Enhancing mixing efficiency in curved channels: A 3D study of bi-phasic Dean-Taylor flow with high spatial and temporal resolution
Enhancing mixing efficiency in curved channels: A 3D study of bi-phasic Dean-Taylor flow with high spatial and temporal resolution
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DOI：
10.1016/j.cej.2023.144342
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发表时间：
2023-07-15
影响因子：
15.1
通讯作者：
Torrente-Murciano，Laura
中科院分区：
文献类型：
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作者：
Pinho，Bruno;Williams，Lindsay M.;Torrente-Murciano，Laura
两相（泰勒流）和弯曲反应器（迪恩流）通常用于通过减少轴向分散和缩小停留时间分布来改善流动系统中的混合。然而，当这两种流态叠加在弯曲通道中的两相流（迪恩-泰勒流）中时，尽管其广泛的实际实施，但由于实验和计算的限制，结果知之甚少。在这项研究中，我们引入了一种新的高效率的计算策略来研究迪恩-泰勒流，提供了非常详细的空间和时间分辨的数据，这种流动状态的流体动力学。这种方法演示了泰勒流的反向旋转涡特性如何失去其对称性，并在弯曲通道中形成三维流型。与纯Dean流和纯Taylor流相比，离心力促进的径向和横向速度分量的出现可以显着增强混合/传质。然而，一定程度的曲率（例如，Dean数> 5）以显著地打破泰勒流涡流之间的屏障。这一新知识的影响是深远的和关键的设计未来的流程，如这里所示的合成铁纳米粒子的窄尺寸分布。
Two-phase (Taylor flow) and curved reactors (Dean flow) are conventionally used to improve mixing in flow systems by reducing axial dispersion and narrowing residence time distributions. However, when the two flow regimes are superposed in bi-phasic flow in curved channels (Dean-Taylor flow), the result is poorly understood due to experimental and computational limitations, despite its widespread practical implementation. In this study, we introduce a novel high-efficient computational strategy to investigate Dean-Taylor flow providing highly detailed spatial and time-resolved data of the fluid dynamics of this flow regime. This approach demonstrates how the counter-rotating vortices characteristics of Taylor flow lose their symmetry and develop three-dimensional flow patterns in curved channels. The appearance of radial and transverse velocity components promoted by centrifugal forces can significantly enhance mixing/mass transfer in comparison to pure Dean and pure Taylor flow. However, a certain level of curvature (e.g.,Dean numbers > 5) is required to significantly break the barrier between the Taylor flow vortices. The implications of this new knowledge are far-reaching and critical for designing future flow processes, as demonstrated here for the synthesis of iron nanoparticles with narrow size distributions.