具穿孔隔板之180度轉彎通道熱傳實驗研究

Experimental Study of Heat Transfer on the 180-deg Turning Duct with a Perforation Divider

鄭澤明(Tzer-Ming Jeng) ； 曾憲中(Sheng-Chung Tzeng) ； 詹正煥(Cheng-Huan Chan) ； 陳易辰(Yi-Chen Chen)

《建國科大學報》 29卷1期 (2009/10) Pp. 1-21

https://doi.org/10.6995/JCTU.200910.0001

摘要

本研究係以實驗方法探討180度轉彎通道於強制對流冷卻下之熱傳遞特性，180度轉彎通道之內部冷卻構型在工業冷卻之應用非常廣泛，本研究設計將180度轉彎通道其中間分隔具多個穿孔，目的在將第一流道內具較佳冷卻能力之冷流提早引入第二流道，以減少第二流道產生過熱情況，如此可使得機件獲得均勻之冷卻，此外，中間分隔上之穿孔對氣流也具有額外之擾動效果、流經穿孔之旁通氣流與主流交互作用，這都有可能增益整體熱傳能力。本研究採用空氣為冷卻流體，相關變動參數包括雷諾數(Re=1680-13464)與中間分隔穿孔孔徑(d/Dh(下標 h)=0, 0.25, 0.50, 0.75)。實驗結果指出穿孔孔徑d/Dh(下標 h)=0.50 有最佳的熱傳能力，其平均紐塞數比無穿孔者高出7%-46%。

關鍵字

強制對流 ； 180度轉彎通 ； 旁通氣流 ； 實驗

並列摘要

This study experimentally examined the heat transfer characteristics of 180-deg turning duct under forced convection cooling, as the internal cooling structure of 180-deg turning duct is widely applied to industrial cooling. While several perforated holes were separately arranged within the 180-deg turning duct, the cold flow of better cooling capability was guided in the first duct into the second duct in advance, so as to reduce the overheating of the second duct and realize uniform cooling of the machine members. In addition, the centrally separated holes could yield extra turbulence against the air current, and the interaction between bypass air current and mainstream may possibly improve the overall heat transfer capability. This study used air as a cold flow, and the relevant parameters include: Reynolds number (Re=1680-13464) and diameter of central separated holes (d/Dhh=0, 0.25, 0.50, 0.75). The experimental results indicate that, the perforated holes of d/Dhh=0.50 presents an optimum heat transfer capability, with the mean Nusselt number 7%-46% higher than those without perforated holes.

並列關鍵字

forced convection ； U-shape 180-deg turned ； bypass flow ； experiment