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標題: 具面板多孔噴氣流中噴泉效應與干擾現象對熱傳之影響
Effect of Jet Fountain and Jet Interaction on Heat Transfer for Impinging Air Jets with Staggered Arrays
作者: 賴茂德
關鍵字: fountain effect;噴泉效應;jet interaction;confined impinging jets;stagnation Nusselt number;干擾現象;多孔噴氣流;停滯點紐塞數
出版社: 機械工程學系
本篇論文研究具面板之多孔噴氣流(confined impinging jets)垂直衝擊於等熱通量加熱平板之熱傳現象,主要在深入研究多孔噴氣流中噴泉效應(Fountain effect)與干擾現象(Jet interaction)對停滯點紐塞數(stagnation Nusselt number, Nusg)之影響,並探討在不同高度孔徑比(H/d)下之最佳熱傳孔距孔徑比(s/d)。實驗面板之孔道排列採等孔距交錯式(equilaterally staggered array),孔數為5,孔徑固定為3㎜;孔距孔徑比有4、6、8、12及16等五組;高度孔徑比為2、2.5、3、3.5、4、5及6等七種;噴氣流之全溫度(total temperature, )與室溫控制在24℃;加熱片固定在 ;加熱片之寬度孔徑比(w/d)為29.17;雷諾數( ) 之變化則有30,000、20,000及10,000三種。此實驗量測所得之停滯點紐塞數並以迴歸分析法表示為H/d,s/d與Re之函數。

The effect of jet-to-jet spacing on local Nusselt number for confined circular air jets vertically impinging on a flat plate is investigated. Five jets in equilaterally staggered arrays are considered. The surface heat flux on the plate is 1500 . The jet diameter is 3 mm. Three different jet Reynolds numbers (Re = 10,000 , 20,000 and 30,000) are individually considered. The influence of jet-to-jet spacing, Re and jet height on the stagnation Nusselt number of the center jet is experimentally investigated. The ratio of jet-to-jet spacing to jet diameter (s/d) is in the range of 4 to 16. The ratio of jet height-to-jet diameter (H/d) is in the range of 2 to 6. The ratio of heating width-to-jet diameter (w/d) is 29.17. The jet total temperature is 24℃. An optimum ratio of jet-to-jet spacing to jet diameter is obtained. The existence of the optimum ratio of jet-to-jet spacing to jet diameter is attributed to jet interference before impingement and/or jet fountain. The stagnation Nusselt number is curvefitted as a polynomial with Re, s/d and H/d as the variables.
Appears in Collections:機械工程學系所

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