Noël Florian, Serra Christophe A, Le Calvé Stéphane
ICPEES UMR 7515, Université de Strasbourg/CNRS, F-67000 Strasbourg, France.
In'Air Solutions, 25 rue Becquerel, 67087 Strasbourg, France.
Micromachines (Basel). 2019 Mar 23;10(3):205. doi: 10.3390/mi10030205.
Following the fast development of microfluidics over the last decade, the need for methods for mixing two gases in flow at an overall flow rate ranging from 1 to 100 NmL·min with programmable mixing ratios has been quickly increasing in many fields of application, especially in the calibration of analytical devices such as air pollution sensors. This work investigates numerically the mixing of pure gas pulses at flow rates in the range 1⁻100 NmL·min in a newly designed multi-stage and modular micromixer composed of 4 buffer tanks of 300 µL each per stage. Results indicate that, for a 1 s pulse of pure gas (formaldehyde) followed by a 9 s pulse of pure carrier gas (air), that is a pulses ratio of 1/10, an effective mixing up to 94⁻96% can be readily obtained at the exit of the micromixer. This is achieved in less than 20 s for any flow rate ranging from 1 to 100 NmL·min simply by adjusting the number of stages, 1 to 16 respectively. By using an already diluted gas bottle containing 100 ppm of a given compound in an inert gas same as the carrier gas, concentrations ranging from 10 to 90 ppm should be obtained by adjusting the pulses ratio between 1/10 and 9/10 respectively.
在过去十年微流控技术快速发展之后，在许多应用领域，尤其是在诸如空气污染传感器等分析设备的校准中，对以1至100 NmL·min的总流速、具有可编程混合比来混合两种气流的方法的需求迅速增加。这项工作对一种新设计的多级模块化微混合器中流速在1⁻100 NmL·min范围内的纯气体脉冲混合进行了数值研究，该微混合器每级由4个300 µL的缓冲罐组成。结果表明，对于1 s的纯气体（甲醛）脉冲后接9 s的纯载气（空气）脉冲，即脉冲比为1/10的情况，在微混合器出口处可以轻松实现高达94⁻96%的有效混合。对于1至100 NmL·min范围内的任何流速，只需分别调整1至16级的级数，即可在不到20 s的时间内实现这一目标。通过使用一个已稀释的气瓶，其中在与载气相同的惰性气体中含有100 ppm的给定化合物，分别将脉冲比调整在1/10至9/10之间，应可获得10至90 ppm的浓度。
