Operating characteristics of a dual flat-evaporator loop heat pipe for single heat source cooling in any orientation
Operating characteristics of a dual flat-evaporator loop heat pipe for single heat source cooling in any orientation
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DOI：
10.1016/j.ijheatmasstransfer.2021.121146
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发表时间：
2021-06
影响因子：
5.2
通讯作者：
Nguyen Phan;Yuki Saito;N. Katayama;H. Nagano
中科院分区：
文献类型：
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作者：
Nguyen Phan;Yuki Saito;N. Katayama;H. Nagano
本文报道了双平面-蒸发器循环热管（LHP）在任意方向单热源冷却时的工作特性。将双平板式蒸发器的性能与其他单蒸发器的性能进行了比较。设计并制造了两台平板式蒸发器和一台自然对流式冷凝器。用亲水性聚四氟乙烯多孔膜制备毛细管结构，以纯水为工质。在热源的两侧分别设置两个扁平的蒸发器，使热源在六个典型方向上的温度保持在130℃以下。蒸发器/补偿室（CC）平行于水平面，其中一个蒸发器在两个方向上完全位于其CC上方。蒸发器/CCs在其他方向上平行于垂直平面。LHP在所有方向上都以正常的操作模式成功运行。在前两个取向中，不饱和碳碳化合物为较低的碳碳化合物，由于重力作用被液体淹没（深度过冷态）。不饱和CC在其他四个方向上同时含有蒸汽和液体。除了蒸发器和冷凝器之间的高度差异外，这是六个方向上LHP运行特性差异的主要原因。然而，当LHP取向发生变化时，各热负荷下LHP的性能相对均匀。稳态温度可以用我们提出的数值模型来估计。当热源温度低于130℃时，140-W的热量被输送冷却，热阻最低为0.34 K/W。
This paper reports the operating characteristics of a dual flat-evaporator loop heat pipe (LHP) for single heat source cooling in any orientation. The performance of the dual flat-evaporator LHP is compared with that of other single evaporator LHPs used in various orientations. An LHP with two flat evaporators and one natural convection condenser was designed and produced. Capillary structures were made from hydrophilic polytetrafluoroethylene porous membranes, and pure water was used as the working fluid. Two flat evaporators were set on opposite sides of a heat source to maintain the heat source temperature below 130 °C in six typical orientations. Evaporators/compensation chambers (CC) ran parallel to the horizontal plane, in which one evaporator was located completely above its CC, in two orientations. Evaporators/CCs were parallel to the vertical plane in the other orientations. The LHP successfully operated with normal operating patterns in all orientations. In the first two orientations, the unsaturated CC was the lower CC, and was flooded by liquid (deeply subcooled state) owing to gravity. The unsaturated CC contained both vapor and liquid in the other four orientations. In addition to the difference in elevation between the evaporators and condenser, this was the main reason for the difference in LHP operating characteristics in the six orientations. However, LHP performance was relatively uniform at each heat load when LHP orientation changed. The steady-state temperature could be estimated using our proposed numerical model. Below the heat source temperature of 130 °C, 140-W heat was transported and cooled with the lowest thermal resistance of 0.34 K/W.