夹心式压电超声换能器声场分析

Sound Field Analysis of Sandwich type Piezoelectric Ultrasonic Transducer

对谐振频率为28.4 kHz的夹心式压电超声换能器声场进行仿真分析,研究空化气泡对声场分布及噪声的影响。以COMSOL软件压力声学接口为基础,对换能器进行瞬态分析,观察有无空化气泡时空间内的声压分布情况,对比两种情况下截点位置的声压变化曲线及频域分布曲线。通过试验对仿真结果进行验证,确认空化气泡的存在增强了空间中的声场,使水中最大声压值由8×104 Pa增大至2.5×105 Pa,空气中最大声压值由80 Pa增大至140 Pa。水中的高声压区集中在空化区域内,空化区域后方的声压减弱。与此同时,空化气泡使空气中的低频噪声增加,截点位置的声压幅值由原来的2 Pa增大至4 Pa。

The acoustic field of a sandwich type piezoelectric ultrasonic transducer with a resonant frequency of 28.4 kHz was simulated and analyzed to study the influence of cavitation bubbles on the sound field distribution and noise.Based on the pressure acoustic interface in COMSOL software,a transient analysis for the transducer was performed to observe the distribution condition of sound pressure in the space with or without cavitation bubbles.The sound pressure curve and frequency domain distribution curve at the intercept point under two conditions were compared.The simulation results were verified by tests.It is confirmed that the existence of cavitation bubbles enhances the sound field in space,and the maximum sound pressure in water increases from 8×104 Pa to 2.5×105 Pa.The peak sound pressure in air increases from 80 Pa to 140 Pa.The high sound pressure zone in the water is concentrated in the cavitation zone,and the sound pressure behind the cavitation zone is weakened.At the same time,the cavitation bubbles increase the low frequency noise in the air,and the amplitude value of the sound pressure at the intercept point increases from the original value 2 Pa to 4 Pa.