Turbulent recirculating flow in induction furnaces: A comparison of measurements with predictions over a range of operat
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INTRODUCTION
IN recent years there has been a growing interest in the development of an improved basic understanding of heat and fluid flow phenomena in induction furnaces. The now well-established modeling approach to these problems involves the solution of Maxwell's equations to describe the electromagnetic force field, which is then combined with the turbulent Navier-Stokes equations to represent the velocity field. In general, the k-e model has been used to represent the turbulent behavior; thus this approach provides information on the velocity field and on the maps of the turbulent kinetic energy and rate of energy dissipation.~-l~ Overall, there appears to be a consensus that this is a reasonable way to model the turbulent behavior for engineering-type calculations for turbulent recirculating flows; indeed, there is some experimental evidence to support these computed results. The experimental work reported to date falls in two categories: (a) The measurement of the surface velocity and tracer dispersion rate (either in the laboratory or under industrial conditions). 1,2.10 (b) The measurement of flow patterns, the mean and turbulent fluctuating velocities, n.~2.13 Up to the present time most of the data reported fall in the first category and these appear to be in good agreement with predictions obtained using numerical methods. Clearly, measurements involving more than just the surface velocity and data obtained over a broader range of operating conditions would provide a much more rigorous test of the mathematical models currently used. This assessment would be highly desirable because in many, more sophisticated applications of induction stirring N. EL-KADDAH, formerly of the Department of Materials Science and Engineering at MIT, is now Associate Professor of Metallurgical Engineering at the University of Alabama, Tuscaloosa, AL 35486. J. SZEKELY is Professor of Materials Engineering at Massachusetts Institute of Technology, Cambridge, MA 02139. Y. FAUTRELLE and E. TABERLET are Maitre d'Assistants and Graduate Student, respectively, at the Institut de Mecanique de Grenoble. Domain Universitaire, Grenoble, France. Manuscript submitted May 21, 1985.
METALLURGICAL TRANSACTIONS B
one would need knowledge beyond just the velocity distribution in the system. As an example, the coalescence of inclusions depends on the rate of turbulence energy dissipation, 14 as will the rate at which alloying elements are dissolved in an agitated melt. l0 Furthermore, the morphology of solidified structures may also be affected by the flow conditions in agitated fluid system. In recent papers Moore and Hunt ll published the first detailed measurements on the velocity field and on the turbulent fluctuating velocity in a mercury pool agitated by a single phase induction coil, operating at a 50 Hz frequency. The mean flow observed consisted of two recirculating loops, and the position of the vortex was independent of the intensity of applied magnetic field Bo (i.e., coil current). They also found that the linear velocity
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