Please use this identifier to cite or link to this item:
Image Positioning and Visualization Experiments of a Micromixing Chamber on a Rotating Disk
|關鍵字:||Coriolis force;科式力;Visualization Experiments;可視化實驗||出版社:||機械工程學系所||引用:||Anderson, R. C., Bogdan, G. J., Barniv, Z., Dawes, T. D., Winkler, J. and Roy, K., “Microfluidic Biochemical Analysis System,” Proceedings of International Conference on Solid-State Sensor and Actuators, Vol. 1, 1997, pp. 477-480. Atencia, J., and Beebe, D. J., “An Oscillating Ferromagnetic Micropump Utilizing Centrifugal Force,” Proceedings of 7th International Conference on μTAS 2003, eds. Jensen, K. F., and Harrison, D. J., Northrup, MA, Oct. 5-9, 2003, pp. 883-886. Beebe, D. J., Trumbull, J. D., and Glasgow, I. K., “Microfluidics and Bioanalysis System: Issue and Examples,” Proceeding of Annual International Conference of the IEEE Engineering in Medicine and Biology, Vol. 20, 1998, pp. 1692-1697. Branebjerg, J., Gravesen, P., Krog, J. P., and Nielsen, C. R., “Fast Mixing by Lamination,” Proceedings of the IEEE Micro Electro Mechanical Systems (MEMS), San Diego, CA, 1996, pp. 441-446. Brenner, T., Glatzel, T., Zengerle, R., and Ducr||摘要:||
本研究主要針對在旋轉情形之下的微流體晶片，觀察流體混合的現象。實驗採用CNC微機械加工技術，於直徑10 cm的透明光面壓克力碟片上製作微流體晶片。微流體晶片上包含儲存槽、Y型連接流道和圓型混合槽。實驗利用步進馬達旋轉實驗晶片，由旋轉產生的離心力驅動流體，伴隨產生的科氏力於高轉速時可以讓介面摺疊增加混合效益。可視化的取像由光電二極體定位裝置輸出觸發訊號，同步啟動CCD 攝影機擷取影像。實驗流體為三氯化鐵與硫氰化氨，於混合時將由淡黃色變為深紅色的硫氰酸鐵。在相同流道深度條件下，在低轉速(Ω=300 rpm) xjc=4.4 mm的混合效益較xjc=1 mm高20 %，到高轉速下(Ω=1200 rpm)高5-10 %。流道深度由200 μm增加到300 μm，混合效益可以增加10-30 %。其中又因為設計混合槽的構型不對稱，而導致逆時針的混合效益較順時針的好。在可視化影像結果中發現， h=300 μm時，轉速超過540 rpm會在混合槽中產生渦旋，而渦旋的產生會使混合效益提昇。
This study reports flow visualization results of fluid mixing in centrifugal microfluidics. The force acting on the flow field includes the centrifugal and Coriolis forces. The centrifugal force pointing in the radial direction drives the fluids to flow along the channels. The Coriolis force that may introduce the secondary flow pointing in the direction across the channels is able to enhance the mixing efficiency. The microfluidic system was constructed in a PMMA substrate of 10 cm in diameter using a CNC machine. The microfluidic system mainly consists of two reservoirs for fluids of ferric chloride and ammonium thiocyanate solutions, Y-junction microchannels and a circular mixing chamber of 1.5 mm in diameter. The disk is driven by a step motor and the visualization of the mixing is acquired using a CCD (Charge coupled device) camera and a microscope in conjunction with an image positioning unit. The image positioning unit which consists of photodiode and single chip can synchronize the CCD camera when the disk is rotating. Quantification of mixing efficiency is based on the gray scale values resulted from the change of color when the two fluids come to contact each other. At the same rotation speed, the case with the junction-chamber distance (xjc) of 4.4 mm, its mixing efficiency is higher than that for xjc = 1 mm by 5 %. When the channel depth increases from 200 μm to 300 μm, the mixing efficiency will increase about 10-30 %. It is found that sizeable vortices begin to appear for rotation speed at 540 rpm in the 300-μm-depth mixing chamber. The vortices help to increase the mixing efficiency.
|Appears in Collections:||機械工程學系所|
Show full item record
TAIR Related Article
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.