烟气超声流量计时间测量准确度校准方法研究

Study on calibration method of time measurement accuracy of flue gas ultrasonic flowmeter

大口径气体超声波流量计广泛应用于烟道排放监测和工业控制等领域。超声波流量计的传播时间测量准确度校准是非实流校准的重要环节,通过建立超声波流量计时间测量准确度校准装置,实现对大口径气体超声流量计传播时间的非实流校准。该文首先提出3种不同的超声流量计传播时间校准方法,分析不同方法的影响因素,其次通过改变探头间距离,对不同探头间距时超声波流量计传播时间的测量误差进行校准。试验结果表明:超声波流量计传播时间的测量误差随距离变化,并确定利用标准声速对超声波流量计传播时间进行修正的方法更为准确,测量结果不确定度为0.2%。

Large diameter gas ultrasonic flowmeter is widely used in stack emission monitoring and industrial control.The accuracy of the propagation time measurement of the ultrasonic flowmeter is an important part of dry calibration.Through the establishment of the ultrasonic flowmeter time measurement accuracy calibration facility,it can realize the dry calibration of the propagation time of large diameter gas ultrasonic flowmeter.This paper firstly proposes three different methods of ultrasonic flowmeter propagation time calibration,and analyzes the influencing factors of different methods,and then calibrates the measurement error of ultrasonic flowmeter propagation time when different probe spacing is changed.The test results show that the measurement error of ultrasonic flowmeter propagation time varies with distance,and it is more accurate to determine the propagation time of the ultrasonic flowmeter using the standard sound velocity.The uncertainty of the measurement result is 0.2%.