本文以數值模擬與元件實作測試，研製新式Y型被動式微混合器，並罕見以碎形維度定義混合結構之特徵。為能增加流體的混合指標，在主流道內配置三種樹枝分叉狀碎形圖案，各自分叉一重、二重與三重；碎形維度依據盒子理論計算，各為1.222、1.585與1.716。數值模擬部分，計算域網格以ICEM/CFD製作進行前處理，流場計算則採用FLUENT軟體，求解微混合器內的定常流場，再以TECPLOT後處理估算混合效果，雷諾數分別為0.64、6.4與64。元件實作驗證部分，本文利用微機電技術，以SU-8厚膜光阻搭配聚二甲基矽氧烷PDMS翻模製程，成功製作本新式微混合器，並利用螢光顯像與倒立式顯微攝影術拍攝混合情形影像，經MATLAB軟體處理輸出混合指標之數據。數值模擬與實驗結果，均證實本新式微混合器具混合效果：同一種碎形結構下，較小雷諾數(0.64)之混合效果較佳；而雙重分叉之碎形圖案混合效果則優於其它案例。 The present work is to develop a new Y-type passive chaotic micromixer classified by fractal dimension by the numerical and experimental approaches. To enhance the mixing index, three different types of the tree-like fractal patterns were used. The fractal patterns branch for one time (model II), two times (model III), and three times (model IV) have been assigned as the embedded grooves into the main channel of the micromixer. The fractal dimensions are also calculated as 1.222, 1.585, and 1.716 by the box theory. The softwares ICEM/CFD, FLUENT, TECPLOT are used to implement the pre process, field computation, and the post process of the numerical simulation of the new micromixer’s flow field. Three Reynolds numbers of 0.64, 6.4, and 64 are considered. To verify the numerical results, the soft lithography of MEMS technology is used to fabricate the new micromixer. An inverted fluorescence microscopy is used to capture the mixing image of the micromixer, and the mixing index values are derived from the mixing images by MATLAB. Both the numerical and the experimental data show the good mixing of the new device. With the same fractal pattern, the lower Reynold number flow (0.64) has the higher mixing index. The fractal patterns branch for two times (model III) is also better than other cases with high mixing performance.
