圆柱阵列微通道中复杂流体的流动行为研究

Study on Flows of Complex Fluids in Microchannels with Pillar Array

具有圆柱阵列的微通道可利用法琳效应产生的无细胞血浆层(尾迹)来放大血液等复杂流体的流动行为,从而更好地操控流体或简便地预测流体的特性。以血液作为典型的复杂流体,系统考察了静态和动态血细胞浓度与减阻剂等因素对圆柱阵列微通道中尾迹宽度和血细胞分布的影响规律。血液样品流经圆柱阵列后产生尾迹宽度随着血细胞浓度的增大而减小甚至消失。在考察的1.7%-70%血细胞浓度范围内,可根据两者的定量关系由尾迹宽度得出血细胞浓度的大小。微量聚环氧乙烷(PEO)减阻剂的加入使粘弹性作用起主导作用,血细胞向壁面发生迁移,并且出现复杂的分层分布。研究结果有望为微通道中非牛顿流体等复杂流体各组分的分离和操控提供新的思路。

The flowing behaviors of the complex fluids such as blood sample may be amplified through cell-free plasma layer（i.e. the wake） induced by F？hr？us-Lindqvist effect in the microchannels with pillar array, which may better manipulate the fluids and easily predict the fluid property. Taking the diluted blood as an example, the effects of factors such as static and dynamic cell concentration as well as the addition of drag reducer on the wake width and the distribution of blood cells in the microchannels are systematically investigated in the study. The wake width of blood sample generated along the pillar array decreases and even disappears with the increasing cell concentration. In the investigated cell concentration range of 1.7%- 70%,the cell concentration value can be determined by the wake width according to their quantitative relationship. Compared with the dominant lift force in the blood sample without polyethylene oxide（PEO）, the viscoelastic effect becomes dominant in that with trace PEO. The blood cells migrate to channel walls and the complex layered distribution manifests. The results will provide the new ideas for component separation and manipulation of complex fluids such as non-Newtonian fluid in the microchannels.