不同充液率平板热管性能实验

Characteristic of flat plate heat pipe with different filling ratios

搭建了平板热管测试实验台,对不同充液率下热管性能进行了实验研究,并以最佳充液率的热管为研究对象,分析了加热功率、冷却水温及冷却水流速对热管性能的影响。实验结果表明:充液率为20%和30%时热管在各加热功率下展现了良好的性能,最小热阻为0.18℃/W和0.19℃/W,热导率为8158W/(m·℃)和8540W/(m·℃)。由于沸腾换热滞后性,相较于功率增加,功率减少时热管性能更优,同等加热功率条件下蒸发段温度更低。功率增加和功率减少对热管蒸发段热阻影响较大,而冷凝段热阻几乎不受影响。当冷却水温为17℃和22℃时,热管蒸发段温度比冷却水温为7℃和12℃时蒸发段温度低2℃左右。相较于冷却水温22℃时,冷却水温为17℃时热管蒸发段温度能更快达到稳定值。冷却水流速影响蒸发段温度及达到稳定运行的时间,实验表明热管工作的最佳冷却水流速为5.81g/s。

A test bed on flat plate heat pipe was built in order to study heat pipe performance with different filling ratios. Then the heat pipe with the best filling ratio was taken into account as the research object, the influences of increasing heating power, decreasing heat power, cooling water temperature and mass flow rate on heat pipe performance were analyzed. The results showed that heat pipe with filling ratio of 20% and 30% presented a good performance. The minimum thermal resistance was 0.18℃/W and0.19℃/W, with the maximum effective thermal conductivity of 8158 W/(m ·℃) and 8540 W/(m ·℃),respectively. Compared to heat pipe performance with the increase heating power, the performance with the decrease heating power was better because of boiling hysteresis phenomenon, and evaporation section temperature was lower at the same heating power. The effect on thermal resistance of evaporation section was great with increasing and decreasing heating power, but the thermal resistance of condensation section was almost unaffected. The heat pipe evaporation section temperature with cooling water temperature of 17℃ and 22℃ was about 2℃ lower than that with cooling water temperature of 7℃ and12℃. Compared to cooling water temperature of 22℃, evaporation temperature of heat pipe reached a stable value more quickly when cooling water temperature was 17℃. Thus, the heat pipe performance was best when cooling water temperature was 17℃. Synthesizes evaporation temperature, the time achieving a stable and water pump power consumption, the best mass flow rate for heat pipe was 5.81 g/s.