一种电容式声压水听器的热粘性声学仿真研究

为了满足多领域中水下复杂环境声压检测的需要,提出了一种基于微机电系统(MEMS)的电容式声压水听器,开发出注油孔及注油沟道设计,将传感器封装于硅油中,通过平衡振动薄膜内外压强可以提高其耐受静水压能力。使用Comsol Multiphysics仿真软件对水听器建模,采取热粘性声-结构多物理场对传感器进行静态分析、模态分析及谐波声信号扰动下的灵敏度分析,在用有限元法分析模型时考虑了热效应与粘滞效应对小尺寸声学换能器的影响,使仿真结果更具说服力。得到了在幅值为10 Pa,频率在1 Hz～10 kHz的谐波声信号扰动下水听器的接收灵敏度为-147 dB。仿真结果表明,设计的电容式声压水听器据有高灵敏度和宽频带等特点,可以满足不同领域对水下低频声压信号的测量需求。

Thermo Viscous Acoustic Simulation of a Capacitive Acoustic Pressure Hydrophone

In order to meet the needs of sound pressure detection in complex underwater environment in many fields, a capacitive sound pressure hydrophone based on MEMS is proposed. The design of oil injection hole and oil injection channel is developed. The sensor is encapsulated in silicon oil. By balancing the internal and external pressure of vibration film, its ability of withstanding static water pressure can be improved. The hydrophone was modeled through Comsol Multiphysics simulation software, and the static analysis, modal analysis and sensitivity analysis under harmonic acoustic signal disturbance were carried out by utilizing the thermos viscous acoustic structure multi physics field. The influences of thermal effect and viscous effect on small size acoustic transducer are considered in finite element analysis, which makes the simulation results more convincing. The receiving sensitivity of the hydrophone is -147 dB under the disturbance of the harmonic acoustic signal with the amplitude of 10 Pa and frequency of 1 Hz~10 kHz. The simulation results show that the designed capacitive acoustic pressure hydrophone has the characteristics of high sensitivity and wide band, which could meet the measurement requirements of underwater low frequency acoustic pressure signals in different fields.