Abstract:

Computational fluid dynamics (CFD) was used to numerically simulate passive mixing of three different types of T-junction micromixers. The relationship between the mixing index and pressure drop loss in a simple micromixer and the inlet velocity, diffusion coefficient and pipe diameter was analyzed. The effects of structural parameters on mixing in a mixer with internal components were also studied. The results show that the mixing index increases with the increase of Reynolds number, Schmidt number and Peclet number, while the pressure drop loss increases with the increase of Reynolds number and decreases with the increase of Peclet number in laminar flow state. After adding ribs and obstacles to the T-junction micromixer, the mixing index increases first and then decreases as Re increases. The longer the rib length, the larger the inner diameter of the obstacle, and the better the mixing effect. However, the corresponding pressure drop is also greater.

Key words: numerical simulation, mixing, microchannel, homogeneous phase, process intensification

摘要：

采用计算流体力学方法（CFD）对三种不同类型的T型微混合器的被动式混合进行了数值模拟。分析了简单微混合器内混合指数和压降与入口速度、扩散系数和管径之间的关系，同时研究了含有内构件混合器中结构参数对混合的影响。研究结果表明，层流状态下，在简单混合器中，混合指数随着Reynolds数Re、Schmidt数Sc和Peclet数Pe的增大而增大，同时压降随Re的增大而增大、随Pe的增大而减小。在T型混合器内加入肋板和障碍物后，混合指数随Re的增大先增大后减小；肋板长度越长，障碍物内径越大，混合效果越好，但相应的压降也越大。

关键词: 数值模拟, 混合, 微通道, 均相, 过程强化