Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/1794
標題: 噴氣面板之長度與寬度對單孔垂直衝擊噴氣流熱傳紐塞數之影響
Effect of Jet Plate Length and Width on the Nusselt Number for a Confined Jet Impinging on a Heated Plate
作者: 蕭文政
Shiao, Wen-Jeng
關鍵字: impinging jet;衝擊噴氣流;heat transfer;stagnation point;Nusselt number;熱傳;停滯點;紐塞數
出版社: 機械工程學系
摘要: 
本篇論文主要在於探討具面板之單孔噴氣流(confined impinging jet)垂直衝擊於等熱通量加熱平板(衝擊面板)上之熱傳現象。實驗中就噴氣流出口之雷諾數(Re)、噴氣流之高度孔徑比(H/d)、噴氣流面板之長度孔徑比(L/d)以及其寬度孔徑比(W/d)等四種因素對平板上停滯點紐塞數之影響進行量測。本實驗所考慮之噴氣流孔徑(d)分別為1.5 mm、3 mm、6 mm及9 mm等四種;噴氣流之雷諾數控制範圍為10,000、15,000及30,000等三種;噴氣流之高度孔徑比為1、2、4及6等四種;噴氣流面板寬度孔徑比為4.17、6.25、6.94、9.72、10.42、12.5、14.58、20.83、25.0、29.17、41.67等十一種;噴氣流面板長度孔徑比為5.5、16.67、27.78、33.33、41.67、83.33、166.7等七種;噴氣流面板與衝擊面板之尺寸大小一致;而加熱片之熱通量則固定在1,000 W/m2。實驗量測之數據經迴歸分析後所得之結果顯示,停滯點紐塞數分別與噴氣流出口之雷諾數之0.638次方、噴氣流之高度孔徑比之-0.3次方、噴氣流面板之寬度孔徑比之-0.044倍之指數與噴氣流面板之長度孔徑比之-0.011倍之指數成正比之關係。
關鍵詞: 衝擊噴氣流,熱傳,停滯點,紐塞數

This work deals with the heat transfer characteristics of a confined circular air jet vertically impinging on a flat plate which was exerted with a constant heat flux. The effects of jet Reynolds number (Re), jet height-to-jet diameter ratio (H/d), jet plate length-to-jet diameter ratio (L/d) and jet plate width-to-jet diameter ratio (W/d) on the stagnation Nusselt number were experimentally investigated. Jet plates with jet diameter of 1.5 mm, 3 mm, 6 mm and 9 mm were individually used in the measurement. Three jet Reynolds numbers, namely, 10000, 15000 and 30000 and four jet height-to-jet diameter ratios, namely, 1, 2, 4 and 6, were individually considered. Eleven jet plate width-to-jet diameter ratios (4.17, 6.25, 6.94, 9.72, 10.42, 12.5, 14.58, 20.83, 25.0, 29.17 and 41.67) and seven jet plate length-to-jet diameter ratios (5.5, 16.67, 27.78, 33.33, 41.67, 83.33 and 166.7) were arranged. For each case, the sing of the jet plate is the same as that of the impingement plate. The heat flux on impingement plate was set at 1,000 W/m2. The measured data were correlated into a simple equation. It was found that the stagnation Nusselt number is proportional to the 0.638 power of the Reynolds number and inversely proportional to the 0.3 power of the jet height-to-jet diameter ratio. It was also found that the stagnation Nusselt number is directly proportional to exp[-0.044(W/d)-0.011(L/d)].
Keywords : impinging jet, heat transfer, stagnation point, Nusselt number
URI: http://hdl.handle.net/11455/1794
Appears in Collections:機械工程學系所

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