基于PNP模型的平板微通道非牛顿幂律流体电渗流的数值模拟研究

发布时间：2018-01-10 07:32

本文关键词：基于PNP模型的平板微通道非牛顿幂律流体电渗流的数值模拟研究　出处：《南昌大学》2015年硕士论文　论文类型：学位论文

【摘要】：微流控芯片可以完成液体样品的分离、混合、反应、检测等操作过程,这些过程大部分是需要在微通道中进行的,血液、蛋白质溶液等非牛顿幂律流体常作为生物流体分析的样品进入微通道中,因而对微通道内非牛顿幂律流体的研究具有重大意义。本文基于Poisson-Nernst-Planck(PNP)模型,采用有限元法(FEM)数值模拟了非牛顿幂律流体在微通道内的电渗流(EOF)。主要的研究内容和成果如下:1、基于双电层(EDL)机理,分析了PNP模型平板微通道非牛顿幂律流体EOF的数学模型,并建立FEM离散模型。将PNP模型数值解和诸多假设条件下成立的线性Poisson-Boltzmann模型精确解对比,验证了PNP模型幂律流体EOF的正确性和普适性。2、对薄双电层PNP模型平板微通道非牛顿幂律流体EOF进行了量纲分析和FEM模拟,得出了不同参数对EDL电势和EOF速度的影响规律。研究表明,ζ电势影响EDL电势的大小,正负离子化合价会影响EDL的厚度。稠度系数、外加电场、ζ电势等仅改变EOF速度的大小;幂律指数、正负离子化合价不仅改变速度的大小,而且会影响壁面附近流体速度从零发展到最大值时相对壁面的距离。EOF速度和外加电场、稠度系数、ζ电势等呈幂函数关系,其中稠度系数的指数为幂律指数的负倒数。微通道高度、离子扩散系数对EOF没有影响。这些结果对微通道幂律流体EOF机理的认知和操控技术的改进有指导作用。3、基于PNP模型,数值模拟了幂律流体在矩形、三角形、正弦、分形粗糙元壁面微通道的EOF,讨论相对粗糙度、粗糙元频率等特征对壁面附近EDL电势、流速和微通道流体流量的影响,揭示了粗糙元对EOF的影响规律。这些结果对微流控芯片电渗驱动的理论发展和实际应用具有参考价值。
[Abstract]:Separation, microfluidic chip can complete liquid sample mixing, reaction, detection process, most of these processes are needed in micro channel, blood, protein solution and other non Newton power-law fluid is often used as a biological fluid sample into the micro channel, so the study of micro channel non Newton power-law fluid is of great significance. This paper is based on Poisson-Nernst-Planck (PNP) model, using the finite element method (FEM) numerical simulation of electroosmotic flow of power-law fluid in non Newton in the micro channel (EOF). The main research contents and results are as follows: 1, based on the electric double layer (EDL) mechanism, analyzes the mathematical model of PNP micro channel non Newton power-law fluid EOF, and the establishment of FEM model. Compared with exact solutions of the linear Poisson-Boltzmann model established PNP model numerical solution and many assumptions, validated PNP model of power-law fluid EOF The correctness and universality of.2, thin double layer PNP model of micro channel plate non Newtonian power-law fluid of EOF dimensional analysis and FEM simulation, the effects of different parameters on the EDL potential and the EOF speed. The research results show that the zeta potential of the EDL potential size of positive and negative ions will affect the price of EDL the thickness of the consistency coefficient, the applied electric field, the zeta potential only change the speed of the EOF size; power-law index, positive and negative ion valence not only change the magnitude of the velocity, but also affect the near wall fluid velocity from zero to the maximum value when the relative wall distance and speed of.EOF electric field, the consistency coefficient, a power the function relationship between the zeta potential, the viscosity index of the power-law index of the negative reciprocal. Micro channel height, ion diffusion coefficient has no effect on EOF. These results have guidance to improve the micro channel power law fluid EOF mechanism and cognitive control technology The role of.3, based on the PNP model, the numerical simulation of a power-law fluid in a rectangular, triangular, sinusoidal, fractal roughness wall micro channel EOF, discussed the relative roughness, roughness frequency characteristics of near surface EDL potentials, the micro channel flow velocity and fluid flow effects, the influences of roughness element on EOF. These results have reference value to the theoretical development of microfluidic electroosmotic and practical application.

【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN492

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