基于PMMA键合工艺的集成式微混合器设计与实验研究

发布时间：2018-09-18 12:12

【摘要】：作为微流体的新型驱动方式,压电驱动式脉动微混合正在受到国内外学者的广泛关注与研究。其不仅具有重要的学术研究意义,而且在医学检测、有机合成、贵重金属纳米粒子制备等诸多领域具有重要的应用价值。本文提出的基于PMMA键合工艺的集成式微混合器是压电驱动技术的一种新型应用,压电微泵将两种微流体脉动注入,增大了两溶液的接触面积;PMMA键合工艺可以将微流道加工成三维复杂结构,使两溶液在多处形成紊流混合。脉动和被动流道两种混合方式的结合极大的提高了微流体的混合效率。为了制作复杂被动流道,将三维微流体进行片层化设计,基于PMMA的性质对热压键合所需要的有机溶剂进行实验,确定了乙醇溶液作为本次键合的有机溶剂,分别对键合性能影响较大的温度、压力进行了大量实验,实验结果表明,当压力在(1-1.5)MPa之间,温度在(80-90)℃之间能够形成较好的键合效果。本文选择(1.5MPa,80℃)作为集成式微混合器键合工艺的最终参数。通过对单、双腔压电微泵的输出压力与输出流量对比,选择性能相对较高的双腔串联压电微泵作为本混合器的驱动源;分别对双腔串联压电微泵的各个参数进行设计,得到高性能的双腔串联压电微泵。初步确定了两入口流道横截面积为0.6mm×0.6mm,夹角为120°的Y型流道结构。应用ANSYS软件对溶液在平缓直流道以及多拐角流道内的混合进行仿真。从仿真结果可知,溶液的混合效果与雷诺数有较大关系,溶液只在扩散的情况下达到完全混合需要很长的流道,而拐角可以加快溶液的混合。结合本文研究的新键合方法,设计了一种多拐角螺旋式三维流道,确定了集成式微混合器的外形尺寸为70mm×35mm×7.2mm。基于脉动混合方式,本文对产生脉动的条件进行了理论分析,结果表明在Y型流道中,两种液体产生脉动的条件与流道的横截面积、液体的密度、Y型流道的夹角以及Y型流道的速度有关系;溶液输入量过少或过多均不能形成理想的脉动效果,通过改变驱动频率或一次性注入的流量可以形成较好的脉动效果。对Y型入口与部分被动流道进行了仿真分析,结果表明当入口速度为0.05m/s,输出流量为1ml/min,输入频率为50Hz,横截面宽度为0.2mm时有较好的脉动效果。根据仿真结果确定了Y型入口流道的横截面积为0.2mm×0.6mm,其他流道的横截面积为0.6mm×0.6mm,整个微混合器的外形尺寸从初始设计的70mm×35mm×7.2mm优化为50mm×35mm×7.2mm。首先将所设计的集成式微混合器通入水以及不同粘度水-甘油溶液进行了输出性能测试,测试结果表明此混合器对水的最大输出流量为7.3mL/min,对粘度为10mPa.s的水-甘油溶液的最大输出流量为2.3mL/min。之后用水以及水-甘油溶液进行脉动效果测试,通过实验发现当驱动频率为50Hz,输入流量约为1mL/min时,Y型入口处可以产生明显的脉动效果,实验发现本混合器脉动效果受溶液的粘度影响较小而与溶液流量的影响较大。最后用带有荧光粒子的水-甘油溶液进行混合效果测试,实验结果表明多拐角流道有利于溶液之间的混合,脉动注入方式对溶液的混合有明显促进效果,其混合效果远高于无脉动混合效果。
[Abstract]:As a new driving mode of microfluids, piezoelectric pulsatile micromixing is attracting more and more attention from scholars at home and abroad. It is not only of great academic significance, but also of great application value in many fields, such as medical detection, organic synthesis, preparation of precious metal nanoparticles and so on. The integrated micro-mixer is a new application of piezoelectric driving technology. The piezoelectric micro-pump injects two kinds of Micro-fluids pulsatively, which enlarges the contact area between the two solutions. PMMA bonding technology can process the micro-channel into a three-dimensional complex structure, so that the two solutions form turbulent mixing in many places. In order to fabricate a complex passive flow channel, the three-dimensional microfluids were laminated. Based on the properties of PMMA, the organic solvents needed for hot-pressing bonding were experimented, and the ethanol solution was selected as the organic solvents for this bonding. The temperature and pressure advance which had a great influence on the bonding performance were determined. A large number of experiments have been carried out. The experimental results show that the bonding effect is good when the pressure is between (1-1.5) MPa and the temperature is between (80-90). In this paper, the bonding process of the integrated micro-mixer is selected as the final parameter. Double-cavity piezoelectric micro-pump is used as the driving source of the mixer. The parameters of the dual-cavity piezoelectric micro-pump are designed and the high-performance dual-cavity piezoelectric micro-pump is obtained. The Y-channel structure with cross-sectional area of 0.6 mm 0.6 mm and angle of 120 is preliminarily determined. The solution is in a flat direct channel by ANSYS software. The simulation results show that the mixing effect of the solution is related to Reynolds number. It takes a long channel for the solution to mix completely only when the solution is diffused, and the corner can accelerate the mixing of the solution. Based on the pulsating mixing mode, the conditions of pulsation are analyzed theoretically. The results show that in Y-channel, the conditions of pulsation are related to the cross-sectional area of the channel, the density of the liquid, the angle between the Y-channel and the velocity of the Y-channel. The results show that when the inlet velocity is 0.05m/s, the output flow is 1ml/min, the input frequency is 50%, and the input frequency is 50%. According to the simulation results, the cross-sectional area of Y-type inlet channel is 0.2 mm *0.6 mm, the cross-sectional area of other channels is 0.6 mm *0.6 mm, and the shape size of the whole micro-mixer is optimized from 70 mm *35 mm *7.2 mm to 50 mm *35 mm *7.2 mm. Firstly, the integrated micro-mixer is designed. The test results show that the maximum output flow of the mixer is 7.3 mL/min for water and 2.3 mL/min for water-glycerol solution with 10 mPa.s viscosity. When the driving frequency is 50 Hz and the input flow rate is about 1 mL/min, the Y-type inlet can produce obvious pulsation effect. The experiment shows that the pulsation effect of the mixer is less affected by the viscosity of the solution and more affected by the flow rate of the solution. Finally, the water-glycerol solution with fluorescent particles is used to test the mixing effect, and the experimental results show that the multi-corners. The flow passage is beneficial to the mixing of solutions, and the pulsating injection method can obviously promote the mixing of solutions, and the mixing effect is much higher than that of non-pulsating mixing.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ051.71

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