Simulation of the submerged energy nozzle-mold water model system using laser-optical and computational fluid dynamics m
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INTRODUCTION
THE interest in flow-related optimizations in continuous casting is growing as the requirements relating to productivity and quality of the cast product become increasingly strict. By purposefully influencing the flow profile in the submerged entry nozzle (SEN) mold system, improvements can be made to both the internal and surface quality of the cast product. On the one hand, a calm, smooth mold level assists the uniform formation of the strand shell in circumferential direction and reduces the thermomechanical stresses in the strand shell. It also allows the homogeneous intake of casting powder into the lubrication gap between the strand shell and the mold wall and this, in turn, is essential for optimum lubrication and homogeneous heat transfer. Furthermore, casting powder is prevented from being drawn into the molten steel. Against this, however, there is the requirement that the mold level shall be heated up by the inflow of molten steel. A flow must, therefore, be generated at the mold level in order to compensate for the heat loss over the free surface and to ensure the melting of the casting powder. On the other hand, the flow beneath the recirculating flow pattern in the inlet region of the mold, which is called the primary vortex, should as far as possible assume a homogeneous velocity distribution in casting direction to assist heat transfer through the strand shell and, consequently, the uniform growth of the shell in circumferential direction. At the same time, a steady-state flow reduces and distributes the nonmetallic inclusions in the strand. ¨ RGEN ODENTHAL, Senior Engineer, and HERBERT HANS-JU PFEIFER, Head of Institute, are with the Institute for Industrial Furnaces and Heat Engineering in Metallurgy, RWTH Aachen, 52074 Aachen, Germany. INA LEMANOWICZ, Manager Plant Technology Simulation Technology, is with SMS Demag AG, 40237 Du¨sseldorf, Germany. RAINER GORISSEN, Senior Consultant, is with Vodafone TeleCommerce GmbH System Architecture, 40885 Ratingen, Germany. Manuscript submitted October 3, 2000. METALLURGICAL AND MATERIALS TRANSACTIONS B
In the interest of satisfying these requirements against a constantly increasing product range, the examination of flow phenomena is, today, part of the daily routine in steelworks. Such examinations are based on physical and numerical models, by means of which the nozzle-mold system can be recorded with regard to quality and quantity and, thus, enable direct adaptation of the nozzle shape and process parameters. The validation of numerical models acquires great significance in this respect. Since operational tests involve a great deal of time and expense, only a small amount of information is available for the validation of, for example, turbulence models. For this reason, flow-related experiments are usually restricted to water models in the scale of 1:1, in which the characteristic similarity criteria (Reynolds and Froude number) are observed and quantitative measurements are able to be performed. The measurement results enable the numerical s
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