内置阻块和挡板微混合器的性能

为提高微机电系统中微混合器的混合效率,基于混沌对流原理,研究了一种流道内布置周期性阻块和挡板结构的被动式微混合器.首先,采用田口分析方法,研究了流道结构参数对流体混合的强化效果,得到微混合器的最优结构参数组合;然后,与现有试验和模拟结果进行对照,验证了数值模拟方法的可靠性;最后,通过CFX数值模拟软件对其内部流场及混合特性进行研究分析.结果表明,倾斜挡板和圆柱形阻块的周期性设置,使微混合器中心处Y方向的速度分量u_y沿X轴作周期性变化,提高了混沌对流强度;当雷诺数超过20时,微流道内产生了一系列复杂的涡结构,大大增加了2种混合流体的接触面积,促使2种流体实现完全混合.

Characteristics of micromixer with periodic blocks and baffles

Based on the principle of chaotic convection, a passive micromixer with periodic blocks and baffles was designed to enhance the mixing performance of the micro-electro mechanical system. First of all, the static Taguchi analysis was taken to evaluate the relative effectiveness of the geometrical parameters of microchannel structure; then, compared with the available experiments and numerical simulation results, it was verified that the numerical simulation method used in this article was reliable; finally, the fluid flow and mixing characteristics of the micromixer were studied by using commercial software ANSYS CFX. The analysis results indicate that the arrangement of periodic blocks and baffles makes lateral velocity u_y periodically change at the center of the micromixer, which leads to the improvement of chaotic convection. When the Reynolds number is over 20, a series of complex expanded vortexes and separated vortexes are generated in the microchannel of micromixer, which leads to the complete mixing of two different fluids.