An unsteady microfluidic T-form mixer perturbed by hydrodynamic pressure.
An unsteady microfluidic T-form mixer perturbed by hydrodynamic pressure.
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受流体动压扰动的非稳态微流体 T 形混合器。
DOI：
10.1088/0960-1317/18/4/045015
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Ho,Chih-Ming
中科院分区：
文献类型：
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作者：
Ma,Yanbao;Sun,Chien-Pin;Fields,Michael;Li,Yang;Haake,DavidA;Churchill,BernardM;Ho,Chih-Ming
设计并研究了一种压力扰动驱动的非稳态T型微流控混合器。通过数值模拟和实验研究了混合器的性能。线性斯托克斯方程用于这些低雷诺数流动。采用对流主导扩散方程描述了化学物质浓度不同的两种水溶液在微通道中的非稳态混合。采用速度场的线性叠加求解标量组分浓度方程，大大简化了计算工作。基于低阶的数值代码被认为是不适合模拟的对流为主的混合过程，由于错误的计算耗散。针对对流占优扩散问题，设计了一种具有高数值精度和计算成本有效性的数值算法。在应用于混合模拟之前，通过检查测试用例验证了该数值方案。使用这种新开发的数值算法进行参数分析，以确定最佳的混合条件。数值模拟确定的最佳混合条件有斯特劳哈尔数（St）为0.42。对于T形接头混合器（通道宽度= 196 µm），对于雷诺数小于0.24的流动，在St= 0.42时，约75%的混合可以在小于3 mm的混合距离（即15通道宽度）内完成。通过混合含有黄色和蓝色染料的两种水溶液，对数值结果进行了实验验证。在显微镜下的流场可视化显示的数值模拟和实验结果之间的高度一致性。
An unsteady microfluidic T-form mixer driven by pressure disturbances was designed and investigated. The performance of the mixer was examined both through numerical simulation and experimentation. Linear Stokes equations were used for these low Reynolds number flows. Unsteady mixing in a micro-channel of two aqueous solutions differing in concentrations of chemical species was described using a convection-dominated diffusion equation. The task was greatly simplified by employing linear superimposition of a velocity field for solving a scalar species concentration equation. Low-order-based numerical codes were found not to be suitable for simulation of a convection-dominated mixing process due to erroneous computational dissipation. The convection-dominated diffusion problem was addressed by designing a numerical algorithm with high numerical accuracy and computational-cost effectiveness. This numerical scheme was validated by examining a test case prior to being applied to the mixing simulation. Parametric analysis was performed using this newly developed numerical algorithm to determine the best mixing conditions. Numerical simulation identified the best mixing condition to have a Strouhal number (St) of 0.42. For a T-junction mixer (with channel width= 196 µm), about 75% mixing can be finished within a mixing distance of less than 3 mm (ie 15 channel width) at St= 0.42 for flow with a Reynolds number less than 0.24. Numerical results were validated experimentally by mixing two aqueous solutions containing yellow and blue dyes. Visualization of the flow field under the microscope revealed a high level of agreement between numerical simulation and experimental results.