Effect of Magnetic Field Distribution on the Performance of the Electromagnetic Flow meter ia Partially- Filled Pipes

A. Ismael, Muneer; A. Rashack, Qais; Najem, S.E.

	Effect of Magnetic Field Distribution on the Performance of the Electromagnetic Flow meter ia Partially- Filled Pipes
Basrah Journal for Engineering Science
Article 1, Volume 9, Issue 1, 2009, Pages 25-33 PDF (0 K)
Authors
Muneer A. Ismael; Qais A. Rashack; S.E. Najem
Abstract
Electromagnetic flowmeters have proven their merit in measuring the flow rate of conducting liquids in fully-filled pipes. In contrast with the most of the published works about the electromagnetic flowmeter. the attentions were focused in this work into the use of these devices in partially-filled pipes. In this application these devices suffer from the problem of different outputs with different liquid level for the same flow rate. We studied whether the process of changing the distribution of the magnetic field through the measuring section improves the flowmeter performance against this drawback or not. An adaptive numerical mesh was used in predicting the flow induced signal and its response to the liquid level. The induced signal was assumed to be picked up by a pair of point electrodes tested for different angular positions. The results showed that the performance of the electromagnetic flowmeter in partially- filled pipes could be appreciably improved by making the magnetic field progressively decreases from top to the bottom of the flowmeter. When the lower magnet coil is excited by a current one- half lower than the upper coil together with two point electrodes placed at 22° below the flowmeter horizontal centerline, the fiowrneter performance offer more stable sensitivity.

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