AN IMPROVED FLUID-FLOW MODEL FOR SLAB TUNDISHES AND ITS COMPARISON WITH A FULL-SCALE WATER MODEL

A three-dimensional (3-D) mathematical model is developed based on the SOLA-SURF technique and the K-E two-equation turbulence model to simu late fluid flow phenomena in tundishes used in the continuous casting of slab. The free surface is treated by a kinematic equation of height function rather than assuming it to be flat. The model is designed to be executable in any IBM compatible 386 or 486 personal computer. An uneven mesh system is, therefore, employed to handle the actual dimens ions of the ladle nozzle, tundish, and submerged nozzle to the casting mold. Computed results describing the 3-D flow field, surface fluctua tion, and the residence time distribution (RTD) curve during steady-st ate operation are attempted The mathematical model is then verified wi th the measurement data obtained from a full-scale water model. The re sult is quite satisfactory. As the model proved to be reliable, a seri es of numerical experiments was then carried out. The various indexes of surface fluctuation and residence lime such as t(min), t(peak), and t(mean) obtained or derived from the RTD curves are used to evaluate the effects of the various combinations of flow, control devices on th e removal of inclusions. The results show that the characteristics of fluid flow behavior within a tundish can be varied considerably with t he use of flow control devices such as weir, dam, and dam with a hole. The information provided by the analysis can then be used to optimize the tundish design to obtain cleaner continuous casting steel slab.