两级缓冲式光声池仿真设计及性能分析  

Simulation Design and Performance Analysis of Two-Stage Buffer Photoacoustic Cell

作　　者：靳华伟[1,2,3] 王浩伟 罗平 方磊 JIN Hua-wei;WANG Hao-wei;LUO Ping;FANG Lei(School of Mechanical Engineering,Anhui University of Science and Technology,Huainan 232001,China;Institute of Environment-friendly Materials and Occupational Health of Anhui University of Science and Technology(Wuhu),Wuhu 241003,China;Key Laboratory of Environmental Optics&Technology,Anhui Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Hefei 230031,China)

机构地区：[1]安徽理工大学机械工程学院,安徽淮南232001 [2]安徽理工大学环境友好材料与职业健康研究院(芜湖),安徽芜湖241003 [3]中国科学院安徽光学精密机械研究所环境光学与技术重点实验室,安徽合肥230031

出　　处：《光谱学与光谱分析》2023年第8期2375-2380,共6页Spectroscopy and Spectral Analysis

基　　金：安徽省高校自然科学研究重大项目(KJ2021ZD0052);安徽理工大学环境友好材料与职业健康研究院研发专项基金项目(ALW2020YF17)资助。

摘　　要：光声池是发生“光-热-声”耦合的场所,光声池性能的优劣直接影响检测系统的精度与灵敏度。为了提高光声池的性能,在传统圆柱形光声池的基础上,提出了一种两级缓冲式光声池。利用COMSOL软件中热粘性声学物理场接口仿真分析了缓冲隔板高度及缓冲隔板数量对光声池内声场的影响规律。结果表明,光声池的共振频率随缓冲隔板数量和高度的增大而减小。当缓冲隔板的数量固定,缓冲隔板高度H大于11 mm时,光声池的共振频率随缓冲隔板高度的增加而急剧减小。在光声池共振频率要求范围内,共振频率的减小有利于光声信号幅值的提高;当缓冲隔板的高度固定时,光声池的声压随缓冲隔板数量的增加而减小;当缓冲隔板高度在0~11 mm之间时,声压值保持相对稳定;当缓冲隔板高度大于11 mm时,声压值随缓冲隔板高度的增加而急剧减小。流场方面,通过在缓冲腔内设置缓冲隔板可减小左侧缓冲腔内的速度梯度。一级缓冲方式虽可一定程度减小速度梯度,但在缓冲隔板处出现速度波动,而两级缓冲方式不仅减小了光声池内的速度梯度,而且使气体流速更加平稳。考虑到光声信号幅值、声压及光声池内速度梯度等指标,选用缓冲隔板高度为11 mm,缓冲隔板数量为2。基于所给最优参数的两级缓冲式光声池,仿真及实验结果表明:所设计的两级缓冲式光声池和同尺寸的圆柱形光声池相比,声压由3.34×10^(-5)降低为3.32×10^(-5),本底噪声由(2.83±0.11)μV降低为(1.26±0.03)μV,共振频率由1344 Hz降低为1299 Hz。虽声压减小了1.2%,但声噪比提高了2.22倍,且共振频率在满足要求的范围内降低了3.3%,使光声信号幅值得到一定程度提升。整体来说,两级缓冲式光声池稳定了气体流动噪声,减小了流动噪声的波动幅度,为光声池优化设计提供了一种新的思路。The photoacoustic cell is where the“light heat sound”coupling occurs.The performance of photoacoustic cells directly affects the accuracy and sensitivity of the detection system.In order to improve the performance of photoacoustic cells,a two-stage buffer photoacoustic cell is proposed based on the traditional cylindrical photoacoustic cell.Through the simulation of the thermal viscous acoustic physical field interface in COMSOL software,the effects of the height and number of buffer partitions on the sound field in the photoacoustic cell are analyzed.The results show that the resonance frequency of the photoacoustic cell decreases with the increase in the number and height of buffer partitions.When the number of buffer partitions is fixed,the height of the buffer partition is greater than 11mm,and the resonance frequency of the photoacoustic cell decreases sharply with the increase of the height of the buffer partition.In the required range of photoacoustic cell resonance frequency,the decrease of the resonance frequency is conducive to the increase of photoacoustic signal amplitude;When the height of the buffer partition is fixed,the sound pressure of the photoacoustic cell decreases with the increase of the number of buffer partition;When the height of the buffer partition is between 0 and 11mm,the sound pressure value remains relatively stable;When the height of the buffer partition is greater than 11mm,the sound pressure decreases sharply with the increase of the height of the buffer partition.Regarding flow field,the velocity gradient in the left buffer cavity can be reduced by setting a buffer partition in the cavity.Although the one-stage buffer can reduce the velocity gradient to a certain extent,there is velocity fluctuation at the buffer partition.The two-stage buffer reduces the velocity gradient in the photoacoustic cell and makes the gas flow more stable.Considering the photoacoustic signal amplitude,sound pressure and velocity gradient in the photoacoustic cell,the height of the buffer partitio

关 键 词：光声光谱 光声池 有限元分析 优化设计 

分 类 号：O433.1[机械工程—光学工程]