针对仿鱼类侧线的敏感单元提出了一种新型的封装,即采用与透声帽相同材料的聚氨酯代替蓖麻油进行灌封,且聚氨酯仅淹没到纤毛的一半,该封装结构能够提高矢量水听器的灵敏度。建立了水听器封装结构的声学理论模型,并由此推导出新型封装结构的透声系数。采用ANSYS对矢量水听器敏感单元封装结构进行仿真,得出传感器的灵敏度为0.259 mV/Pa,共振频率为150 Hz。测试具有此封装结构的水听器样机,结果表明:该样机的声压灵敏度达到-188.9 dB,比蓖麻油封装结构的灵敏度(-197.7 dB)提高了8.8 dB;具有典型的"8"字型指向性的特征;工作频段为50 Hz~2 kHz。
A novel encapsulation structure was proposed to package the sensitive unit,which imitated the fish lateral line cells.That was,polyurethane the same material as sound-transparent cap,instead of castor oil,was selected to encapsulate.And only half of the hair was submerged.It is desirable that the novel encapsulation can effectively improve vector hydrophone ' s sensitivity.By means of analysis vector hydrophone ' s theoretical model,the acoustical transmission coefficient was obtained.This paper simulated the encapsulation model by ANSYS and it could be concluded that the sensitivity was 0.259 mV/Pa,resonance frequency was 150 Hz.Finally,the prototype of the vector hydrophone was fabricated and tested.Results show that the free-field voltage sensitivity is-188.9 dB,which is 8.8dB higher than that of castor oil encapsulation.The hydrophone possesses satisfactory directional pattern and frequency response ranges from 50 Hz to 2 kHz.