双入口压电泵的流体混合仿真分析与验证

Simulation and experimental study on fluidic mixing of a dual-inlet piezoelectric pump

为简化微流体混合器的结构,在单腔体有阀压电泵的基础上,设计了一种新型的双入口压电泵。对双入口压电泵的结构及工作过程进行了分析,得出双入口压电泵可以实现两种流体的主动混合。为进一步研究双入口压电泵在进行流体混合时的混合形态,利用Fluent软件,对双入口压电泵工作过程中,泵腔内的流场形态进行模拟仿真,得出结论:双入口压电泵工作时,两个入口吸入的流体在泵腔内不发生混合,在出口单向阀处混合后输出。为验证仿真结果,对双入口压电泵进行流体混合试验测试,测试结果表明:双入口压电泵在工作时,泵腔内两种流体的交界面清晰,并不进行混合,在出口处混合后输出,与仿真结果一致。进一步测试了在不同驱动频率下,双入口压电泵的两入口吸入量占泵出量的百分比,得出结论:双入口压电泵的两入口吸入量占泵出量的百分比随着驱动频率的变化而发生变化,可以通过调节双入口压电泵的驱动频率来控制混合后流体的性质。

To simplify the structure of a microfluidic mixer, a novel dual-inlet piezoelectric pump was presented based on the previous studies concerning single-chamber piezoelectric pumps. Structural design and working princi-ple analysis were performed on the dual-inlet piezoelectric pump. It was observed that actively mixing two types of liquids was feasible for dual-inlet piezoelectric pumps. Furthermore, the simulation of the flow field when the pump was working was performed using the Fluent software. It was noticed that when the dual-inlet piezoelectric pump was working, the two types of fluids from the two inlets would mix behind the output check valve instead of in the pump chamber. This fluidic mixing in dual-inlet piezoelectric pumps was experimentally investigated to confirm the simu-lation results. The testing results showed when the dual-inlet piezoelectric pump was working, the boundaries of the two types of fluids were clear;the two types of fluids mixed behind the output check valve, validating the simulation results. Finally, the percentages of intake flow rates of the two inlets to output flow rates under different driving fre-quencies were tested. Deriving the fact that the percentages of intake flow rates of the two inlets to the output flow rates changed with the driving frequencies, the property of the output fluid can be controlled by altering the driving frequency of the dual-inlet piezoelectric pump.