二维变形方波微混合器混合效果

设计并制作了多种二维变形方波微混合器,通过荧光观测及标准偏差数值分析,在低Re数(Re≤13.33)时,考察拐角和单元长度对混合器混合效果的影响。结果表明,集成拐角的混合器存在一个临界Re值1.3,当Re<1.3时,混合基于分子扩散,拐角大小对混合效率无影响,混合效率保持在28%左右;当Re>1.3时,可以产生回流,混合效率随着拐角的减小逐渐提高。对于集成6个单元、拐角为45°、单元长度(s)为3132μm的微混合器,在雷诺系数Re=13.33时,混合效率为56%,约提高了1倍;但当拐角与混合单元长度增大时,混合效率明显降低。

Mixing Effect of Two-Dimensional Micromixers Based on the Deformed Square-Wave

A series of two-dimensional micromixers based on the deformed square-wave were designed and fabricated.The effect of the turning angle and unit length on the mixing efficiency at low Reynolds number(Re≤13.33)was investigated by fluorescence observation and numerical analysis of the standard deviation from the pixel intensity distribution.The results indicate that the mixer with the integrated turning angle has a critical Reynolds value of 1.3.The mixture only depends on the molecular diffusion and the mixing efficiencies remained at about 28% when Re<1.3 regardless of the turning angle;the mixing efficiencies increase gradually with the decrease of turning angle due to the recirculation generation when Re>1.3.For the micromixer of six square-wave units with 45° turning angle and 3 132 μm unit length,the mixing efficiency is increased to 56% at Re=13.33.However,the mixing efficiency is decreased with turning angle and unit length increasing.