Measurement of magnitude of velocity in high-temperature liquid metals

The melting rates of metallic spheres in metal baths of the same chemical composition as the spheres were studied for various flow conditions and for isothermal systems. It has been demonstrated that the metallic sphere can be used as a probe for measuring the magnitude of the average velocity in a metal flow system over a distance equivalent to the diameter of the sphere.;The system that has been primarily investigated is the commercial purity aluminum bath under various flow conditions. Steel spheres inside steel baths have been also studied but less extensively. It has been demonstrated that the applicability of the proposed speed measurement technique is independent of the chemical composition and temperature of the melt.;The experimental calibration setups include a sphere moving with known velocity along the periphery of a circle in a metallic bath, and a stationary sphere in a rotating annular channel with molten metal. The results are typically presented in the form of calibration curves for each particular setup, where the independent variable is the average velocity of the sphere or the average velocity of the flow field, while the dependent variable is the melting time of the sphere. This presentation introduces only the experimental error of the melting time measurement, while it has the disadvantage of not generalizing the results since it refers to the specific conditions under which each set of tests was conducted. The results show that the sphere melting time is relating linearly to the flow velocity for the range of velocities of 0-40 cm/sec and for bath superheat up to 100;The study was completed by mapping an AC induction furnace with molten aluminum with respect to sphere melting times. Also, the flow field in the furnace was described mathematically and numerical results were obtained. The average flow velocities calculated experimentally for the geometric location where calibration results were available, are in good agreement with numerical results.