Parameter and Investigation of the Polymer Wick Structure Applied to Loop Heat Pipe
Date Issued
2006
Date
2006
Author(s)
Lin, Jun-Yu
DOI
zh-TW
Abstract
The research focuses on the influence of the parameters in polymer wick structure to the performance of the heat transfer in LHP. The parameters on polymer wick structure, including pore radius, permeability and porosity, would promote the design and the qualities and capabilities of LHP. At present, lots if wick structures sinter with the metal powder. When the metal wick structure uses in LHP, the high thermal conductivity coefficient in the metal material causes the problem of the heat transpiration easily, and it is difficult to control well in the parameters of polymer wick structure in the progress. Therefore, polystyrene which is low thermal conductivity coefficient is chosen as the material, and the polymer wick structure is fabricated by salt leaching in biotechnology area. Then, adjusting the size of sodium chloride powder and its percentage in the material, it could not only control the parameter efficiently between the pore radius and the porosity, but also be discussed the relationship of the parameter deeply among pore size, pore radius, and permeability. The experiment is the polymer wick structure is fabricated by salt leaching. The results of the test show that the pore diameter lies in between and , and the porosity is able to be controlled within the range, form 49% to 78%. With different parameters, a formula between permeability and porosity expresses as . Furthermore, this formula would promote both the design of LHP and the prediction of the performance of the heat transfer in the parameter of the wick structure.
What the results of the test reveal is when the smaller the pore radius is, and the bigger the porosity is, the performance of the heat transfer would be much better. Hence, a wick structure with the pore size of , the porosity of 78%, and the permeability of is installed into a LHP system to carry out the test of the performance of the heat transfer. In addition, the above test would compare with the performance of the LHP with a metal wick structure. As the performance test is conducted under the operating temperature of 85℃, and the capacity of the heat transfer in LHP with the metal wick structure approaches 100W, the thermal resistant is 0.711℃/W. however, under the same operating temperature, the maximum capacity of the heat transfer in LHP with polymer wick structure would approach 180W, and its thermal resistant is 0.408℃/W. as a result, with the above comparison, the performance of the heat transfer in LHP with polymer wick structure can increase almost 80%. In short, polymer wick structure, comparing with metal wick structure, has some advantages in the characteristics in its production, such as low manufacturing cost, easy-controlled parameters, perfect processing, and so forth. Moreover, these merits would promote the potential of LHP as much as possible.
Subjects
聚苯乙烯
鹽溶濾法
迴路式熱管
polystyrene
salt leaching
loop heat pipe
Type
thesis
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