Melt velocity measurement by a noncontacting electromagnetic probe

Abstract

A novel method of the velocity measurement of melt was developed on the basis of electromagnetic principles. Two sensors were designed to measure the velocity of melt without direct contact. One, the electromagnetic velocity sensor (EMVS) consists of an electromagnet and a magnetic probe, and the other, the permanent magnet velocity sensor (PMVS) consists of a ring-shaped permanent magnet and a magnetic probe. These velocity sensors were tested with an aluminum cylinder and a Wood metal melt. The magnetic flux densities obtained by the velocity sensors were proportional to the rotating speed of the aluminum cylinder up to 1.5 m/s and the stirring speed of the Wood metal melt up to 0.8 m/s. The calculated magnetic-flux density near the velocity sensor was in good agreement with the measured one. The distribution of the magnetic field of the EMVS was more favorable in obtaining a larger sensor signal than the PMVS. (C) 2000 American Institute of Physics. [S0034-6748(00)05405-8].