Eddy-current effects in an electromagnetic flowmeter

被引：13

作者：

Clarke, D. W. ^{[1
]}

Hemp, J. ^{[2
]}

机构：

[1] Univ Oxford, Dept Engn Sci, Oxford OX1 3PJ, England

[2] Univ Oxford Wolfson Coll, Oxford OX2 6UD, England

来源：

FLOW MEASUREMENT AND INSTRUMENTATION | 2009年 / 20卷 / 01期

关键词：

Electromagnetic flow-meter; AC excitation; Eddy currents; Magnetic modelling; SIGNAL; EXCITATION;

D O I：

10.1016/j.flowmeasinst.2008.09.002

中图分类号：

TH [机械、仪表工业];

学科分类号：

0802 ;

摘要：

A new two-dimensional analytical model is developed for the effect of eddy currents in the metal parts of an electromagnetic flowmeter under ac excitation. This model considers the influence of both the inner stainless-steel meter tube and the outer iron magnet core, treating them as thin sheets. Appropriate boundary conditions are derived across these sheets. The model predicts the coil impedance Z and the magnetic field B as complex numbers (magnitude and phase) for a given frequency f. The model is validated by extensive experiments on a commercial 2 inch meter using excitation frequencies in the range 10 Hz to 1 kHz. After first fitting some unknown physical parameters from the data, such as the effective core permeability g and the conductivity a of each metal component, the resulting model has a typical accuracy of better than 1% for the magnitude and phase of Z and B. (C) 2008 Elsevier Ltd. All rights reserved.

引用

页码：22 / 37

页数：16

共 23 条

[1]

Baker R.C., 2000, FLOW MEASUREMENT HDB

[2]

Bard Y, 1974, Nonlinear Parameter Estimation

[3] Eddy currents in thin plates modelled as surface regions [J].