Transient eddy current flow metering: a calibration-free measurement technique for liquid metals

Eddy Current Flow Meters (ECFM) are widely used for the contactless measurement of the velocity of conductive fluids, but extensive calibration is necessary in order to get accurate results. The measured magnitudes or phase shifts are also influenced by the temperature dependent electrical conductivity. A new approach to this kind of velocity measurement is Transient Eddy Current Flow Metering (TEC-FM), which yields the fluid velocity without prior calibration. With this sensor concept it is possible to track the position of an imprinted eddy current system, which is moving with the same velocity as the conductive fluid, and thereby eliminating the need for additional calibration and temperature compensation. We delineate the basic principle of the technique, present one specific sensor configuration, and discuss first experimental results.