Study of Effect of Straight Pipe Length on Ultrasonic Flowmeter Measurement during Typical Baffle Interference

Abstract

: On the current domestic market, a variety of ultrasonic flowmeters, including those with four (sound) channels, six channels, and eight channels, either through-beam and retro-reflective in channel arrangement, are all claimed to be extremely adaptable to baffle interference and have shorter straight pipes than required by the national standard. To observe and study the tolerance of these gas ultrasonic flowmeters to typical baffle interference and the requirements on the length of the front straight pipe segment, our technical team, according to the process installation requirements of GB/T18604-2014 measurement of natural gas flow by gas ultrasonic flow meters, as well as the AGA NO.9 -2017 report, use the turbine working standard combination system as a flow measurement standard device to test the real flow of natural gas for representative DN100 gas ultrasonic flowmeters with A, B, C, and D channels and different arrangements. Testing process: First, basic data were obtained by testing under ideal pipeline conditions, and then a flow regulator is installed under the interference conditions of typical flow blocking parts (space elbow and manifold are located 30D, 20D and 15D upstream of ultrasonic flowmeter), and see whether the main technical indicators can meet the requirements of trade handover. The technical team of the author designed the test of the effect of different process installation conditions on the measurement accuracy of the gas ultrasonic flowmeter and put forward their own views on the basis of analyzing the test data.