LIAO Cui-lin, LU Li, WANG Wan-peng, MA Su-ping

Beijing IWHR Technology Co., IWHR, Beijing 100038, China

Abstract: The electromagnetic flowmeter is a widely used flow measurement instrument, and the length of measured straight pipe plays a key role in ensuring both the axisymmetrical velocity distribution of the flow in the pipe and the measurement accuracy of electromagnetic flowmeter. In this paper, the length of measured straight pipe and the axisymmetrical properties of velocity distribution in the pipe are studied based on CFD numerical method. In order to study the axisymmetrical degree of velocity distribution in the measurement pipe accurately and quantitatively, a new method, symmetric deviation degree, is presented. With this method, the axisymmetrical properties of velocity distribution of the flow in the pipes with different diameters and flowrates are studied, and also the required lengths of the electromagnetic flowmeter on the measured straight pipes are calculated. The conclusions provide scientific theory for the verification, installation and application of electromagnetic flowmeter as well as foundation for the supporting project to establish high-precision flow measurement standard equipment.

Key words: electromagnetic flowmeter; velocity; symmetric deviation degree; the length of measured straight pipe; CFD

Published in: Journal of China Institute of Water Resources and Hydropower Research (Vol. 11 No. 3, 2013)