Articles techniques et présentations

Working on Faraday’s law of electromagnetic induction, electromagnetic flowmeters measure flowrate on the basis of the electric potential induced when a magnetic flux interacts with flowing water. The electromagnetic coils of the flowmeter are crucial to its operation, given that the generated magnetic field should be of sufficient magnitude to ensure an adequate signal strength especially under low flow or noisy conditions. Hence, optimal design of the coils is of paramount importance, especially for large flowmeters. A multiphysics-model of the electromagnetic flowmeter with capability to simulate the magnetic flux, the fluid velocity inside the pipe and the induced electric potential or the signal was developed in COMSOL multiphysics. The model was validated with data from tests, by comparing the computed and measured signals. The model was then used to evaluate several coil designs with the purpose of maximizing the field strength. Finally, the best coil design in terms of shape and size which yielded the maximum field strength and consequently the maximum signal was chosen for fabrication and testing. Testing of the new coil design verified the model findings and showed a substantial 12% improvement in signal strength.