In the present study, a joint experimental and numerical study on mass transfer inside vortex-based micro-capillary channels by virtue of chaotic mixing theory is presented. Three different microfluidic chips with different embedded barrier shapes, including cubic, angled cubic, and cylindrical barriers with the same blockage ratio posed behind a couple of symmetric semi-cylinder barriers as mixing promoters inside the channel were designed. To find the optimum geometrical parameters, Optimal Design (OD) method was employed. The results showed that different patterns of vortices can be achieved when the shape of embedded barriers change. The mass transfer or disturbance posed by vortices which were made by streamlines on the local position based on cavity was not only dependent on its vorticity, but also correlates with the fluid stretching based on the Lyapunov exponent theory. Consequently, the application and recognition of suitable vortex patterns play important parts in mixing enhancement. Additionally, three different micromixers with three different embedded barrier shapes produced different vortices sizes at different Re numbers ranging from 0.05 to 93, leading to different mixing performances. The micromixer with middle cubic barriers showed a better mixing trends due to the higher vortex size and lateral fluid velocity. Both experimental findings and numerical results showed that more asymmetric shapes lead to better fluid mixing. It was observed that when the semi-cylinder obstacle radius is greater than 180 µm, large vortices are formed after the obstacles act as hydrodynamic barriers, which in turn promote the cavity-based trapped vortex and fluid stretching.

在本研究中，基于混沌混合理论，提出了基于涡旋的微毛细管通道内部传质的联合实验和数值研究。设计了三种不同的微流体芯片，这些微流体芯片具有不同的嵌入势垒形状，包括在两个对称的半圆柱势垒后面的阻塞率相同的立方势垒，成角立方势和圆柱形势垒，它们是通道内的混合促进剂。为了找到最佳的几何参数，采用了最佳设计（OD）方法。结果表明，当嵌入的势垒的形状发生变化时，可以实现不同的涡旋模式。由基于腔的局部位置的流线引起的涡旋引起的质量传递或扰动不仅取决于其涡旋性，但也与基于Lyapunov指数理论的流体拉伸相关。因此，合适的涡流模式的应用和识别在混合增强中起着重要的作用。此外，具有三种不同嵌入势垒形状的三种不同的微型混合器在0.05至93的不同Re数下产生了不同的涡旋尺寸，从而导致了不同的混合性能。由于较高的涡旋尺寸和横向流体速度，具有中间立方壁垒的微混合器显示出更好的混合趋势。实验结果和数值结果均表明，不对称形状越多，流体混合效果越好。据观察，当半圆柱障碍物半径大于180 µm时，障碍物充当流体动力障碍物后会形成大涡旋，