微流控芯片中电动非牛顿幂律流体的输运机理及实验研究

Microfluidic chip is a novel kind of micro total analytical system, which has broad application prospects in the field of biomedical, analytical chemistry, etc. The transport properties of non-Newtonian power-law fluid of the biological solution is complex in the internal characteristics, limiting the application of microfluidic chips in biological fluids. This project studies the flow- electric-heat-concentration multiphysics fields coupling characteristics and transport properties of the non-Newtonian power-law fluids in microfluidic chips. The main contents include: Rheological properties of blood biological fluid analysis and detection, and improve the constitutive model of the power-law non-Newtonian fluid; Direct coupling numerical simulation of the electrokinetic flow of the non-Newtonian power-law in microfluidic chips using finite element analysis, to understand the microscopic mechanism and macro flow rules of the non-Newtonian power-law in microchannels with complex structures. Study the effects of the non-Newtonian power law fluid transport coefficients and control parameters on the microflow, to reveal the regulation mechanism of the electrokinetic flow of non-Newtonian power-law fluids in microfluidic chips. Testing the electroosmotic flow rate of the non-Newtonian power-law fluid; and the results of theoretical analysis, numerical simulation and experiment are compared each other. This project aims to put forward the optimal design methods on the structures and parameters of the microfluidic chips using the non-Newtonian power-law fluids, ultimately to lay the theoretical and applied foundation for the precise manipulation and detection of various biological fluids in microfluidic chips.

微流控芯片是一种新型的微全分析系统，在生物医学、分析化学等领域具有广泛的应用前景。生物溶液的非牛顿幂律流体内部特性复杂，限制了微流控芯片在生物流体领域的应用。本项目以非牛顿幂律流体为研究对象，对微流控芯片中流场-电场-浓度场-温度场等多物理场耦合特性及流体输运规律进行研究。内容包括：对血液生物流体的流变特性进行分析和检测，完善非牛顿幂律流体的本构模型；采用有限元方法对微流控芯片中非牛顿幂律流体电动流进行直接耦合数值模拟，研究复杂结构微通道内非牛顿幂律流体流动的微观机理和宏观规律；研究非牛顿幂律流体输运系数和控制参数等对微流动的影响状况，揭示微流控芯片中非牛顿幂律流体流动的调控机理。对非牛顿幂律流体的电渗流速度进行实验检测，并将理论分析、数值模拟和实验结果进行对照，提出用于非牛顿幂律流体分析的微流控芯片结构和参数的优化设计方法，为微流控芯片内各种生物流体的精确操控与检测奠定理论和应用基础。

微流控芯片广泛应用于生物样品传输、分析、检测以及微电子元器件的散热，具有尺寸小、成本低、响应快、精度高等特点。生物微流控芯片内流体具有非牛顿幂律流体属性，驱动方式主要为电渗驱动、压力驱动及其混合驱动。本项目主要研究内容为非牛顿幂律流体模型研究、复杂结构微通道内多物理耦合场的机理分析与建模、微通道内非牛顿幂律流体EOF混合的数值模拟与分析、微流控芯片内非牛顿幂律流体的EOF速度检测、交变电场驱动电渗流数值模拟与分析、微混合器的混合驱动与强化等。重要结果包括：解析推导得到了微通道中非牛顿幂律流体电渗流的一般表达式，建立了微通道内电渗、压力驱动以及混合驱动幂律流体的计算模型，数值模拟与分析了五种典型粗糙元（矩形、三角形、圆顶形、正弦粗糙元和准分形粗糙元）对微通道内幂律流体EOF流动特性的影响，提出了一种微通道内离子浓度梯度对电渗流及微混合过程的变量模型，研究了微通道内横向和纵向交变电场驱动EOF的瞬态特性，研究结果对微流控芯片内幂律流体电动流的实验检测有指导意义，还可以为微流体的精确操控如输送、分离、混合等提供理论指导。