Heat Transport Capacity Enhancement of the Biporous Wick for Loop Heat Pipes
Date Issued
2006
Date
2006
Author(s)
Lin, Hsiu-Wei
DOI
zh-TW
Abstract
Loop heat pipe (LHP) which is one of the phase-changing cooling devices could achieve long transport distance, low thermal resistance and high heat transfer. Recently, LHP was miniaturized and its performance was enhanced by improved the wick structure for electronic cooling. The main purpose of this study is to enhance the performance of miniature LHPs by using the bi-porous wick structures, which incorporates the advantages of different pore size distributions.
In the experiments, nickel powders were mixed with the pore former (Na2CO3) to generate the bi-porous wick. To control the pore size distributions, the amount and particle size of pore formers, and the sintering temperature were investigated. Moreover, a two-level experiment-design was made to determine the optimized parameter combination of the bi-porous wick. The results showed that, smaller size and larger amount pore former, and higher sintering temperature would lead to better performance of the bi-porous wick. Among the various parameters, the amount of pore former is the key factor.
The wick parameters of manufactured bi-porous wick, with the pore former content of 40%, the particle size of pore former of 74~88μm and the sintering temperature of 750℃ was measured. The permeability and porosity were found to be 1.034×10-11m2 and 83.1% respectively. The performance test under the heat sink temperature of 10℃ revealed that the heat transfer capacity of mono-porous LHP system was 100W and the thermal resistance was 0.553℃/W, While the bi-porous LHP achieved the maximum heat transport capability of 400W, and the thermal resistance was 0.297℃/W.
Subjects
迴路式熱管
雙孔徑毛細結構
孔徑分佈
loop heat pipe
biporous wick structure
pore distribution
Type
thesis
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