对单级和双级T形微通道结构中流体的混合规律进行了实验和模拟研究。研究发现,随着流动Reynolds数的增加,微通道内依次出现层流、涡流、卷流3种不同流动状态;在单级T形微通道中,只有当流动处于卷流状态时,混合才得以强化;而对于双级T形微通道结构,流体接触面积增大,流向转变使得当最大尺度的混合通道中出现涡流时,混合即增强。在相同停留时间条件下,双级T形微通道结构中流体混合效率明显高于单级。研究结果充分说明,含有多级T形结构的树状分形仿生网络结构能够极大地强化流体混合,多级T形网络结构是一种高效的微观混合构型。
A series of high-resolution CFD simulations as well as experiments were implemented to investigate the mixing in single stage and double stage T-shaped micro-channel networks.With Reynolds number increasing from 5 to 200,three different flow regimes,namely stratified flow,vortex flow and engulfment flow were observed.In the single stage T-shaped structure mixing efficiency was intensified only when engulfment flow regime was reached.While in the double stage T-shaped network structure,with contact area increasing and flow direction changing,mixing performance apparently improved after vortex flow appeared in the highest stage.Compared with single stage,mixing in the double stage structure occurred earlier.At the same residence time,mixing efficiency was higher in the double stage T-mixer than in the single stage one.Bionic networks containing multi-stage T-shaped micro-channel greatly enhance micro-mixing,and this kind of network is a powerful micro-mixing configuration.