本研究以流體力學的觀點，發展一氣簾阻截式生物安全櫃，並使用雷射煙霧流場可視化法、壓力診測法及雷射測速儀探討參數變化對流場狀態的影響，因而完成此一新型生物安全櫃之操作特性與範圍。將傳統生物安全櫃之櫃門改裝為可以提供一道二維吹氣噴嘴的機構，並於門檻背後設一道下吸式槽縫，當噴嘴與吸氣槽縫適當的運作時，可使櫃門開口處形成一道空氣簾幕，以此來加強防護櫃內污染物不洩漏至外界的能力。為了瞭解生物安全櫃在運作時，櫃內及櫃門附近的流場型態，使用雷射光頁配合煙霧釋放流場可視化實驗技術進行流場診測研究，分析流場型態，推測造成櫃內污染物洩漏原因，並尋求可能的理想操作模態。吹氣速度、補氣速度、吸氣速度、櫃門開度等四項為影響氣簾式生物安全櫃流場的主要參數。由流場可視化實驗中，可以辨識出，氣簾的行為可以表現為(1)輕微內凹、(2)嚴重內凹、(3)筆直、(4)擺動模態四種特徵模態區域。在櫃內以煙霧釋放器釋放煙霧(模擬污染物的釋出)，可以觀察到，當操作狀態使得氣簾特徵模態為輕微內凹模態時，櫃內與櫃外無迴流現象產生，且櫃內氣流非常平順的被導入門檻後之吸氣槽縫。另外，針對這四種流場特徵模態進行櫃內靜壓量測的結果得知，當操作狀態使得氣簾特徵模態為輕微內凹模態時，櫃內靜壓可以達到輕微低於外界壓力的狀態。基於過去對氣簾式化學氣櫃之研究經驗，在這四種特徵模態中，輕微內凹模態可能會是最佳的操作區域。當操作在輕微內凹模態時，內部污染物質在櫃門靜態、櫃門運動及側風影響的狀態下，可能可以有很好的污染物移除效率以及極低的洩漏。

This thesis describes the experimental analysis of applying the air curtain isolation technique to the containment enhancement of the biological safety cabinet. The sash is remodeled to be able to provide a two-dimensional slot jet and a suction slot is installed just behind the doorsill. By this arrangement, an air-curtain, based on the push/pull principle, can be set up across the sash opening. The laser-assisted flow visualization method, laser Doppler velocimetry, and in-cabinet pressure measurements are performed to identify the characteristic flow modes of the air curtain and the pressure variation in the biological safety cabinet. Four characteristic flow modes of the air curtain, (1) slightly concave curtain, (2) severly concave curtain, (3) straight curtain, and (4) oscillating curtain, are identified. The slightly concave curtain shows stable flow field and smooth flow pattern in the cabinet. The prominent feature is that no recirculation flow structures are found. The in-cabinet pressure measurements show slightly negative pressure appearing in the cabinet when the biological safety cabinet is operated in the regime of slightly concave curtain. According to the previous experience of the research and development of the air-curtain-isolated chemical fume hood, operating the cabinet in the regime of the slightly concave curtain may be a good choice to attain high containment efficiency and low leakage level.

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