抗高过载微流体惯性开关

基于微连通器结构,提出了一种使用盐水(Na Cl溶液)作为工作流体且具有高的抗过载能力的微流体惯性开关。分析了液滴的分离机理,设计了开关的流道结构。然后,对开关进行了理论分析,建立了开关模型。最后,利用流体动力学仿真和样机实验相结合的方法,对开关结构和功能进行了验证。验证结果显示:在幅值为30 000 g阶跃型加速度作用下,开关的工作流体仍未发生分离,加速度的幅值与开关响应时间相关。另外,开关样机能够使盐水液面形成高度差,样机的静态加速度阈值为134.6 g~152.3 g,非常接近其理论计算的加速度阈值142.7 g。得到的结果表明,采用的微连通器结构能够极大地增强微流体惯性开关的抗液体分离能力,能够对加速度幅值进行区分,并实现闭锁功能,同时显示了高的抗过载能力。

A microfluidic inertial switch with response characteristics to high acceleration

On the basis of micro communicating vessels, a novel microfluidic inertial switch with excellent response characteristics to a high acceleration over 30000g was proposed. Brine was selected as the working-fluid due to its conductivity and non-toxicity. The mechanism of droplet separation was discussed, and the channel structure of the switch was designed. Then, the working principle of the switch was theoretically analyzed and modeled. Finally, by the combination of Computational Fluid Dynamics(CFD) simulation technology and a prototype experiment, the structure and functions of the switch were verified. The results show that fluid dispersion problem has been avoided even under the 30000g high step acceleration, and the bigger acceleration amplitude leads to the shorter response time. By the review of the experiment results, the height difference of the two liquid-gas interfaces of the brine can be realized at the initial state and the static acceleration threshold of the prototype is between 134.6g to 152.3g, which is agreed well with its theoretical counting acceleration threshold 142.7g. The experiments indicate that the micro communicating vessels efficiently improve the anti-dispersion ability of the microfluidic inertial switch. It separates the acceleration amplitude and shows good latching function and higher response characteristics to the high acceleration.