微衝擊冷卻熱傳模式對於微機電系統或高熱流通量之積體電路系統，對微小面積(如CPU)所產生熱點之散熱問題有極高的散熱能力。　　本研究的目是以微機電技術製造寬度5到之25um的微噴嘴，並由微噴嘴提供微噴流流場結構做衝擊冷卻等熱通量加熱晶片之熱傳現象。熱晶片之電路系統則垂直地固定在具有微米級之滑塊與微調鈕的支架上，二者都是固定在水平及防震之光學桌上使得本實驗能夠完成精準之校正與設定，來提供微噴流做微衝擊冷卻熱傳實驗研究。微噴嘴的製作是利用對矽之非等向性濕蝕刻及等向性乾蝕刻機加工方式製作完成出口長4000µm、寬各為25µm、10µm及5µm之三組矩形噴嘴作為實驗量測。
　　微衝擊冷卻熱傳實驗研究，其量測包含自由噴流流場觀察，熱晶片表面局部點及流體溫度的量測。流場觀察則以熱阻絲置於噴流前並加熱後滴上油滴，用以產生煙線，觀測高低速的流場現象，再加以影像擷取機拍攝結果。實驗結果發現當噴嘴出口在低速度條件時，微噴流沿下游發展將保持層流結構直到消失。當出口速度提高時，微噴流沿下游發展將會產生崩潰點使得層流結構演化成完全紊流；隨著噴流出口速度繼續提高時其紊流崩潰點與噴嘴出口之距離則會越加縮短。
　　實驗是以雷諾數(Reynold number)介於6～80之間的自然噴流，衝擊光滑熱晶片，平板至噴嘴距離Z/B介於4～16000之間。當雷諾數升高時，其最大停滯點與噴嘴出口之距離則會越加縮短。故低雷諾數時，其微衝擊冷卻流最大停滯點產生在壁面與噴嘴出口距離為數千倍噴嘴寬度的位置。且當雷諾數固定時，最大Nu值會隨噴嘴寬度縮小而上升，亦代表最大熱傳係數值隨噴嘴寬度縮小而上升。
　　最後，本研究藉由無因次參數(Re、X/B、Z/B及L/B)的引入，很成功的將停滯點、局部點及平均熱傳係數建立經驗關係式，可供微機電系統或CPU散熱設計的參考。

　　Micro-scale impingement cooling process has a very high potential application in cooling a micro-thermal or a high heat flux IC circuits system due to its capability of removing a large amount of heat over a small micro-area.
　　The objective of this study is to design and fabricate a micro nozzle in a size form 5 um to 25 um. This micro nozzle is then used to blow a micro air jet that can be used to impinge and cool a heated thermal chip. The entire thermal chip system is then placed vertically on an optical holder and can be moved vertically in micro-scale by a precision screw on the holder. The structure of this micro jet and the impingement cooling heat transfer over the thermal chip will be studied. The nozzle is made with Si wafer using wet etch ( TMAH、isotropic ) coupled with dry etch ( Anisotropic ) process. This nozzle is rectangular in shape and has 4000 mm in length. The width of the nozzle has three different sizes, i.e. 25 mm, 10 mm and 5 mm, that can be accurately measured.
　　The experimental measurements include flow visualization of the micro jet and impingement cooling heat transfer over the thermal chip. Flow visualization is made by smoke generation that is facilitated by a vertical thin, electrically heated wire coated with oil. The oil is actually supplied by an oil pan on the top of the wire. The jet stream appears to be very stable and maintain its original structure very long until it breaks down on dies out. The breakdown length of the jet becomes shortened when the Reynolds number increases due to the increase in the velocity of the jet.
　　During the impingement cooling experiments the Reynolds numbers varies from 6 to 80, and the nozzle-to-spacings (Z/B) ratio from 4 to 16000. The location for the occurrence of maximum stagnation point Nusselt number approaches the nozzle as the Reynolds number increase.When Reynolds number is kept constant, the Nusselt number and the heat transfer coefficient have increasing with decreases the nozzle width.
　　An attempt was first made to correlate the stagnation point Nusselt number in terms of relevant nondimensional parameters such as the Reynolds number and Z/B. This is done by first normalizing Z/B by dividing Z/B with L/B, i.e. Z/L. The correlation results show that all the stagnation point Nusselt numbers at the same Reynolds number can collapse approximately into a single curve, and these correlations are very successful. Similar kinds of correlations have also been obtained for both the average Nusselt number and the local Nusselt number.

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