T形微混合器内的混合特性

Characterization of micro-mixing in T-shaped micro-mixer

以VillermauxDushman快速平行竞争反应为模型体系,研究了宽600μm、深300μm的T形微通道内的微观混合特性,着重考察了不同进出口结构、微通道长度、体积流量比等对微通道内流体微观混合效果的影响.实验结果表明:P啨clet数在7.0×106～2.0×108之间,无返混;体积流量比愈小,离集指数Xs愈小,微观混合效果愈好.不同进出口结构尺寸、体积流量比对微观混合的影响取决于Reyonlds数的大小,Re<Rec时,影响较大,且随Re增加,Xs减小,微观混合效果愈好;Re>Rec时,Xs趋于定值,约为2.7×10-4,接近理想微观混合效果.

The Villermaux-Dushman fast parallel competing reaction was used to determine quantitatively the micro-mixing performance in the T-shaped micromixer with 600μm width and 300μm depth. The flow was almost ideal plug flow in the Reynolds number range 55-1600 and its corresponding Péclet number ranged from 7.0 × 10^6 to 2.0 × 10^8. The effects of inlet and outlet scale, micro-channel length, volumetric flow ratio on the micro-mixing performance were studied in detail. The micro-mixing performance was expressed with segregation index, Xs. The smaller the Xs, the better the micro-mixing. The experimental results showed that Xs increased with increasing volumetric flow ratio at the same Re. There existed a critical Rec under the condition of different inlet and outlet geometric structures. Xs decreased with increasing Re when Re〈Rec, while Xs reached about 2.7 × 10^-4 and remained constant when Re〉Rec, indicating that almost perfect mixing in the T-sharped micro-mixer was achieved.