A Numerical Approach to Determine the Magnetic Field Distribution of an Electromagnetic Flow Meter

This paper addresses the design of a novel electromagnetic flow meter for use in multiphase flows. The relationship between the magnetic field distribution, the induced electrical potential and the velocity distribution of the conducting continuous phase was studied using COMSOL Multiphysics software (formally known as FEMLAB). The electromagnetic flow meter was modelled to its physical specification i.e. a PTFE pipe located within a Helmholtz coil. The Helmholtz coils were used to produce a magnetic field which was orthogonal to both the flow direction and to a chord joining the detection electrodes. At any instant in time, the magnetic flux density was uniform in the flow cross section. Using the model, the position of the electrodes could be changed to anywhere on the internal surface of the insulating PTFE wall of the flow meter to satisfy the project requirement of measuring the induced electrical potentials at specific locations on the boundary of the flow.