Loop Heat Pipe Performance Enhancement With Bilayer Wick Structure
Date Issued
2011
Date
2011
Author(s)
Chen, Zheng-Hong
Abstract
Loop heat pipe (LHP) is a passive two phase heat transfer device, which have ability to transport long-distance, low thermal resistance, and high heat transfer capacity advantages as compared with traditional heat pipe. In recent years, the high heat flux thermal solution requirement follows the electronic device become more powerful and smaller size.LHP developed smaller evaporator size. Therefore, the purpose of this article is to overcome the LHP heat transfer performance decrease sharply when using mono-porous wick in evaporator.
In this study, nickel powder were used to produce bi-layer wick structure by sintered twice. The primary wick is arranged for vapor escape and the secondary wick is for the purpose of managing the fluid flow between the compensation chamber and evaporator. The configuration of wick’s place is in order to separate the vapor and liquid flow that could reduce the heat leakage from evaporator to compensation chamber. According to the present research, it is lake of parametric studies on wick thickness in loop heat pipe. So that, the aim of this study is to understand the thickness effect and find the optimized case.
Experiment result show that the evaporator temperature had significant decrease at the situation of primary wick thickness 1.75mm and the secondary wick thickness increase from 0.75mm to 1.5mm.But when the secondary wick thickness increase from 1.5mm to 2.25mm, there is a sharp decrease in heat transfer performance. So as the result show that there exist an appropriate thickness which have the best heat transfer performance. And in this study, the best secondary wick thickness is 1.5mm.
On the other hand, when the sink temperature set at 10℃and the evaporator temperature not to exceed 100℃, the mono-porous wick have the maximum heat load 600W and total thermal resistance is 0.15℃/W; Bilayer wick structure have the maximum heat load up to 1000W and total thermal resistance is below 0.09℃/W. The bilayer wick structure not only increases at least 400W heat load but also decreases the total thermal resistance about 70%.
Subjects
Loop heat pipe
bilayer wick
heat leakage
high heat flux
Type
thesis
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