Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2685
標題: 微流道流體混合之可視化實驗與分析
Mixing of Fluids in a Microchannel: A Visualization Study
作者: 陳俊谷
關鍵字: microchannel;微流道;mixing;visualization;混合;可視化
出版社: 機械工程學系
摘要: 
本研究以流場可視化方法為主,並採用微機電系統中的微製造技術,製作微流體晶片,建構簡單幾何形狀的微型流場,作為流場觀察兩種流體混合的元件設備。流道設計以T型為主,並於流道匯合處設置漸縮、漸擴的結構,藉此觀察流場的變化及流體混合的情形。流場觀察則利用CCD攝影機擷取影像,實驗流體採用氫氧化鈉與酚酞分別與酒精調和,原本無色的兩種液體,兩者作用時會產生深紅色,以顏色深淺的一致性作為混合指標,依此建立混合程度量化的方法與技術。由混合程度量化分析的結果中發現,即使以不同顏色(RGB)的影像強度來計算,基本上是一致的。此外,當流道入口端的流量較大時,流體的混合界面會明顯產生週期性擺動的情形,且與流道的幾何形狀尺寸有關,其擺動頻率隨流量而有增加的趨勢。在微型流場中,流體流動包含許多不穩定性的因素,需要進一步分析研究。

This study reports flow visualization results on mixing of two fluids in microfluidics. The fabrication of microfluidic chips adopts the micromachining techniques of MEMS (Micro-Electro-Mechanical System) to construct simple geometric microchannels that provide as the device for observation of mixing process. These channels are mainly designed as T-type, and a structure of convergent and/or divergent is inserted between the intersection of these channels to observe the change of flow field and mixing characteristics. Images of flow field are captured with the CCD camera. Sodium hydroxide and phenolphthalein solutions were dissolved in ethyl alcohol respectively. These two colorless fluids would become red during the mixing process, and the consistency of color intensity is taken as a mixing index. Quantification of mixing efficiency of the fluids is instituted using the mixing indices. It is found that the mixing efficiency determined from the aforementioned method shows an essentially consistent value even employing different color intensities of RGB. In addition, the mixing-interface becomes unstable when the flow rate exceeds a certain value that is associated with geometry of the channel. In general, the instability is enhanced, showing larger oscillation amplitude, for higher flow rate. Details on the interface instability demand further analysis.
URI: http://hdl.handle.net/11455/2685
Appears in Collections:機械工程學系所

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