This paper reports a parametric study on mixing performance of dean flows in spiral micro-channels using the finite element method. Many important parameters such as the Reynolds number (Re), Peclet number (Pe), flow rate ratio between two species flows (α), and ratio of diffusion coefficient (β) were examined for enhancing mixing efficiency (ηmix). The numerical results matched well with those predicted by the theoretical model. In addition, mixing efficiency of dean flows in the spiral micro-channel generally increased with increasing Re, particularly at low Pe. This is in contrast to results obtained for straight micro-channels with the same channel length. Mixing efficiency (ηmix) was affected significantly by the Pe number ranging from 103 to 4 × 104, and it increases with a decrease in Pe. In addition, ηmix varied remarkably with α, and the worst point, at which the ηmix decreases by 50%, occurs when α is around 2.0. Otherwise, ηmix is shown to be influenced slightly by β. Furthermore, a new generalized correlation was proposed for predicting the pressure drop throughout a spiral micro-channel effectively. These results provide good suggestions for optimizing mixing efficiency of dean flows in spiral micro-channels, which can be used for further biological and chemical analyses.

中文翻译：

---

不同作用下螺旋微通道迪恩流混合性能研究

本文报告了使用有限元方法对螺旋微通道中的 dean 流的混合性能进行的参数研究。检查了许多重要参数，例如雷诺数 (Re)、佩克莱特数 (Pe)、两种物质流之间的流速比 (α) 和扩散系数比 (β)，以提高混合效率 (ηmix)。数值结果与理论模型预测的结果吻合良好。此外，螺旋微通道中迪恩流的混合效率通常随着 Re 的增加而增加，特别是在低 Pe 时。这与具有相同通道长度的直微通道获得的结果形成对比。混合效率 (ηmix) 受 Pe 数的显着影响，范围从 103 到 4 × 104，并且随着 Pe 的减少而增加。此外，ηmix 随 α 变化显着，最坏的点，即 ηmix 下降 50%，发生在 α 大约为 2.0 时。否则，ηmix 会受到 β 的轻微影响。此外，提出了一种新的广义相关性，用于有效预测整个螺旋微通道的压降。这些结果为优化螺旋微通道中迪恩流的混合效率提供了很好的建议，可用于进一步的生物和化学分析。