液体超声流量测量中的传播时间精度分析

Study of the accuracy of transit time ultrasonic flow measurement for liquids

液体超声流量高精度测量中使用传播时间法需要精确测量绝对传播时间和相对传播时间,针对绝对传播时间的基波信号不易得到的情况,提出了一种基波信号提取方法,通过设定能量和相位约束边界保证提取基波信号的准确性,划分流速分布区间根据实际测量流速自适应调整基波信号;通过仿真对影响相对传播时间精度的采样率、峰值搜索因素进行了深入分析;设计实验系统并在液压平台上对提出的方法和仿真分析进行验证,结果证明了基波信号提取方法的有效性和仿真分析的正确性。

High-precision measurement of liquid flow using transit time method requires accurate measurements of the absolute propagation time and the relative propagation time.The reference signal for the measurement of the absolute propagation time in ultrasonic flow measurement is rather difficult to get.Aiming at this problem,an extraction method of the reference signal is presented.The boundary conditions for energy and phase are set to ensure the accuracy of the extracted reference signal,which can adaptively adjust the fundamental signals according to the actual velocity distribution interval.The sampling rate and peak detector factors that influence the precision of the relative time difference are further studied with simulation analysis;An experimental system is designed and the proposed method and the simulation analysis are verified on a hydraulic platform.The results prove the effectiveness of the method and the correctness of the simulation analysis.