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|Other Titles: ||Development of medium temperature heat pipe|
|Authors: ||黃勝顯;Huang, Sheng-Sian|
|Keywords: ||陶氏導熱油;燒結式;溝槽式;中溫熱管;熱阻;Dowtherm A;sintered wick;Grooved Wick;medium temperature heat pipe;Thermal resistance|
|Issue Date: ||2016-01-22 15:04:36 (UTC+8)|
|Abstract: ||本研究採用無氧銅作為熱管殼體，外徑8 mm，長300 mm，厚度0.3 mm，分別採用燒結式及溝槽式兩種不同之毛細結構，營造一毛細力將冷卻液體輸送回熱源端吸收熱量，考量殼體與毛細結構的附著力與相容性，採厚度為1.8 mm，孔隙率50 %的銅粉燒結，和厚度為0.25mm，齒數為68齒之溝槽，本實驗使用之工作流體為陶氏高温導熱油(Dowtherm–A)。實驗輸入功率依序為20W、40W、60W、80W、100W，對不同充填量的熱管，在水平與垂直兩種角度下，操作溫度介於200 ~500°C時，進行熱性能的評估與分析。 |
實驗結果指出，在水平狀態下，燒結式充填Dowtherm A 4克(80%)之中溫熱管，傳遞熱量較大，蒸發端與冷凝端溫差較其他充填量小，且在輸入功率為60W後，熱阻低於銅棒，最佳熱阻為1.065°C/W，溝槽式充填量4克(412%)在輸入功率為80W後，熱阻較銅棒低，最佳熱阻為2.113°C/W，可見在水平狀態下燒結式熱性能較溝槽式優越。此外，在垂直狀態下，充填Dowtherm A 4克之燒結式熱管，最佳熱阻為0.563°C/W，傳輸速度約為銅棒的5倍，而溝槽式充填Dowtherm A 4克之熱管，最佳熱阻為0.639°C/W，傳輸速度約為銅棒的4.2倍，結果顯示熱管擺放角度對於Dowtherm-A在不同毛細結構之熱管皆有明顯之影響力。
In this study, the container of the heat pipe used was made of oxygen-free copper, of outer diameter 8mm, length 300mm and thickness 0.3mm. Two kinds of wicks, sintered and grooved, were used to create a capillary force to transfer the working fluid back to evaporator, to absorb heat.
Taking into consideration the adhesion and compatibility of container with sintering substance, the copper powder sintered wick was designed with a thickness 1.8mm and a porosity of 50%. The grooved wick was made with a thickness of 0.25mm with 68 grooves. For the evaluation and analysis of the designed heat pipe, a high temperature working fluid (Dowtherm-A) was used in the study for input power varying from 20W to 100W in 20W increments, different amounts of working fluid, in horizontal and vertical angles, operating in temperatures between 200~500 °C.
Experiments were performed to compare the performance of sintered and groove wick heat pipes in horizontal display angle. Filling Dowtherm-A 4g (80%) in the sintered wick medium temperature heat pipe resulted in a large heat transfer and the temperature difference between evaporator and condenser was found to be smaller than other filling charge. After a power input of 60W, it was observed that the thermal resistance of the heat pipe was lower than that of a copper rod, with the best value 1.065°C/W. In case of the groove wick heat pipe filled with Dowtherm-A 4g (412%), the thermal resistance dropped lower than that of a copper rod after a power input of 80W, with the best value 2.113 °C/W. The thermal performance of the sintered wick heat pipe was found to be superior to the heat pipe with groove wick in horizontal angles.
In the experiments performed for comparison in vertical angles, a transmission speed 5 times that of copper rod was observed in sintered wick heat pipe with Dowtherm-A 4g filling. The best thermal resistance for this case was 0.563°C/W. Whereas for the same filling in groove heat pipe, the best thermal resistance was 0.639°C/W with a transmission speed about 4.2 times that of a copper rod. The result show that display angle had a significant influence on different kinds of wicks with Dowtherm-A filling.
|Appears in Collections:||[機械與機電工程學系暨研究所] 學位論文|
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