通道型电磁常闭微阀结构参数优化

Optimization of structure parameters of channel-type electromagnetic microvalves

优化了通道型电磁常闭微阀的结构参数,以提高其工作性能。基于近似结构模型对结构参数进行理论分析;以泄漏率为指标,利用有限元方法仿真分析了微通道的宽度、高度,底膜厚度,顶膜厚度及电磁驱动机构压力等主要结构参数对泄漏率的影响。提取了经验公式,基于正交实验法研究了结构参数对泄漏率和开启率的影响。最后,结合理论分析、仿真和正交实验结果对微阀结构参数进行了优化。实验结果表明,通道高度和宽度对泄漏率影响最大,通道高度对开启率影响最大。获得最优开闭性能的结构参数组合为:通道宽度1 mm,高度0.1 mm,底膜厚度0.2 mm,顶膜厚度0.2mm,电磁机构压力3×104 Pa。基于该结构参数组合的微阀在10kPa内可以实现零泄漏及近似完全开启。该阀具有易与微流控芯片集成、低电压驱动、制作简单、无死体积等优点。

The structure parameters of a channel-type electromagnetic normally-closed microvalve were optimized to improve its performance.Firstly,the structure parameters were analyzed theoretically based on an approximate structure model.The impacts of main structure parameters on the leakage rate,such as the width and height of a microchannel,the thicknesses of bottom and top films,and the pressure generated by a electromagnetic mechanism were analyzed based on the Finite Element Simulation（FES）,and then a empirical formula was established.On the orthogonal experiment method,the influences of the structure parameters on the leakage rate and the open rate were also researched.Finally,the structure parameters of the microvalve were optimized according to the theoretical analysis,FES and the experiment results.The experimental results show that the width and height of the microchannel have the effect on the leakage rate greatly,and the channel height effects on the open rate most.Furthermore,the optimal structure parameters of the microvalve are the width and height to be 1 mm and 0.1 mm,the bottom and top film thicknesses both to be 0.2 mm,and the pressure to be 3 × 104 Pa,respectively.On the parameters mentioned above,the microvalve has no detectable leakage flow when the backpressure is up to 10 kPa.The microvalve shows its advantages on the low-voltage driving,zero dead volume,simple process and easy to integrate with microfluidic devices.