Detection of Liquid Steel Fluid Patterns in the Vicinity of the Nozzle of a Continuous Casting Machine Blas Melissari and Stavros A. Argyropoulos Department of Materials Science and Engineering University of Toronto Toronto, Ontario Canada M5S 3E4 Key words: sphere-melting technique, submerged entry nozzle, continuous caster, modeling, experimental, fluid pattern, steel. INTRODUCTION Control of steel flow through a submerged entry nozzle(SEN) during continuous casting is well known to be crucial for surface quality and steel cleanliness. Various efforts have been directed in developing techniques to detect steel velocity in the vicinity of the SEN, including water modeling and high temperature work 1,2,3 . These efforts have had some success in addressing this difficult problem. Nevertheless, their potential efficacy is compromised by the complexity of their implementation. The sphere melting technique represents a less complex approach 4 . It measures localized velocity well below the bath surface at very high liquid metal temperatures. So far, this technique has been applied to liquid metals such as Aluminum, Magnesium alloy (AZ91) and Steel, to detect the magnitude of velocity. Furthermore, the sphere melting technique has been modified to also detect the direction of liquid metal velocity 5,6 . In the present paper, the sphere melting technique has been further adapted for use in a different context. Computer simulations using Flow3D, have been carried out to detect the sphere melting time at different zones around the submerged entry nozzle, thereby inferring possible different flow patterns at the different zones. As anticipated, these results revealed very different sphere melting times in the zones that were examined. These variations in sphere melting times shed new light as to flow conditions that impinge on nominal conditions. The sphere melting technique is therefore very promising in its capability to detect variations in liquid steel velocity from nominal conditions. BACKGROUND INFORMATION OF THE SPHERE MELTING TECHNIQUE IN LIQUID METALS The problem of a sphere melting in a liquid metal has been extensively studied by the authors 5,6 . In the sphere melting technique there are two steps: calibration and measurement. A mathematical model of sphere melting was developed, in order to minimize the tedious first step (i.e. calibration). The mathematical model involves the study of the melting dynamics of a sphere, initially at room temperature, immersed in a bath of the same composition. This model solves the momentum and energy equations. Experimental results are obtained by immersing spheres in a specially designed apparatus. The material system used for the validation is commercially pure Aluminum. The apparatus allows the temperature and tangential velocity of the bath to be controlled. The melting times of the immersed spheres are measured for each pair of temperature and velocity conditions. A complete description of the mathematical model as well as of the experimental setup, results and analysis can be found in Melissari and Argyropoulos 5,6 . The experimental apparatus consists of a tank revolving inside a heavily insulated electrical resistance furnace, called Revolving Liquid Metal Tank(RLMT). The temperature and velocity of the tank can be controlled, while the spheres are immersed from the top. The melting times of the spheres are measured and compared with the numerical modelling results. A schematic of the experimental apparatus as well as details of the sphere can be seen in figure 1. A photograph of the (RLMT) and the furnace can be seen in figure 2. Figures 3 and 4 show a comparison between the numerical predictions and the experimental results for Aluminum spheres with diameters of 5cm and 7cm, respectively.