新型分合式微通道混合性能的研究

发布时间：2018-01-13 18:03

本文关键词：新型分合式微通道混合性能的研究　出处：《西北大学》2015年硕士论文　论文类型：学位论文

【摘要】：现代自然科技与工程技术的一个重要发展方式就是微型化,微系统是现代制造技术发展的一个重要方向。微流控芯片则是微系统的一个应用,它针对需要进行的生物或者化学实验研究,使用相应高端微机电加工的方法,以微通道为主体,将实验所用功能单元按照比例缩小到数百微米或者数百毫米的范围内加工到芯片之上,来实现整个实验室的各种反应、分离、检测等功能。微混合器作为微流控芯片上的一个重要部件,其混合效果的好坏对微流控芯片性能有着很大的影响。那么提高微混合器上的微通道混合效率就成为目前研究领域的一个大方向。开发更多类型的微通道的以提高混合效率,满足研究与生产的需要是必不可少的。而本文就微通道的开发这一研究领域,设计了一种新型的分合式微通道结构,该结构可以通过加大流体分流对流程度来增加混合程度,使流体能够达到更加充分均匀的混合。本文通过Fluent数值模拟来对新型微通道混合性能进行研究。首先从分合角度及深宽比这两个方面对新型微通道的结构参数进行了数值优化,结果表明：新型分合式微通道混合效果最好的结构模型是θ=70。,H/W=1,即分合角度是70。,通道宽度是100 u m的微通道。当入口速度Vlm/s时微通道混合器能够达到高效的混合,混合指数小于0.03,特别当速度达到15m/s时微通道出口截面的混合指数已经减小到0.0032,基本达到了完全混合。其次,为了找到操作参数的变化对新型分合式微通道的影响规律,具体从入口速度、扩散系数和运动粘度等方面进行了数值模拟,得到了不同操作参数变化对混合的影响规律,并拟合出了操作参数与通道长度的关联式,对微通道长度的制造与设计都具有很大的指导作用。最后,为了进一步证明新型分合式微通道的混合性能,在相同操作参数的条件下将其与直通道及Z型通道进行了对比,具体包括混合长度、混合时间及压降的分析对比。结果表明,无论在哪种速度条件下,新型分合式微通道达到一定混合程度时需要的混合长度及混合时间都小于另外两种通道,而且混合效率最高；新型微通道的压降在一定速度下虽然高于Z型通道,但相差甚少。总体比较而言,新型分合式微通道的混合性能优于其余两种微通道,压降损耗相差不多,可以作为微流体混合的实际应用。
[Abstract]:Miniaturization is an important development way of modern natural science and engineering technology, microsystem is an important direction of modern manufacturing technology, and microfluidic chip is an application of microsystem. It aims at the biological or chemical experimental research that needs to be carried out, uses the corresponding high-end micro-electromechanical processing method, taking the microchannel as the main body. The functional units used in the experiment are scaled down to hundreds of microns or hundreds of millimeters and processed on the chip to achieve various reactions and separations in the whole laboratory. Micromixer is an important part of microfluidic chip. Its mixing effect has a great influence on the performance of microfluidic chip. Therefore, improving the mixing efficiency of microchannel on micromixer has become a major direction in the field of research. Development of more types of microchannels in order to improve the performance of microfluidic chips. High mixing efficiency. It is necessary to meet the needs of research and production. In this paper, a new type of split-close micro-channel structure is designed for the development of microchannels. The structure can increase the mixing degree by increasing the flow degree of the fluid. In this paper, Fluent numerical simulation is used to study the mixing performance of the new microchannel. Firstly, the mixing performance of the new microchannel is studied from the angle of separation and the aspect ratio of depth to width. The structural parameters are numerically optimized. The results show that the best structural model of the new type of microchannel mixing is 胃 ~ (70) / H / W ~ (-1), that is, the splicing angle is 70. 5. The channel width is 100u m and the mixing index is less than 0.03 when the inlet velocity is Vlm/s. In particular, when the velocity reaches 15m / s, the mixing index of the exit section of the microchannel has been reduced to 0.0032, which has basically reached the complete mixing. In order to find out the influence of the operating parameters on the new micro-channel, numerical simulation was carried out in terms of inlet velocity, diffusion coefficient and kinematic viscosity. The effects of different operating parameters on the mixing are obtained, and the correlation between the operation parameters and the channel length is fitted out, which has a great guiding effect on the manufacture and design of the microchannel length. Finally. In order to further prove the mixing performance of the new micro-channel, it is compared with the straight channel and Z-type channel under the same operating parameters, including the mixing length. Analysis and comparison of mixing time and pressure drop. The results show that the mixing length and mixing time of the new micro-channel are smaller than those of the other two channels under any speed conditions. And the mixing efficiency is the highest; Although the pressure drop of the new microchannel is higher than that of the Z-type channel at a certain speed, the difference is very small. In general, the mixing performance of the new micro-channel is better than that of the other two microchannels, and the pressure drop loss is not much different. It can be used as a practical application of microfluid mixing.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN492

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