压电致动微雾化器的压电-固-液耦合特性分析

Analysis of Piezoelectric-solid-liquid Coupling Characteristics of Micro Nebulizer

针对微雾化器存在的多能域能量耦合问题,建立了压电微雾化器的固-液-声耦合模型,对其耦合特性进行了数值计算,并着重分析了液体层厚度对耦合性的影响,得到了液体层厚度对系统的结构振动、声压力波特性的影响规律。结果表明,由于液体层与固体的耦合作用,压电振子振动的同时,喷孔膜也产生振动,并且两者间存在相位关系;液体层的厚度直接影响结构的耦合性、谐振频率大小及背膜与喷孔膜的相位差,并且存在最佳的设计参数,当液体层厚度为500μm时,谐振频率最大约是38kHz,此时,可产生较大的声压力波及较大的流量。微雾化器设计时只考虑压电振子的振幅是不全面的,必须同时考虑喷孔膜的振动及与背膜的相位关系,新的设计原则可为微雾化器的优化设计提供指导依据。

Aimed at the problem of multiple-domain coupling of piezoelectric micro nebulizer,a typical piezoelectric-solid-liquid coupling model was built up. A FEM model was presented for this piezoelectric liquid-structure coupling system,focusing on the thickness of liquid impact on the coupling of the system.The results showed that when the piezoelectric actuator was vibrated,because of the coupling of the liquid layer and solid,nozzle-film also was generated vibration at the same time,and the phase relationship occurred to them;the coupling,resonant frequency of the system and the phase difference between back film and nozzle film were affected greatly by the thickness of liquid;and existing the best design parameters,when the thickness of liquid layer was 500 μm.The resonant frequency of the largest was about 38 kHz,which could have a greater sound pressure wave,as well as the larger flow rate.Therefore,it was incomprehensive only to consider the amplitude of piezoelectric vibration,we must also consider the nozzle film vibration,as well as the phase between back film and the nozzle film,and this can provide guidance for the optimal design of micro nebulizer.