| Summary: | 碩士 === 臺灣大學 === 應用力學研究所 === 98 === In this study, a new type- Micro-two phase flow concentration gradient generator has been demonstrated. This generator generated droplets with different concentration by Micro-two phase flow generation, separation and combination.
Plastic micro-machining is the method to fabricate the chip in this study. The advantages of this method are reducing fabrication cost and saving time. Due to high integration of chip, it is considered that the Micro-two phase flow chip needs to integrate with the other chips. And the resistance from the other chips wether influences the size of droplet generation must be considered. Since, there are no related researches in literatures. This study discusses the effect of integration resistance by changing the back pressure. To different α(Definition is: Continuous phase channel width/dispersed phase channel) were also discussed. The result showed that the outle pressure did not affect the size of droplet different choice of α. Compare to lteratures, it was found that the outlet pressure control would effective improve the uniformity of droplet size in my own research. For effect of α, the droplet size will decrease as increasing of α. In the continuous phase, for different choice of α, the smaller the droplet size is, the lager the viscosity is. Most of them assumed that the viscosity of dispersed phase flow does not affect the size of droplet in the literatures. However, the result in my own research showed that the viscosity of dispersed phase does not affect the size of droplet. But, the droplet generation type (flow map) has obvious influence. With increasing viscosity of dispersed phase flow, the area of slug flow will decrease. So, the viscosity of dispersed phase flow can not be neglected in the research of droplet formation.
In addition to separation of droplet, there were many methods of droplet separation including active and passive noes. Considering the simplification of chip, the passive method was chosen in this study. The downstream resistance in passive separation method has an extreme influence on separation ratio. Since the control of downstream rsistance from the past literatures can not satisfy the condition in my study, the simple method which is using back pressure controller to adjust the ratio of droplet separation. And, comparing to the maximum ratio of droplet separation 7.5, my study has already successfully made ratio achive 10.8.
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