平板式小型环路热管的实验研究

设计一套蒸发器尺寸为74 mm(D)×14 mm(H)的平板式小型环路热管(mLHP)，工质为甲醇，冷凝方式采用冰水混合物冷却，研究其换热性能。实验表明，该环路热管能够实现重力和无重力辅助启动。倾角为18 °、充灌率为60%时，热负荷从20 W增加到140 W，整个环路热管热阻从2.58 ℃/W减小到 0.44 ℃/W 。无重力辅助启动时，mLHP能够散去130 W的热量而壁面温度低于80 ℃。当热负荷一定, 无重力辅助启动时的蒸发器壁面温度高于重力辅助启动时的壁面温度。在保证系统启动的工质裕量前提下，减少工质充灌量有利于降低蒸发器壁面温度。mLHP运行存在低热负荷区和高热负荷区，在低热负荷区，蒸发器和补偿腔温度随着热负荷的增加降低；在高热负荷区，蒸发器和补偿腔温度随着热负荷的增加升高。

Experimental Study on Miniature Loop Heat Pipe with Flat-Plate Evaporator

A miniature Loop Heat Pipe (mLHP) with flat disk shaped evaporator with dimension of 74 mm in diameter and 14 mm thick is designed to study its performance of heat dissipation. Its working fluid is methyl alcohol and the condensation type is ice water cooling. The study indicates that this mLHP has high performance of heat dissipation, an could start up with and without gravity assistance. Given that the tilt angle is 18 ° and the liquid charge ratio is 60%, the thermal resistance of the whole heat pipe lies between 2.58 ℃/W and 0.44 ℃/W for heat loads in the range of 20 W to 140 W. The mLHP is able to transfer a heat load of 130 W without gravity assistance while the temperature of the evaporator wall is below 80 ℃. At constant heat load, the temperature of evaporator wall without gravity assistance is higher than that with gravity assistance. Under the precondition of leaving enough working fluid to keep the system to start up successfully, reducing the liquid inventory of mLHP conduces to lowering the temperature of the evaporator wall. There are two regions of low heat loads and high heat loads when the mLHP operates properly. In the region of low heat loads, the temperatures of the evaporator and the compensation chamber fall with the augment of heat loads, and the trend is opposite in the region of high heat loads.