成像最小声压级校准及不确定度评定  

Calibration of Minimum Imaging Sound Pressure Level in Air Ultrasonic Source Imagers and Uncertainty Assessment

作　　者：张瑞纹 庞晓峰 高申平 沈煜航 ZHANG Ruiwen;PANG Xiaofeng;GAO Shenping;SHEN Yuhang(Shenzhen Institute of Metrology and Quality Inspection,Shenzhen 518072,China;Zhejiang Institute of Metrology,Hangzhou 310018,China;China Jiliang University,Hangzhou 310018,China)

机构地区：[1]深圳市计量质量检测研究院,深圳518072 [2]浙江省计量科学研究院,杭州310018 [3]中国计量大学,杭州310018

出　　处：《计量科学与技术》2023年第11期71-78,共8页Metrology Science and Technology

基　　金：浙江省市场监督管理局科技项目(QN2023421)。

摘　　要：空气超声源成像仪(波束形成法)广泛应用于局部放电及气体泄漏检测中,其成像最小声压级的校准是空气超声源成像仪定量技术的前提,直接影响空气超声源成像仪可检出的最小气体泄漏量、工作距离及局部放电的检出能力。随着波束形成技术的不断发展,通过优化阵列尺寸、传声器数目、传声器间隔等参数,声源识别定位的精度不断提高,在传声器阵列便携的前提下,可识别的成像最小声压级不断减小,使该参数的定量结果不易得到,为国内外产品在参数比对和定量测量造成困扰。基于低本底噪声测量系统,搭建空气超声源成像仪成像最小声压级校准系统,选择三款使用广泛的空气超声源成像仪进行实验,选择小尺寸声源模拟局部放电和气体泄漏引起的声学信号,确定校准距离与校准环境,通过同心定位圆环组监测小尺寸声源的成像定位误差,辅以12线高精度激光水平仪减小信号对齐带来的影响,实现对成像最小声压级进行校准。对测量结果进行不确定度评定,结果表明,在20~40 kHz频率范围内,成像最小声压级的扩展不确定度可以达到3 dB(k=2)。The air ultrasonic source imager(beamforming method)is widely utilized in detecting partial discharges and gas leaks.Calibration of its minimum imaging sound pressure level(SPL)is crucial for quantitatively assessing the instrument,directly impacting the detection capabilities for minimal gas leaks,operating distance,and partial discharge detection.With beamforming technology advancements,optimizing array size,number of transducers,and inter-transducer spacing has enhanced source identification and positioning accuracy.As a result,under portable array conditions,the detectable minimum imaging SPL has decreased,posing challenges in obtaining quantitative results,and causing comparison and measurement issues in domestic and international products.This study establishes a calibration system for the minimum imaging SPL of air ultrasonic source imagers using a low-background noise measurement system.Three widely-used air ultrasonic source imagers are selected for experiments,simulating acoustic signals from partial discharges and gas leaks with small-sized sources.Calibration distance and environment are determined,and concentric positioning rings are used to monitor imaging localization errors of small sources.A 12-line high-precision laser leveler aids in minimizing signal alignment impact.This method enables the calibration of minimum imaging SPL.The measurement uncertainty is assessed,showing that within the 20–40 kHz frequency range,the expanded uncertainty of the minimum imaging SPL can reach 3 dB(k=2).

关 键 词：计量学 成像最小声压级 空气超声源成像仪 波束形成 不确定度评定 

分 类 号：TB95[一般工业技术—计量学]