Convective heat-transfer measurements in liquid metals under different fluid flow conditions
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I.
INTRODUCTION
THE study of convective heat transfer has
existed since the beginning of the heat-transfer theory development. Despite the fact that an enormous quantity of theoretical and experimental results have been produced on the subject, a relatively small number of publications has reported specifically on the convective heat transfer characteristics of metal baths. The knowledge of the degree of heat transmission in a liquid metal is of great importance for many metallurgical operations. The addition of solid materials, initially at room temperature, to molten metals is a common practice in melt shops. The addition of ferroalloys to filling ladles or ladle metallurgy stations is of great industrial significance. The precise estimation of assimilation times of various ferroalloys in liquid steel requires a good knowledge of the convective characteristics of liquid steel which may be agitated by induction stirring and/or gas injection. The melting or dissolution behavior of alloying additives in nonferrous metals is also influenced by the convection in those liquid media. The dip-forming process ll'21 for the continuous casting of oxygen-free copper is another typical example of a plant operation involving solid/liquid metal contact. The erosion of furnace linings can also be attributed partly to the convective behavior of the enclosed metal bath. Consequently, the practicing engineer or researcher is quite often confronted with those kinds of problems. Generally one has to make use of existing dimensionless correlations which have been deduced from low temperature experiments (i.e., tests in air, water, and organic liquids), or have been derived from theoretical analysis (i.e., solution of the boundary layer equations, numerical solution of the turbulent Navier-Stokes equations in conjunction with heat-transfer analysis, etc.), but all these still have to be tested. Furthermore, the mathematical modeling of some metallurgical operations is very difficult because of PANAGIOTIS G. SISMANIS, formerly Postdoctoral Research Fellow with the Department of Metallurgy and Materials Science, University of Toronto, is an Engineer in Greece. STAVROS A. ARGYROPOULOS is Iron and Steel Society Professor with the Department of Metallurgy and Materials Science, University of Toronto, 184 College Street, Toronto, ON M5S 1A4, Canada. Manuscript submitted October 30, 1987.
METALLURGICALTRANSACTIONS B
uncertainties related to the exact definition of boundary conditions which are important for the solution of the relevant differential equations. Nevertheless, there is still some experimental work which has been carried out with respect to the convective heat transfer of liquid metals. Most of this work has been done on liquid mercury I3-1~ and liquid sodium, EH-~51which are low melting-point metals, and hence they present a small number of experimental difficulties. Fewer experiments have been performed on higher melting-point metals; convective heat transfer has been measured in liquid tin, l~61tinlead alloys, I~71lead, I~
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