Department of Thermal Science, Faculty of Mechanical and Power Engineering, Wrocław University of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wrocław, Poland.
Polytechnic Faculty, Calisia University, 62-800 Kalisz, Poland.
Sensors (Basel). 2023 May 11;23(10):4677. doi: 10.3390/s23104677.
The aim of this work is to experimentally determine and evaluate the value of the correction factor for ultrasonic flow meters in order to improve their accuracy. This article concerns flow velocity measurement with the use of an ultrasonic flow meter in the area of disturbed flow behind the distorting element. Clamp-on ultrasonic flow meters are popular among measurement technologies due to their high accuracy and easy, non-invasive installation, because the sensors are mounted directly on the outer surface of the pipe. In industrial applications, installation space is usually limited and, therefore, flow meters frequently have to be mounted directly behind flow disturbances. In such cases, it is necessary to determine the value of the correction factor. The disturbing element was a knife gate valve, a valve often used in flow installations. Water flow velocity tests were performed using an ultrasonic flow meter with clamp-on sensors on the pipeline. The research was performed in 2 series of measurements with different Reynolds numbers of 35,000 and 70,000, which correspond to a velocity of approximately 0.9 m/s and 1.8 m/s. The tests were carried out at different distances from the source of interference, within the range of 3-15 DN (pipe nominal diameter). The position of the sensors at successive measurement points on the circuit of the pipeline was changed by 30 degrees. Flow velocity measurements were carried out for two different levels of the valve's closure: 1/3 and 1/2 of the valve's height. For the collected velocity values at single measurement points, the values of the correction coefficient, K, were determined. The results of the tests and calculations prove that compensation error of measurement performed behind the disturbance without keeping the required straight sections of the pipeline is possible by using the factor K*. The analysis of the results made it possible to identify the optimal measuring point at a distance from the knife gate valve as being smaller than specified in the standards and recommendations.
本工作旨在通过实验确定和评估超声流量计的修正系数值，以提高其精度。本文涉及在扭曲元件后的扰流区使用超声流量计测量流速。由于其高精度和易于安装、非侵入式的特点，夹式超声流量计在测量技术中很受欢迎，因为传感器直接安装在管道的外表面上。在工业应用中，安装空间通常有限，因此流量计经常需要直接安装在流量干扰之后。在这种情况下，必须确定修正系数的值。干扰元件是刀形闸阀，是流量装置中常用的一种阀。使用夹式传感器的超声流量计在管道上进行水流速度测试。研究在两个不同雷诺数的测量系列中进行，雷诺数分别为 35000 和 70000，对应流速约为 0.9 米/秒和 1.8 米/秒。测试在不同的干扰源距离范围内进行，距离范围为 3-15 DN（管道公称直径）。在管道回路的连续测量点上，通过 30 度改变传感器的位置。在阀门关闭的两个不同高度（阀门高度的 1/3 和 1/2）下，对两个不同的传感器位置进行了流速测量。对于单个测量点采集到的流速值，确定了修正系数 K 的值。测试和计算结果表明，在不保持所需的直管道段的情况下，在干扰后进行测量的补偿误差是可能的，通过使用系数 K*。对结果的分析使得可以确定距离刀形闸阀的最佳测量点，其距离小于标准和建议中规定的距离。
