结构参数对布置窄缝和挡板的微混合器内流体流动和混合的影响

Effect of structural parameters on fluid flow and mixing characteristics in micromixer with gaps and baffles

基于混沌对流原理设计了一种布置窄缝和挡板结构的被动式微混合器,并采用三维数值模拟和可视化实验对该微混合器内流体流动与混合特性进行了研究。窄缝和挡板的共同作用使微混合器水平面内形成了扩展涡和分离涡,垂直流动方向的截面内形成了对称的反向旋涡,多维度涡系显著提高了混合效率。窄缝和挡板的结构尺寸对流体流动和混合有重要影响。综合考虑混合强度和压降,利用场协同原理分析窄缝宽度、窄缝长度、挡板高度对微混合器综合性能的影响并得到了不同Reynolds数条件下的最优结构参数。

A passive micromixer with gaps and baffles was proposed based on the principle of chaotic mixing and the fluid flow and mixing characteristics in the micromixer were studied by three-dimensional numerical simulation and visualization experiment. Expanded vortices and separated vortices were generated in the horizontal plane and counter-rotating vortices formed in the cross-sectional plane perpendicular to the flow direction by the combination of gaps and baffles. The mixing efficiency was significantly improved by the multidirectional vortices. The geometrical parameters of gaps and baffles had great effect on the fluid flow and mixing. Based on the consideration of mixing efficiency and pressure drop, the effect of gap width, gap length and baffle height on the comprehensive performance of the micromixer was investigated by the field synergy principle. The optimal structural parameters were presented with varying Reynolds number.