Development of a flowmeter based on the Giant Magnetoimpedance effect

Abstract

Since the discovery of Giant Magnetoimpedance Effect (GMI) and Giant Stress-impedance Effect (GSI), there has been a lot of interest in these phenomena. These effects are based on the huge changes of the high-frequency electric impedance under the action of external agents such as magnetic field (GMI) and stress (GSI). GMI and GSI have associated a huge effect on certain ferromagnetic materials, in particular, on soft ferromagnetic materials under the optimal conditions. As we will see later on this work, impedance changes up to 80% will be reached (for the particular materials used in this work). Due to these high output changes and the simplicity to measure electric impedance in these conductors, highly sensitive sensors have been proposed for different applications. In particular, in this work, the GSI effect will be used on a soft ferromagnetic ribbon to build a flowmeter. In this work, GMI and GSI effects are characterized; optimum measuring conditions are determined in order to apply the GSI effect to the measurement of the water flow in a pipe (flowmeter); and the results and conclusions are discussed. It does not pretend to reach a commercial product, since that would be technically difficult for an undergraduate student but, hopefully, it will show if such a product would be possible to be made and if it would be worth it trying to develop that product.