基于高精度时差法的气体超声流量计研究  

Ultrasonic Gas Flowmeter Based on High Precision Time Difference Measurement

作　　者：潘旭东 赵伟国 章圣意[3] 林新霞 林恒 马也驰 PAN Xudong;ZHAO Weiguo;ZHANG Shengyi;LIN Xinxia;LIN Heng;MA Yechi(College of Metrological and Measurement Engineering,China Jiliang University,Hangzhou Zhejiang 310018,China;Zhejiang Key Laboratory of Flow Measurement Technology,China Jiliang University,Hangzhou Zhejiang 310018,China;Zhejiang Cangnan Instrument Group Co.,Ltd.,Cangnan Zhejiang 325800,China)

机构地区：[1]中国计量大学计量测试工程学院,浙江杭州310018 [2]中国计量大学浙江省流量计量技术研究重点实验室,浙江杭州310018 [3]浙江苍南仪表集团股份有限公司,浙江苍南325800

出　　处：《传感技术学报》2023年第3期490-496,共7页Chinese Journal of Sensors and Actuators

基　　金：国家市场监督管理总局科技计划项目(2019M146)。

摘　　要：针对气体超声流量计在测量中存在回波信号衰减大、波形易受工况影响的问题,提出了一种基于高精度时差的气体超声流量测量方法。该方法首先通过相似度评估回波信号,对回波信号特征点进行准确定位,进而获取飞行时间差的粗测量值,其次选取特定回波波形进行互相关法计算获得时差的细测量值,最后对两次测量结果相加得到高精度时差,从而实现高精度的流量测量。不同压力下的声速测量实验表明该方法在100 kPa至500 kPa范围内可准确测量飞行时间和时差。气体流量计样机的流量测量误差小于1%,重复性优于0.2%,并在大流量下与传统阈值法相比具有更高的准确性和更优的重复性。The echo attenuation is large and the waveform is easily affected by the working conditions of the ultrasonic gas flowmeter.In order to solve the problems,a gas ultrasonic flow measurement method is proposed based on high precision time difference.Firstly,the feature point of the echo signal is located according to the echo similarity and the coarse value of the time difference is calculated.Then the fine value of the time difference is calculated through cross-correlation of specific echo wave.Finally,the sum of the coarse value and the fine value is taken as the high accuracy time difference.Experiments of the sound velocity show that the proposed method can measure the flight time and the time difference from 100 kPa to 500 kPa precisely.The measurement error is less than 1%and the repeatability is lower than 0.2%in flow experiments.Especially in the large flow measurement,the flowmeter has higher precision and repeatability compared with the classic threshold approach.

关 键 词：气体超声流量计 回波相似度 特征点定位 互相关法 

分 类 号：TH814[机械工程—仪器科学与技术]