本文提出一具三層注入方式的矩形小翼對微混合器，流體從兩入口注入後，設計使一種流體自中心而另一種流體自兩側流入主流道，即形成三明治狀的分層，期望藉此增加不同流體間的接觸面積以促進混合。流體在流經流道內的矩形小翼對時，其不同流體間的介面位置會對混合造成很大的影響，為了得到最佳的混合效果，必須仔細探討矩形小翼對的部分幾何尺寸參數。本研究使用數值模擬軟體CFDRC模擬微混合器中流體的混合現象，並配合實驗，觀察螢光反應的圖像以驗證模擬結果。微混合器製程上，先以光微影技術製作微混合器母模，接著以PDMS翻模並與載玻片接合完成微混合器的製作，最後使用雷射共軛焦顯微鏡觀察微混合器中流體的流動現象。本文結果顯示：(一) 矩形小翼對的開口間隙在主流道中心左右交錯排列，使其具有些微不對稱性時，可以得到較佳的混合效果；(二) 矩形小翼對的攻角相對於主要流動方向以低於22.5度為佳，其能有效地引導流體扭曲和產生縱向渦流以促進混合，另外，在高雷諾數時，增加每個矩形小翼對之間的間隙，可使其間之縱向渦流充分地帶動流體以促進混合；(三) 矩形小翼對與流道兩側壁面之間的距離較小時，於高雷諾數能使較多的流體自矩形小翼對的上方間隙流過，加強流體扭曲的現象，於低雷諾數能縮短擴散長度，二者皆使混合效果變好。總之，原型改由具三層注入的方式，並由上述的方針安排五組矩形小翼對後，於各雷諾數之流動條件下的出口皆可得到高混合度(>0.9)。

In this work, we propose and investigate a micromixer which allows three streams of liquids - a core stream sandwiched by two cladding streams - to flow into the main channel with rectangular winglet pairs (RWP) from two inlets. The locations of fluid stream interfaces have significant effect on fluid mixing in a channel with RWP and the increase of fluid interfaces in the proposed mixer is expect to enhance fluid mixing. To take advantage of the proposed design, we have to arrange the RWP appropriately. We examine fluid mixing in the proposed micromixers by numerical simulation and experiment. We use the commercial codes, CFDRC, to simulate the fluid mixing in the micromixer. Comparing the simulation results and fluorescent images shows that the simulation results are reliable. The SU-8 is used to fabricate the mold of micromixers by photolithography. Then, we replicate the mold by PDMS (polydimethysiloxane) and bond the PDMS with a cover glass to complete the fabrication of a micromixer. Finally, we apply the laser confocal spectral microscopy to observe mixing flow in the micromixer. The results show the following trends. (i) When the gap between rectangular winglets of a RWP located slightly asymmetric in the main channel and the centers of the gaps are arranged on both sides of the center of the main channel alternatively, better mixing is achieved. (ii) The RWPs with an angle of attack not greater than 22.5 degrees to the main flow direction may generate longitudinal vortices effectively and lead the distortion of interfaces between fluids to enhance fluid mixing. When the Reynolds number is high, increasing the clearance between the RWPs allows the fully development of the longitudinal vortices downstream which is beneficial to mixing. (iii) When the distance between the RWPs and the channel sidewall is small, more fluids flow through the gap above the top of rectangular winglets for the cases with high Reynolds number and the diffusion length is shorten for the cases with low Reynolds number. These effects enhance fluid mixing. In summary, using the three-stream inlet does enhance fluid mixing and following the above guidelines to arrange five modules of RWPs, the micromixer may achieve a high degree of mixing (>0.9).

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