差分式小流量科氏流量计相位差估计实验分析

Experimental analysis of phase difference estimation for differential micro flow Coriolis flowmeter

相位差估计算法对科氏流量计精度有直接影响,在小流量测量时对算法要求更高。为分析不同相位差估计算法在小流量检测中的性能,针对一种差分式小流量科氏流量计,开展实验研究和对比分析。阐述了差分式小流量科氏流量计计量原理,分析了滑动Goertzel算法、负频率修正DTFT算法和ap-Hilbert法,在1 g/min~50 g/min流量范围内开展水流量测试实验,并对比分析3种算法的相位差估计结果、质量流量测量结果。实验结果表明,3种算法均能够较准确地估计质量流量且稳定性较好;ap-Hilbert与负频率修正DTFT算法的精度相近,较滑动Goertzel算法精度更高,3种算法相对误差均小于1%(流量>15 g/min),可满足实际应用的精度要求。

The phase difference estimation method has a direct impact on the measurement accuracy of Coriolis flowmeter.In the measurement of micro flow,higher requirements are put forward for methods.In order to analyze the performance of different phase difference estimation methods in micro flow measurement,experimental research and comparative analysis are carried out for a differential micro flow Coriolis flowmeter.The measurement principle of differential micro flow Coriolis flowmeter is described,the sliding Goertzel,negative frequency modified DTFT and ap-Hilbert method is analyzed,water flow measurement experiments in the flow range of 1 g/min-50 g/min is carried out,and the phase difference estimation results and mass flow measurement results of the three methods.The experimental results show that the three methods can accurately estimate the mass flow and have good stability are compared;the accuracy of ap-Hilbert and negative frequency modified DTFT is similar,higher than that of sliding Goertzel.The relative errors of the three methods are less than 1%(flow>15 g/min),which can meet the accuracy requirements of practical application.