封閉迴路式震盪熱管之循環流研究

Study on Circulation Flow in Closed Loop Pulsating Heat Pipe

詹前軒(Chien-Hsuan Chan)

指導教授 ： 康尚文

淡江大學/工學院/機械與機電工程學系碩士班/碩士(2010年)

https://doi.org/10.6846/TKU.2010.00965

摘要

本研究是利用外徑6mm、內徑3 mm之玻璃管製作9個折彎數總長1980mm之震盪式熱管，為了使震盪式熱管更容易達到循環狀態，故製作水冷系統為冷凝器並控制溫度在35°C，在不同工作流體填充率(20%、30%、40%、50%、60%、70%及80%)、及不同輸入功率(40W、80W、120W、160W、200W)下評估整體熱阻值。
利用數位攝影機拍攝影片，分析記錄震盪式熱管內流體循環之週期，為了方便觀察流體的動向，本實驗加入保麗龍球來確認流體流動之方向。在不同填充率下觀測流體作動情況並計算循環週期與次數，此外針對傾斜角度對於震盪式熱管性能之影響加以探討及分析。
結果顯示熱管在填充率60%、70%、80%，輸入功率200W時將呈現循環狀態。循環狀態可分為順轉、逆轉及過渡狀態，且以填充率80%之週期最短，而在每次循環中逆轉的次數會多於順轉的次數。震盪式熱管於傾斜角45°時性能最佳且循環週期較短，推測主要乃受到重力影響所致。

關鍵字

震盪式熱管 ； 循環流 ； 循環週期

並列摘要

This research utilized 6 mm outer diameter and 3 mm inner diameter glass tubes to manufacture 9 turns closed loop Pulsating Heat Pipe(PHP) with a total length of 1980mm. For achieving the loop circulation easily, a water cooling system kept at 35 ° C was used as the condenser. The experiment was conducted to evaluate the thermal resistance under different fluid filling ratios (20%, 30%, 40%, 50%, 60%, 70% and 80%), and at a series change of heat inputs (40W, 80W, 120W, 160W, 200W).

Through a digital video camera, the visualization experiment was carried out to observe the circulation flow period in the PHP. A styrofoam ball was designed to put into the tube for a better observation and a correct estimation of fluid flow direction. Circulation times and circulation period were observed and calculated from different filling ratio tests. We also analyze the effect of inclination angles to the performance and circulation period in the PHP.

The results showed that PHP reached fully circulation under the filling ratio of 60%, 70%, and 80%, at an input power of 200W. The circulation can be categorized into clockwise circulation, counter-clockwise circulation and transition circulation status. The shorter circulation period happened as filling ratio was 80%. We also found that there were more counter-clockwise circulation occurred in each experiment. Due to gravity effects, better performance and shorter period took place when the inclination angle was 45 °.
Key words: pulsating heat pipes, PHP, circulation flow, circulation period

並列關鍵字

Pulsating Heat Pipe ； Circulation Flow ； Circulation Period

參考文獻

[22] 林玉興，「震盪式熱管之製造與分析」，博士論文，淡江大學機械與機電工程研究所，民國九十七年。

[25] 陳冠廷，「應用類神經網路預測震盪式熱管之熱性能」，碩士論文，淡江大學機械與機電工程研究所，民國九十八年。

[7] T. N. Wong, B. Y. Tong, S. M. Lim and K. T. Ooi, “Theoretical Modeling of Pulsating Heat Pipe,” Proc. 11th International Heat Pipe Conference, Tokyo, Japan, pp. 159-163 (1999).

[8] B. Shafii, A. Faghri and Y. Zhang, ”Thermal Modeling of Unlooped and Looped Pulsating Heat Pipes,” Journal of Heat Transfer, Vol. 123, pp. 1159-1172 (2001).

[10] S. Khandekar, N. Dollinger and M. Groll, “Understanding Operational Regimes of Closed Loop Pulsating Heat Pipes: An Experimental Study,” Applied Thermal Engineering, Elsevier Science, Vol.23, pp. 707-719 (2003).