Force-free and contactless sensor for electromagnetic flowrate measurements

J. Priede¹ - D. Buchenau² - G. Gerbeth²

¹ Applied Mathematics Research Centre, Coventry University, UK
² Forschungszentrum Dresden-Rossendorf, MHD Department, 01314 Dresden, Germany

Abstract
We present a novel design of a contactless flowmeter using a single cylindrical permanent magnet magnetised perpendicularly to its axis, about which it can freely rotate, and placed close to a duct with a liquid metal flow. The electromagetic torque on the magnet caused by the liquid metal flow sets the magnet into rotation. The equilibrium rotation rate, which is attained at a vanishing net electromagnetic torque on the magnet, depends only on the flowrate and the geometry of the system, while it is independent of the electromagnetic torque itself. A laboratory model of such a flowmeter has been built and tested on a liquid metal flow. Figs 4, Refs 8.