Electromagnetic flowmeter evaluation in real facilities: Velocity profiles and error analysis

The reliability and accuracy of a flowmeter depends on its installation conditions, as an improper installation may distort the end results. The objective of this work was to determine the errors obtained in an electromagnetic flowmeter of 100 mm diameter, installed in common real conditions, that is, not obeying the straight pipelines length recommended in flowmeter standards. To achieve this objective of the work, the electromagnetic flowmeter was installed in four different conditions: installed downstream of a 90 degrees curve and down-stream of two curves of 90 degrees, both of short radius; downstream of a gate valve, openings of 100% and 50%. During the research, flow velocity profiles were obtained, with the purpose of evaluating the influence of profile distortion on the performance of the meter. The tests were carried out in the Laboratory of Hydraulics and Fluid Mechanics of FEC-Unicamp, Brazil, and the results are consubstantiated in comparative graphs, which demonstrate the influence of the velocity profile on the flowmeter response and accuracy for each setup bench.