本研究提出一具有寬度大於主要流道之擋板與迴流道的微混合器，並探討各種幾何參數下，微混合器的表現。本研究使用商業軟體進行模擬，並配合實驗觀察在微混合器中三維的流動情形。製作微混合器時，使用SU-8光阻塗佈至矽晶圓並曝光以製作母模，使用PDMS翻模並與載玻片接合，最後接上矽膠軟管與微量式幫浦即完成實驗系統。本研究使用共軛焦光譜顯微鏡影像系統觀察流動的現象以佐證模擬結果，將實驗影像與模擬的結果進行比較，發現兩者達到可接受的吻合。經過數值模擬，本文得到以下結論：(1)本研究提出的微混合器，與單純的具擋板且不具迴流道的微混合器相比，前者在較高的雷諾數時能有更佳的混合效果。(2)當雷諾數為81，兩擋板間的距離為2.5倍流道寬之微混合器有最好的混合效果。此外，擋板個數、擋板寬度與迴流道尺寸的影響在本文中也有所探討。

In this work, we propose a micromixer with baffles wider than the main channel and detours, and examine its mixing performance under various geometric parameters. This work uses commercial codes and experiments to observe the three-dimensional flow in the micromixer. To fabricate the micromixer, first we coat the SU-8 photoresist on a silicon wafer and explosure the SU-8 film to get the micro-structure on the wafer. Then we replicate the mold by PDMS, bond the former with a cover glass and consist the micromixer with soft pipes and micro-syringe pump to complete the microfluidic system. The mixing flow is observed by confocal spectral microscope imaging system to validate the simulation. Comparison of the simulation and experiment results shows reasonable agreement. The simulation results show the following trends. (i) The mixing efficiency of the proposed micromixer is better than that of the micromixer with ordinary baffles and without detours for the cases with higher Reynolds numbers. (ii) When Re=81 and the distance between each baffles is 2.5 times of the channel width, the micromixer achieves the highest mixing efficiency. The influence of the baffle numbers, baffle’s width and the size of detours is also investigated.

1. A. Manz, N. Graber and H. M. Widmer, “Miniaturized total chemical analysis systems: a novel concept for chemical sensing,” Sensors and Actuators B: Chemical, Vol. 1, pp. 244-248, 1990.
2. V. Mengeaud, J. Josserand and H. H. Girault, “Mixing processes in a zigzag microchannel: finite element simulation and optical study,” Anal. Chem. , Vol. 74, pp. 4279-4286, 2002.
3. 吳青峰, “渦流與注入流體位置對微型混合器效率之影響,” 國立成功大學機械工程研究所碩士論文, 2004.
4. B. He, B. J. Burke, X. Zhang, R. J. Zhang, and F. E. Regnier, “A picoliter-volume mixer for microfluidic analytical systems,” Anal. Chem. , Vol. 73, pp. 1942-1947, 2001.
5. A. D. Stroock, S. K. W. Dertinger, A. Ajdari, I. Mezic, H. A. Stone and G. M. Whitesides, “Chaotic mixer for microchannels,” Science, Vol. 295, pp. 647-651, 2002.
6. W. R. Dean, “Fluid motion in a curved channel,” Proc. R. Soc. London, Ser. A 121, pp. 402–420, 1928.
7. S. A. Rani, B. Pitts and P. S. Stewart, “Rapid diffusion of fluorescent tracers into Staphylococcus epidermidis biofilms visualized by time lapse microscopy,” Antimicrobial Agents and Chemotherapy, Vol. 49, pp. 728-732, 2005.
8. L. H. Lu, K. S. Ryu and C. Liu, “A magnetic microstirrer and array for microfludic mixing,” Journal of Microelectromechanical Systems, Vol. 11, pp. 462-469, 2002.