New sensors for the velocity measurement in liquid metal processes

In many technological processes involving liquid metals or semiconductor melts the velocity fields cannot be measured due to the lack of commercial measuring techniques for opaque melts. We present two measuring techniques which have proven recently as providing reliable velocity measurements in liquid metals, at least in the temperature range up to about 700°C: the ultrasonic Doppler Velocimetry (UDV) and the contactless inductive flow tomography (CIFT). UDV is capable of delivering velocity profiles along the ultrasonic beam with a time-resolution of about 20 Hz. CIFT is based on the flow-induced modification of some externally applied magnetic field, which is measured by some array of magnetic field sensors outside of the melt. We present measurements with both techniques at the small-scale liquid metal model Mini-LIMMCAST of the continuous steel casting process. Both measuring methods give consistent results for the jets evolving from the nozzle outlets.