可撓式熱管熱傳性能分析研究

本論文提出一種可撓式熱管的製作方法，並探討其熱傳性能：熱管在絕熱端的部分以高分子材料橡皮管製作，兩端分別連接蒸發端與冷凝端，此材料具有耐熱性良好、工作溫度範圍大、低氣體穿透率和彎曲性佳的特性，此外以外徑6mm的銅管作為蒸發端與冷凝端的主體以有效增加熱傳效果。熱管採用去離子水(DI water)為工作流體，並以200網目的銅網為毛細結構來增加毛細力，依真空度為0.1Torr/0.03Torr和填充3種不同填充率(10%、20%和30%)工作流體的條件下進行實驗，依熱管熱阻值作為評斷熱管性能的依據。實驗結果顯示當填充率為20%時，熱管有較低的熱阻值，因此最佳填充率為20%。本實驗更進一步測試熱管在不同彎曲角度(0 ~135°)下對熱傳性能的影響，實驗結果顯示熱管熱阻值隨彎曲角度加大而升高，當彎曲角度增加時，曲率半徑會隨之減少，這會造成熱管內工作流體的流阻增加並影響蒸氣的流動，進而使得熱管熱傳性能降低。

關鍵字

可撓式熱管；高分子；熱阻

並列摘要

In this thesis, we propose a method to produce a bendable heat pipe, and further examine its characteristics and performance. The heat pipe uses a polymer rubber tube as the adiabatic section to connect the evaporator and condenser. Characteristics of this material include better heat resistance, a broad range of working temperature, lower gas permeability and excellent flexibility. In the study, Copper tubes with an outer diameter of 6mm were used as the evaporator and condenser to enhance heat transfer. Deionized water in the heat pipe was used as the working fluid, and copper mesh with a mesh size of 200 was used as the wick structures to strengthen the heat pipe’s capillary ability. Two vacuum conditions (0.1Torr and 0.03Torr) and three different filling ratios (10%, 20%, and 30%) of working fluid into the heat pipe were applied to investigate the heat pipe’s performance. We used the thermal resistance as the standard for evaluating the performance of the heat pipe. When the filling ratio of the working fluid of the heat pipe is 20%, the lowest thermal resistance value is obtained. So, the optimal filling ratio is 20%. In addition to the proficiency test, the influence of different bending angles (0 ~ 135°) on the pipe’s heat transfer performance was also studied. The experimental results show that the thermal resistance of the heat pipe increases with increasing bending angles. As the bending angle increases, the radius of curvature decreases. The bending angle increases the flow resistance of the working fluid in the heat pipe and disturbs the normal vapor flow, thus leads to reduce heat pipe performance and increased thermal resistance.