Uniform magnetic flux density simulation and verification for a new electromagnetic flow meter

Abstract

The measurement of the distribution of magnetic flux density in an electromagnetic (EM) flow meter is important in obtaining an accurate flow rate. In this paper, Helmholtz coils are used in the EM flow meter to generate a homogenous magnetic flux density across the cross section of flow pipe. The finite element method analysis software, COMSOL, was used to build a model of the magnetic flux density, which was then verified using experimental testing. A 2D magnetic camera system containing an 8 × 8 array of 64 Hall sensors is used to detect the magnetic flux density. The magnetic flux density data is then measured using a national instruments PCI 6255 data acquisition card. The results from the simulation model and experimental measurements are presented and compared in the paper. The study is useful in designing the electrode sensor arrays of an EM flow meter. In addition to this, the distribution of magnetic flux density is useful in improving the accurate flow rate measurement of the EM flow meter.

Keywords:

• Helmholtz coil
• electromagnetic flow meter
• magnetic flux density
• magnetic camera
• Hall sensor

Acknowledgements

The authors would like to acknowledge the financial support of EPSRC (Grant no. EP/E013031/1). The authors also thank Professor Jinyi Lee from Korea developed the magnetic camera funded from the Royal Society in Newcastle.