聚焦式低频超声雾化喷头的设计及仿真

Design and Simulation of Focusing Low-frequency Ultrasonic Atomizing Nozzle

通过建立喷头理想数学模型的连续体纵向振动微分方程并求解,确定了喷头的结构尺寸;应用ANSYS软件建立了喷头的有限元模型,求解了该喷头在20～35kHz之间的固有频率和相应振型,通过尺寸调整和模态分析,确定了其纯拉压振型的固有频率为27 977Hz,而PV 70A检测喷头的实际拉压固有频率为28 319Hz,结果仅相差1.22%;为确定加载在换能器压电陶瓷上的电压对低频超声雾化喷头瞬态动力学特性的影响,建立了喷头的力电耦合有限单元模型,比较了喷头压电陶瓷在不同波形(正弦波电压、三角波电压和矩形波电压)以及不同大小(20,40,60,80,120,140,160V)的电压驱动下,喷头雾化面的瞬态响应规律。研究结果表明,正弦波和三角波电压激励的响应远小于矩形波,相对于正弦波和三角波电压,矩形波激励较为合理,其端面响应随激励电压的增大而增大,所设计喷头的结构满足要求。

The structure of the shower nozzle size was determined by solving the nozzle continuum longitudinal vibration differential equation. The finite element model （FEM） of the shower nozzle was constructed by software ANSYS and solved from 20kHz to 35kHz between the inherent frequency and corresponding vibration model to get its pure tension compression vibration mode. According this FEM calculating result, the nozzle＇ s pure tension compression vibration mode natural frequency was 27977 Hz while the actual frequency measured by PV 70 A was 28319Hz. The calculating error was less than 1.22%. Electrical and force coupling finite element model of this nozzle was established to compare with the transient response of the law of the piezoelectric ceramic nozzle in different waveform （sine wave voltage, triangle wave voltage and rectangular wave voltage） and different voltage （20 , 40, 60, 80, 120,140 and 160V） voltage drive. It＇ s showed that, compared with the sine wave voltage and triangle, rectangle wave was most suitable to drive this nozzle. The displacement of atomizing surface was directly proportional to the nozzle＇ s drive voltage.