Study on Circulation Flow in Closed Loop Pulsating Heat Pipe

閉環震盪式熱管之循環流研究

康尚文(Shung-Wen Kang) ； 詹前軒(Chien-Hsuan Chan) ； 蕭百鈞(Pai-Chun Hsiao)

《中國機械工程學刊》 43卷2期 (2022/04) Pp. 79-86

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 (CLPHP) 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. 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, counterclockwise circulation and transition circulation status. The CLPHP thermal resistance was observed to be the least in circulation flow situation.

關鍵字

Pulsating Heat Pipe ； Circulation Flow ； Circulation Period ； Thermal Resistance

並列摘要

本研究利用外徑6 mm、內徑3 mm之玻璃管製作9個折彎數總長1980 mm之閉環震盪式熱管，為了使震盪式熱管更容易達到循環狀態，以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，觀測流體作動情況並計算循環週期與次數。結果顯示熱管在填充率60%、70%、80%，輸入功率200W時將呈現完全循環狀態。循環狀態可分為順轉、逆轉及過渡狀態，實驗顯示，閉環震盪式熱管之熱阻在循環流狀態下最小。