基于互相关的堆积物料中声波传播时间测量  

Measurement of sound travel time in stored bulk material using cross-correlation techniques

作　　者：郭淼[1] 胡永辉 闫勇[1,2] 卢钢[2] Guo Miao;Hu Yonghui;Yan Yong;Lu Gang(School of Control and Computer Engineering,North China Electric Power University,Beijing 102206,China;School of Engineering and Digital Arts,University of Kent,Canterbury,CT2 7NT,UK)

机构地区：[1]华北电力大学控制与计算机工程学院,北京102206 [2]英国肯特大学工程与数字艺术学院

出　　处：《电子测量与仪器学报》2018年第12期1-9,共9页Journal of Electronic Measurement and Instrumentation

基　　金：中央高校基本科研业务费专项(2015XS64);留学基金委(201506730012);华北电力大学"双一流"研究生人才培养项目资助

摘　　要：堆积物料如生物质燃料内部的温度需要进行连续监测,来防止其储存时的自燃现象。声学技术可以非侵入式地测量堆积物料内部的温度。通过测量低频声波在堆积物料间隙内的声速可以计算出间隙中空气的温度,即周围物料的温度。为了测量声波在堆积物料中的声速,首先需要测量声波的传播时间。互相关法是基于传感器接收声波的波形相似性来预测时延,可以克服反射声波对时延估计的影响,因此选择互相关法来测量声波传播时间。为了研究声源信号对传播时间测量的影响,比较了4种常见的声源信号,包括扫频、白噪声、最大长度序列信号和指数衰减正弦波脉冲信号,同时研究了扫频信号的类型、频带和长度的选择。实验结果表明,使用长度为0.1 s、频带在200～500 Hz的线性扫频信号作为声源信号,结合互相关技术可以实现对声波在堆积物料内传播时间的有效测量。The temperature of stored bulk material should be monitored continuously to suppress the potential internal self-ignition. Acoustic techniques can be used to measure the temperature of stored bulk material non-intrusively. By measuring the speed of lowfrequency sound waves,the temperature of the air in the gaps of stored bulk material is determined,which is assumed to be the same as the temperature of the surrounding material. To measure the sound speed in stored bulk material,the traveling time of sound needs to be measured. The principle of cross-correlation method is based on the similarity between the sound signals received by the acoustic sensors. Since the cross-correlation method can overcome the influence of reflected sound waves on time delay estimation,it is adopted in this study. A suitable excitation source signal should be selected to use the cross-correlation method. Four types of source signal ( chirp signal,white noise,maximum length sequence signal and exponentially decaying sinusoidal pulse) are compared. Moreover,the type, the frequency band and the length of the chirp signal are also investigated comparatively. Experimental results show that the crosscorrelation method using a 0. 1 s linear chirp sound signal in the frequency band of 200 ~ 500 Hz as the source signal is suitable for the measurement of the traveling time of sound in stored bulk material.

关 键 词：温度测量 声波传播时间 互相关 扫频 

分 类 号：O422[理学—声学]