矩形水平管道內加熱晶圓由浮力所驅動空氣問合對流與傾斜晶圓使流場穩定之觀測與溫度量測

Abstract

本篇論文對於底部鋪設圖形國熱板的水平矩形管道內空氣強制對流在空間和溫度場上形成複雜的渦流結構和熱力學特性，配合流場可視化的技術和溫度量測加以詳細探討。為了包含過渡過程中的穩流，週期和非週期流場特性，雷諾數（Reynolds number ）的範圍由100到1000，雷利數（Rayleigh number）由1.35×105到8.1×105。在低浮力－慣性力比的條件下，流場可視化所得到的結果顯示在測試段前半部靠近頂板之處存在著迴流，並且在中央垂直平面附近靠近側壁的地方存在著一對不對稱的迴旋渦流。在較高的浮力－慣性力比的情況下，測試段後半段出口端處的中央垂直平面附近生成一對新的迴旋渦流。除此之外，在此所形成的渦流結構比較結實也較大。然而，當浮力增加，流場會由穩定轉變成不穩定的狀態。將所得暫態的溫度歷程整理成流場組織圖之後，發現到當雷諾數小於等於200時，流場屬於次臨界過渡狀態；而當雷諾數大等於300時，則屬於超臨界過渡狀態。在不穩定流場中，靠近X=b/2 附近上下游間迴旋渦流的內層邊界之內存在形成溫度震盪振幅最強的位置。最後，利用傾斜的加熱板來穩定流場。傾角可由 0° 增加到6°。

Combined flow visualization and temperature measurement were carried out in the present study to investigate the complex spatial and temporal vortex flow structures and thermal characteristics in a forced air flow through a horizontal rectangular duct with a heated circular copper plate laying on the duct bottom. Results were obtained for the Reynolds number ranging from 100 to 1000 and Rayleigh number ranging from 1.35×105 to 8.1×105 covering the steady,time periodic and n0periodic flows. The results showed the presence of the returning flow in the entry half of the duct of asymmetric flow recirculations near the duct sides around the central vertical plane at x=b/2 and a pair of asymmetris flow recirculation near the duct sides at a low buoyancy-to -inertia ratio. At a higher buoyancy-to -inertia ratio a new flow recirculation appears in the exit half of the duct near the central vertical plane.In addition , the qortex flow is stronger and the recirculation cells are bigger . Moreover, at increasing buoyancy flow transition from stable to unstable states was noted. A flow regime map was giventoi delineate the temporal state of the flow. The results suggested the subcuitical folw transition for Re<=200 and supercritical flow transition for Re>=300. Moreover.the temperature oscillation in the unstable flow was strongest in the interboundary between the upstream and downstream flow recirculations near the plane x=b/2. Finally, the inclination of the heated plate was found to produce significant flow stabilization . Angle is tilted from0° to 6°．