微气泡执行器强化微混合的实验研究

微尺度流动的雷诺数(Re)比较低,其混合主要通过扩散来完成,因此需要较长的距离与时间才能混合均匀。为实现微尺度低Re数流体的快速均匀混合,以甲醇及染色甲醇为工质,采用脉冲电压激励微铂膜产生可控气泡,并以气泡周期性胀缩产生的脉冲压力为动力源,研究脉冲压力横向扰动产生的混沌流对微通道内流动混合的影响。结果表明:脉冲压力横向作用使流体的交界面产生了强烈的卷曲拉伸,有效地强化了混合,该微混合器能够在毫米级混合长度及毫秒级混合时间内快速均匀混合,脉冲频率越高,混合效果越好。本研究结果为解决微尺度下低Re数流动混合难题提供了一种有效的崭新手段。

Experiment Investigation of Enhancement Micromixing by Microbubble Actuators

Mixing in microscale at the low Reynolds number needs much longer mixing distance and time to achieve uniform mixture because it only depends on the diffusion effect.To enhance the fluid mixing in microfluidic system at low Reynolds number quickly and effectively,methanol and methanol with black dye used as working fluids,the microbubble was generated by the pulse voltage loaded on the platinum film and the microbubble on the platinum film brought about periodic expansion and shrinkage thereby generated a pulse pressure.The effect of the chaotic advection mixture performance generated by the lateral disturbance on the fluid mixing in microchannel was discussed.The experiment results indicate that the pulse pressure lateral distur-bance makes the interface of the two fluids induce folding and stretching strongly,which enhances the fluids mixing in the microchannel effectively.The micromixer based on the pulse drive can achieve effective mixing performance in the millimeter mixing length and in the millise-cond time.Furthermore,the higher the pulse frequency loaded on the platinum heating film is,the better the mi-xing performance is.The results provide a new and effective method to solve the mixing problem in microscale at the low Reynolds number.