmetric structure was designed. Through experiments at 60℃ heat source and different liquid filling rates, the pulsating heat pipe with asymmetric structure was researched. The results showed that the lowest start-up vibration heat source temperature of the pulsating heat pipe rose with the increase of the liquid filling rate. Under very low and high liquid filling rate, the pulsating heat pipe was not easy to start and sustain oscillation phenomenon, and oscillation flow frequency and energy intensity were lower. Under lower liquid filling rate, an effective workpiece movement could not form in the tube due to less workpiece. Under higher liquid filling rate, liquid mass was too much, mass running resistance was larger, and oscillation flow was not easy to circulate in the tube; the temperature difference between pulsating heat pipe evaporation section and condensing section was larger, being more than 15℃, and thermal resistance was larger, with lower equivalent coefficient of thermal conductivity and poor heat transfer performance. In 30% liquid filling rate and 50% liquid filling rate, the temperature difference between both ends of the pulsating heat pipe was smaller, being about 3℃, the thermal resistance was smaller, the equivalent thermal conductivity was higher, the pulsating heat pipe was more likely to achieve isothermal heat transfer, and the optimal liquid filling rate was about 50%.

Key words: pulsating heat pipe, asymmetric, liquid filling rate, heat transfer performance, heat exchanger

摘要：

脉动热管是一种应用于电子元器件冷却和能源利用等领域的高效传热元件，影响其启动和运行特性的因素有很多，如结构、工质、充液率等。本文从整体结构出发，通过调整脉动热管结构中局部管道的长度，实现脉动热管形成非对称、高低交错式的结构形态，同时设计了相应的非对称结构脉动热管换热装置。在热源为60℃下，从不同充液率角度对非对称结构脉动热管进行研究，结果表明：非对称结构脉动热管的最低启振热源温度变化趋势随着充液率的增大而升高。在极低和较高的充液率下，脉动热管不易出现启动和持续振荡现象，振荡流动频率和能量强度都较低。较低的充液率由于工质较少，在管内无法形成有效的工质运动。较高的充液率液体工质过多，工质运行阻力较大，不易在管内循环振荡流动，并且脉动热管蒸发段和冷凝段之间的温差较大，温差都在15℃以上，热阻较大，当量热导率较低，传热性能差。在30％充液率和50％充液率下脉动热管两端温差较小，温差都在3℃左右，且热阻较小，当量热导率较高，脉动热管更易实现等温传热，而最佳充液率为50％左右。

关键词: 脉动热管, 非对称, 充液率, 传热性能, 换热装置