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TRANSPORT FROM CONTINUOUSLY MOVING MATERIALS UNDERGOING THERMAL PROCESSING

DOI: 10.1615/AnnualRevHeatTransfer.v4.60
pages 187-245

Yogesh Jaluria
Department of Mechanical and Aerospace Engineering Rutgers, The State University of New Jersey Piscataway, NJ 08854, USA

Abstract

This chapter presents a detailed consideration of the transport processes associated with a continuously moving material undergoing thermal processing. This problem is of interest in processes such as extrusion, fiber drawing, hot rolling, and continuous casting. Three main approaches are outlined. The first is directed at the heat transfer in the material, assuming convective coefficients at the surface. The second solves for the flow generated by an isothermal or uniform-heat-flux moving surface, focusing on the fluid flow and not on the transport in the material. The third approach is a combination of the first two and considers the conjugate problem that couples the flow and transport in the fluid with those in the material. Therefore, this is the most realistic formulation with respect to practical materials processing systems. The flow may be treated as a boundary layer, or the full, elliptic equations may be solved. Both formulations are discussed, along with the relevant numerical procedures.
A detailed review of the work done on this problem, using the various mathematical formulations outlined above, is presented. The results obtained from several studies are outlined, and the physical mechanisms that govern the transport processes are discussed. Additional effects, such as thermal buoyancy, transients, and additional forced flow in the ambient medium, are considered. The experimental work done on this problem is also reviewed. The main focus of this chapter is on the physical considerations that are important in this and other similar thermal transport processes. Also of particular interest is a critical evaluation of the present status of information on this topic and the areas where a detailed and planned future effort is needed. Several important, new, and interesting considerations in the thermal transport from a continuously moving material are brought out, with respect to a basic understanding of the underlying physical processes as well as to practical applications in the thermal processing of materials.

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