近年來微流體系統有朝著分析化學與生命科學發展的趨勢，其中不同流體混合對於整個微流體系統的反應效率有舉足輕重的影響。 本文是利用FEMLAB軟體模擬微混合器（T型以及注入型）的流場特性和混合品質，由數值結果發現在T型微混合器(管道寬為600 μm，管道高為300 μm)中依雷諾數的大小，可分成三種截然不同的流場，分別是1) 層化流(stratified flow) (Re<40)，2) 渦流(vortex flow) (40<Re<150)，3) 捲入流(engulfment flow) (Re>150)；其中層化流與渦流的流場對於提升混合品質並無太大的助益，但當流場為捲入流，可以發現混合品質大為提升。 對於注入式微混合器的計算(管道寬與高均為1000 μm，噴嘴寬度70.71–200 μm)，是利用面對面的陣列式微噴嘴來注入流體，此舉最大的好處是能讓欲混合的流體之間接觸面積增加，而由數值結果發現：1) 兩側的微噴嘴尺寸降低有助於提升混合品質，2) 將混合室的寬度降低，使兩流體相遇的距離縮短，其混合品質較高，3) 入口Re增加會使得的混合品質降低，但可有效縮短混合的時間。 Analytical chemistry and life sciences are the recent application trend in the microfluidic system, in which various fluids mixing have profound effect on the reaction efficiency in the microfluidic system. This work performs a numerical study on the flow characteristic and mixing quality of the T-type and injection micromixers. Numerical simulation reveals three distinct flow patterns in the T-type mixer (the channel width is 600 μm and the channel height is 300 μm): 1) stratified flow (Re<40), 2) vortex flow (40<Re<150), 3) engulfment flow (Re>150). While the stratified flow and vortex flow does not enhance the mixing quality, but the engulfment flow leads to significant improvement of mixing quality. For the injection micromixer, simulations are perform for the injection mixer with the channel width and height of 1000 μm and the injection nozzle width various from 70.71 to 200 μm. The utilization of the face-to-face injection nozzle helps the increment of fluid contact area. From simulation results, we found that the enhancement of mixing quality can be achieved either from decreasing the nozzle size or from decreasing the width of the mixing chamber. While increasing the inlet Reynolds number leads to reduce the mixing quality, but it does effectively shorten the mixing time.
