压扁厚度对压扁型烧结式微热管性能的影响

对不同压扁厚度的压扁型烧结式微热管进行了实验研究,优化了压扁厚度为5 mm(真空腔厚度为3 mm)时微热管的工质量,分析了在相同工质量下压扁厚度对微热管轴向温度分布、极限传输功率、各部分温差和热阻的影响.结果表明:对于比完全充满吸液芯时的充液量略少的工质量,压扁厚度只对极限传输功率略有影响;压扁厚度为5、4、3 mm时,极限传输功率分别为40、50、60 W.而对于比完全充满吸液芯时的充液量略多的工质量,压扁厚度的减少会使微热管性能下降,压扁厚度从5 mm减少至4 mm时,热阻从约0.15℃/W提高至约0.20℃/W,压扁厚度为3mm时,微热管失效.文中还对各种实验结果的原因进行了分析,发现压扁厚度主要是通过改变管内工质的分布状况来影响微热管性能的.

Effect of Flattening Thickness on Performance of Flattened Sintered Micro Heat Pipe

An experimental investigation into the heat transfer characteristics of flattened sintered micro heat pipes in different thicknesses was conducted,and the filling ratio of the working fluid was optimized for the pipe with a flattening thickness of 5 mm,namely a vacuum cavity thickness of 3 mm.Moreover,the effects of flattening thickness on the axial temperature distribution,the maximum heat transfer rate(MHTR),the temperature difference and the thermal resistance of the micro heat pipe were analyzed at constant filling ratio.The results indicate that the thickness only has a slight effect on the MHTR when the working liquid quantity is a little less than that fully fills the wick(mc),and that the MHTR reaches 40,50 or 60 W when the thickness is 5,4 or 3 mm,respectively.On the contrary,when the working liquid quantity is more than mc,the thermal performance of the pipe degrades with the decrease in flattening thickness,the thermal resistance increases from 0.15 ℃/W to 0.20 ℃/W if the thickness decreases from 5 mm to 4 mm,and the heat pipe fails at a thickness of 3 mm.Moreover,by analyzing the causes of the above-mentioned findings,it is concluded that the change of thermal performance of the heat pipe is due to the thickness change-induced distribution variation of in-pipe working liquid.