影响微槽道流动扩散特性因素的研究

Research on the Influence Factors of Diffusion in Rectangle Microchannel

对压力驱动流下微槽道内流动的不同组分扩散进行了数值模拟。结果表明,雷诺数(Re)是影响微通道内物质扩散的主要因素,合适的 Re 对相应粒子直径物质的扩散很重要。此外,槽道的扩散尺寸(d)与通道深度(w)之比(d/w)对扩散也有一定的影响,当 d/w 较大时,沿w的浓度分布明显为抛物线,此时上下壁面的影响是主要的;反之,当 d/w较小时,沿d、w两个方向的速度分布都为抛物线,上下左右壁面影响都不可忽略。研究结果对微流控系统器件的设计与制造、T-sensor的数据采集与分析具有指导作用。

Multicomponent diffusion in rectangle microchannel for pressure driven flow was simulated numerically. The numerical results show that Reynolds number is the key factor to affect the diffusion in microchannel, suitable Reynolds number is very important to diffusion of species particle with corresponding size. Comparing with the experimental results, we find the numerical results are good agreement with the experimental ones. Furthermore, the ratio of diffusion dimension(d) and channel width(w) also plays certain role in diffusion, the velocity distribution along diffusion dimension is almost the same, and the velocity contribution along channel width is obviously parabola, when the ratio d/w is bigger, so the influences of upper and lower wall are primary. Conversely, when d/w is less, the velocity contributions along both direction are parabola, thereby the influences of all walls (upper and lower, right and left) can not be ignored. The conclusions are helpful to design and fabrication of microfluidic devices and to the data analysis collected from such devices.