Calibration of the Lorentz force flowmeter

Abstract

The Lorentz force flowmeter (LFF) is a measuring device utilizing localized static magnetic fields for the non-contact measurement of the flow rate in electrically conducting fluids. In case of highly aggressive or high-temperature conductive fluids, it is difficult to reproduce in a laboratory the conditions typically met in application. Hence, calibration becomes a difficult task. For the LFF used for open channel flow measurement in liquid aluminum, we adapt a robust calibration method. This method utilizes reference device calibration data to calibrate other devices. In a first step, liquid calibration involving the fluid flow is performed in a reference open channel with a given reference LFF device. In a second step, the liquid calibration characteristic is transferred from the reference LFF device to the test LFF device during a dry calibration procedure, in which liquid metal flow is replaced by the motion of solid metal bars through the magnet systems of both reference and test devices. Hence, the liquid calibration is needed once for the reference device only. This combined calibration strategy may also be applied to similar measurement devices.