Measuring techniques for model experiments in liquid metal alloys

Model experiments are an important tool to understand the details of the flow structure and the transport properties of flows occurring in real-scale metallurgical facilities as well as to validate the multitude of numerical codes for flow simulation. The application of suitable alloys with low melting points, for instance PbBi (T = 125 °C) or InGaSn (T = 5...10 °C), guarantees realistic flow parameters and also offers the ability to measure essential flow quantities like velocity, pressure or void fraction. Two approaches will be discussed to measure the local velocities in opaque liquid flows such as liquid metals: a mechano-optical sensor and the ultrasonic Doppler method, respectively. Today, with respect to problems like high temperatures or material compatibility both techniques reveal severe limitations considering velocity measurements in liquid steel or aluminium, however, their reliability at moderate temperatures has been demonstrated. Here, we present velocity measurements obtained by means of both methods for the case of a cylinder filled with an eutectic InGaSn melt driven by a rotating magnetic field.