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研究生： 葉宜璁
Yeh, Yi-Tsung
論文名稱： 具檔板的鋸齒狀平面微流道中剪切稀化流體的混合
Mixing of shear-thinning fluids in a zigzag planar microchannels with baffles
指導教授： 吳志陽
Wu, C.Y.
學位類別： 碩士
Master
系所名稱： 工學院 - 機械工程學系
Department of Mechanical Engineering
論文出版年： 2010
畢業學年度： 98
語文別： 中文
論文頁數： 272
中文關鍵詞： 微混合器 、剪切稀化流體 、鋸齒狀 、檔板
外文關鍵詞： micromixer, shear thinning fluid, zigzag, baffles
相關次數： 點閱：85  下載：1 
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    • 本文探討剪切稀化流體在具有檔板的鋸齒狀微流道中的混合現象，所使用的剪切稀化流體為羧甲基纖維素水溶液，並採用冪次法則描述剪應力與剪應變率之關係。本研究以商用軟體CFD-ACE+模擬微流道混合器中的三維流動及混合現象，並探討轉彎間的距離、流量、流體的性質及檔板位置對混合效率的影響。實驗過程包含以光微影製程製作母模、用PDMS 翻模、再接合流道。在其中一入口之流體添加玫瑰紅螢光溶液；以雷射共軛焦顯微鏡取得流道中螢光溶液的濃度分佈影像，觀察玫瑰紅螢光溶液之濃度以檢視微流道混合器之混合情形，比較數值模擬與實驗結果，可知二者有足夠的一致性。本研究觀察到下列的現象：(1)在流道轉彎前加入檔板可有效的促進混合；(2)雷諾數越高，混合效率也越高；(3)改變轉彎間的距離可最佳化流體的混合效果；(4)剪切稀化流體與牛頓流體之差異隨雷諾數升高而變大。

    In this work, we investigate the mixing behavior of shear-thinning fluids in a zigzag planar microchannel with baffles. The shear-thinning fluids considered in this work are the aqueous solution of Carboxymethyl Cellulose Sodium. The power-law has been employed for modelling the relation between shear stress and shear rate of the shear-thinning fluid. Then, we apply the commercial package, CFD-ACE+, to simulate the 3-D flow field and mixing behavior in the micromixer. Numerical simulation is performed for various distances between bends, flow rates, fluid properties and the positions of baffles to investigate the effects of these parameters on the mixing behavior in the micromixer. The fabrication process of the micromixer includes applying the photolithography method to fabricate SU-8 mold, replicating PDMS (polydimethysiloxane) mold and bonding the PDMS with a cover glass. Add Rhodamine B to one of the inlet fluids of the micromixer ; the fluid mixing is observed by a laser confocal spectral microscope, Leica TCS SP2. Reasonable agreement of simulation and experiment results is found for the cases considered. From the results of this work the following trends may be observed. (i) Adding buffles to the channel wall before bending enhances the mixing of fluids most significantly. (ii) As the Reynolds number increase, the mixing efficiency increases. (iii) An optimum distance between bends can be found for the mixing of fluids. (iv) The increase of the Reynolds number enlarges the discrepancy between shear-thinning fluid and Newtonian fluid.

    摘要 i Abstract ii 致謝 iii 目錄 iv 表目錄 vi 圖目錄 vii 符號說明 xxiii 第一章 緒論 1 1-1 研究背景 1 1-2 文獻回顧 1 1-3研究動機 2 1-4本文架構 3 第二章 理論與數值模擬 4 2-1 基本假設 4 2-2 統御方程式 4 2-3 邊界條件 5 2-4 無因次分析 8 2-4-1 方程式的無因次化 8 2-4-2 邊界條件的無因次化 9 2-5 數值模擬 10 2-5-1幾何形狀與網格建立 10 2-5-2 求解器 10 2-5-3 後處理 11 2-6 混合程度 11 2-7 微混合器的幾何尺寸 11 2-7-1 無檔板之鋸齒型流道混合器 12 2-7-2 具檔板之鋸齒型流道混合器 12 第三章 微型混合器的製作與觀測 13 3-1 製作流程 13 3-1-1 光罩設計與製作 13 3-1-2 母模製作 13 3-1-3 翻模製作微混合器 15 3-1-4 PDMS成品與管線接合 15 3-2 實驗流程 16 3-2-1 工作流體與微量式注射幫浦 16 3-2-2 影像擷取 16 第四章 結果與討論 17 4-1簡介 17 4-2網格測試與實驗驗證 18 4-3鋸齒型混合器 18 4-3-1 雷諾數在流道幾何參數為2.5的鋸齒型混合器中對混合程度之影響 18 4-3-2 流道幾何參數對鋸齒型混合器混合程度之影響 20 4-3-3 鋸齒型混合器之結論 22 4-4 具有檔板的鋸齒型流道混合器 23 4-5檔板在轉彎前之三轉彎流道混合器 24 4-5-1 雷諾數3 25 4-5-2 雷諾數27 26 4-5-3 雷諾數81 27 4-5-4 檔板在轉彎前之三轉彎流道混合器之結論 30 4-6轉彎前內側、轉彎後外側具檔板之三轉彎流道混合器 31 4-6-1 雷諾數3 31 4-6-2 雷諾數27 32 4-6-3 雷諾數81 34 4-6-4 轉彎前內側、轉彎後外側具檔板之三轉彎流道混合器之結論 37 4-7不同流體對流道混合之影響 38 4-7-1 鋸齒型混合器 38 4-7-2 檔板在轉彎前流道混合器 39 4-7-3 轉彎前內側、轉彎後外側具檔板之三轉彎流道混合器 40 4-7-4不同流體受流道形狀影響之結論 41 第五章 結論與未來展望 43 5-1 結論 43 5-2 未來展望 43 參考文獻 44

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