微尺度下液体流动、传热特性及其应用研究

发布时间：2018-04-23 06:54

  本文选题：微流体 + 微尺度　； 参考：《浙江大学》2016年博士论文

【摘要】：由于微流体设备在高效传热传质、精细高附加值化学品生产等领域广阔的应用前景,有关微尺度下液体流动、传热特性的研究也越来越受到人们的重视。常规尺度下液体的流动、传热特性理论在微尺度下是否适用,在常规尺度下可以忽略的因素在微尺度下是否会对流动、传热产生明显的影响等问题都需要深入分析和探讨。本文研究了不同流体(包括去离子水、离子液体1-乙基-3-甲基咪唑硫酸乙酯水溶液和硝酸钠水溶液)在微尺度下的流动特性,使用COMSOL Multiphysics软件模拟了离子液体水溶液在微尺度下的流动、传热特性,并考察了微流体设备中制备mPEG-PLGA纳米颗粒的过程特性。主要内容如下：1.研究了去离子水在管径范围为44.5-1011 μm,粗糙度(相对粗糙度)范围为0.1-5.2 μm(0.02-4.32%)的三种不同材料(不锈钢SS、聚醚醚酮塑料PEEK和石英FS)管道内的流动特性,得到了雷诺数范围为29-11644的2502个摩擦系数与雷诺数关系的数据点。本文提出了特征参数α来描述微尺度(1-1000μm)与常规尺度(≥1000μm)的偏离程度,基于该特征参数提出了计算微尺度下临界雷诺数的关联式(与实验值的平均绝对偏差AAD为1.9%)以及计算微尺度下湍流区摩擦系数的修正的Moody方程(与实验值的平均绝对偏差AAD为2.4%)。2.研究了浓度分别为10-2、10-4和10-6 mol·L-1离子液体1-乙基-3-甲基咪唑硫酸乙酯([C2mim][EtSO4])水溶液和硝酸钠水溶液在管径范围为44.5-102.5 μmPEEK材料微管(光滑管道)内的流动特性。发现电黏性效应在微管管径大于等于44.5μm时可以忽略,而且离子液体水溶液与普通电解质水溶液的流动特性相同。同时使用COMSOL Multiphysics软件模拟了管径(1-100 μm)和流体浓度(10-2、10-4、10-6 mol·L1)这两个变量对离子液体水溶液流动过程中电黏性效应大小的影响。发现当流体浓度减小到106 mol·L1,微管管径小于等于10μm时,电黏性效应对流动特性的影响大于5%,此时电黏性效应的影响不可忽略。3.测定了离子液体[C2mim][EtSO4]及其相关体系的导热系数,基于二阶Scheffe多项式拟合得到了不同温度、浓度条件下导热系数的关联式。基于拓扑指数法,提出了一个模型来估算离子液体导热系数。然后使用COMSOL Multiphysics软件模拟了管径(1-100μm)和流体浓度(10-2,10-4,10-6 mol·L-1)这两个变量对离子液体水溶液传热过程中电黏性效应大小的影响。发现当流体浓度减小到10-6mol·L-1,微管管径小于等于5μm时,电黏性效应对传热特性的影响大于5%,此时电黏性效应的影响不可忽略。4.使用光刻方法制作了PDMS材料微流体设备,在该设备内稳定层流流动状态下,通过控制流量比率、mPEG-PLGA相对分子量和浓度等工艺条件,制备得到了粒径范围为19-129nm的mPEG-PLGA纳米颗粒。发现微流体法可以实现粒径的较好控制,且得到的纳米颗粒的PDI等性能均优于传统方法制备得到的纳米颗粒。同时在微流体设备中采用布洛芬和姜黄素这两种药物制备了包裹药物的mPEG-PLGA纳米颗粒,得到了较好的药物包裹率、载药量和体外缓释曲线。
[Abstract]:Due to the wide application of microfluidic equipment in the field of high efficiency heat and mass transfer, fine and high value-added chemical production, the research of liquid flow and heat transfer characteristics in micro scale has been paid more and more attention. This paper studies the flow characteristics of different fluids (including deionized water, ionic liquid 1- ethyl -3- methyl imidazole sulfate aqueous solution and sodium nitrate water solution) at microscale, using COMSOL Multiphysics soft. The flow and heat transfer characteristics of the ionic liquid aqueous solution at microscale are simulated and the process characteristics of the preparation of mPEG-PLGA nanoparticles in the microfluidic equipment are investigated. The main contents are as follows: 1. the three different materials of the deionized water in the diameter range of 44.5-1011 mu m and the roughness (relative roughness) range of 0.1-5.2 mu m (0.02-4.32%) are studied. The flow characteristics in the pipes (stainless steel SS, peek plastic PEEK and quartz FS) have been obtained. The data points of the relation between the Reynolds number and the Reynolds number of 2502 of the Reynolds number range are 29-11644. The characteristic parameter alpha is proposed to describe the deviation degree between the micro scale (1-1000 Mu m) and the conventional scale (> 1000 mu m), and the calculation is based on the characteristic parameters. The correlation formula of the critical Reynolds number in microscale (the mean absolute deviation AAD of the experimental value is 1.9%) and the modified Moody equation for calculating the friction coefficient of the turbulent zone in the micro scale (the mean absolute deviation AAD of the experimental value is 2.4%).2., the concentration is 10-2,10-4 and 10-6 mol L-1 ionic liquid 1- ethyl -3- methyl imidazole sulfate ([C), respectively ([C, [C). 2mim][EtSO4]) the flow characteristics of the aqueous solution and the sodium nitrate solution in the tube diameter range of 44.5-102.5 micron microtubule (smooth pipe). It is found that the electric viscosity effect can be ignored when the tube diameter is greater than 44.5 u m, and the flow characteristics of the ionic liquid water solution and the ordinary electrolyte water solution are the same. At the same time, the COMSOL Multiphys is used in the COMSOL Multiphys. The ICs software simulates the effect of the two variables of the pipe diameter (1-100 mu m) and the fluid concentration (10-2,10-4,10-6 mol. L1) on the electric viscosity effect on the flow of ionic liquid water solution. It is found that when the fluid concentration is reduced to 106 mol L1 and the tube diameter is less than 10 mu m, the effect of the electrical viscosity on the flow characteristics is greater than 5%, and the electrical viscosity at this time is more than 5%. The effect of the effect can not be ignored by.3. to determine the thermal conductivity of the ionic liquid [C2mim][EtSO4] and its related systems. Based on the two order Scheffe polynomial fitting, the correlation of thermal conductivity under different temperatures and concentrations is obtained. Based on the topological index method, a model is proposed to estimate the thermal conductivity of ionic liquids. Then COMSOL Multiphy is used. The sics software simulates the effect of the two variables of the pipe diameter (1-100 mu m) and the fluid concentration (10-2,10-4,10-6 mol. L-1) on the electric viscosity effect during the heat transfer of ionic liquid aqueous solution. It is found that when the fluid concentration is reduced to 10-6mol L-1 and the tube diameter is less than 5 mu m, the effect of the electrical viscosity on the heat transfer characteristics is greater than 5%, and the electrical viscosity is at this time. The effect can not be ignored by.4. using photolithography to make PDMS microfluidics. Under the stable laminar flow state, the mPEG-PLGA nanoparticles with a particle size range of 19-129nm are prepared by controlling the flow rate, mPEG-PLGA relative molecular weight and concentration. It is found that the particle size can be achieved by the microfluidic method. The properties of PDI nanoparticles are better than those obtained by traditional methods. At the same time, mPEG-PLGA nanoparticles are prepared by two kinds of drugs, ibuprofen and curcumin, in the microfluidic equipment. The better drug encapsulation rate, drug loading and in vitro release curve are obtained.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TQ021.3
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本文编号：1790911