超声消除电缆火灾烟雾的实验研究

Experimental study of ultrasonic elimination of cable fire smoke

声波团聚技术是利用高强声场的作用使颗粒物发生相对运动从而碰撞并凝聚,大幅减少悬浮的颗粒物。当今城市地下电缆一旦发生火灾将造成巨大的生命及财产损失。在火场应用声波团聚技术能够大幅提高火场的能见度,有助于人员逃生。文章研究了超声场下消除地下电缆火灾烟雾的效果。首先设计了一款频率为18 kHz的气介式换能器,并对其进行模态分析;随后加工了声源,测试其发声效果。结果表明,换能器在开放空间及团聚室内声压级最高分别可达154.1 dB及158.7 dB。开放空间下输入功率越高、越靠近圆盘中心,声压级越高;团聚室内中间监测点处由于壁面及底部反射作用声压级最高。团聚实验结果表明,在声压级为155 dB、初始透光率为8%时,对于液相烟雾及电缆烟雾,分别在5、15 s内透光率达到60%,这表明在超声场下,团聚效果显著,且团聚效果随声压级的增大而增大。

Acoustic agglomeration technology uses high-intensity acoustic field to make aerosol particles collide and condense rapidly,thereby,the mass concentration of particles is greatly reduced.Nowadays,once the underground cable fires,it will cause huge loss of life and property.The application of acoustic agglomeration technology can greatly improve the visibility of the fire scene and help people escape.In this paper,the experimental study of using the ultrasonic field to eliminate the smoke of the underground cable fire is studied.Firstly,an ultrasonic transducer of 18 kHz is designed and its modal analysis is carried out.Then,a sound source prototype is made.The sound source test results show that the high-intensity ultrasonic transducer can emit the sound wave with a sound pressure level(SPL)up to 154.1 dB and 158.7 dB in the open space and in the agglomeration room,respectively.In open space,the higher the input power and the closer to the center of the disk,the higher the sound pressure level.The SPL at the middle monitoring point of the agglomeration room is the highest due to the reflection of the wall and bottom.The results of the agglomeration experiment show that when the SPL is 155 dB and the initial light transmittance is 8%,for liquidphase smoke and cable smoke,the light transmittance reaches 60%within 5 s and 15 s,respectively,which indicates that the agglomeration effect is significant under ultrasonic field and the agglomeration effect increases with the increase of the SPL.