A study of controlling mixing ratio by using Three-Dimensional crossing microchannels

• Main Authors: Chih-Yu Chiang, 江支佑
• Other Authors: Denz Lee
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/40724842150563896851

碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 97 === How to exact control the mixing ratio of fluid in microchannel is one of the most important issue in microfluid chip. The controlled mixing fraction of fluid can be used to reach the function of sample dilution, synthesis reagents, drug deployment and so on. Therefore, the main purpose of this study was to precise control the mixing fraction of fluid by regulating a simple 3-D crossing microchannel. From the past literatures, which have shown that the aspect ratio and the resistance of channel have significant effect on the fraction of turning flow in 3-D crossing microchannel. By the feature of flow turning and we designed different resistances of the downchannel, the desired mixing ratio may received from the expected outlet of channel. From the numerical results of CFDRC, it can be found that when AR>1 or <0.1, the mixing ratio has significant related to the resistance ratio of the downchannel. However, if the AR=0.45, the resistance ratio of channel showed very little influence on the mixing ratio. Therefore, by varying the outlets of the right downchannel with open or close mode, one may make the mixing ratio changes from 0.1, 0.2 to 0.9. In addition, the formula of fluid resistance was used to obtain the optimal design and some experimental results were realized to verify the fluid phenomena. The results of experiment showed well agree with the numerical ones. Furthermore, a well-uniform mixing fluid can be obtained just combining the designed channel with the 3-D crossing micromixer. The combined design can be expected useful to realize the multi-function of fluid controlling, transportation and mixing to a single chip.