Experimental and numerical investigation of the transient meniscus behaviour in a continuous caster

Abstract

This is a project to develop a dynamic CFD model of the continuous caster mould region with the aid of an experimental water-model configuration. The emphasis will be on hydrodynamic aspects of the slag/steel interface behaviour and in particular the effects of injected gas bubbles on interface stability. The model includes an improved implicit Counter Diffusion Method (CDM) interface-tracking scheme for numerical efficiency and a Lagrangian representation of argon bubble tracks. In the water model, an oil layer is used to represent the slag. Qualitative evaluation of the results against water model visualizations explains the main flow patterns observed, and validates the predicted deformation of the meniscus. Quantitative comparison against LDA velocity measurements is provided at seven measurement positions and the nature of observed wave action is analyzed by its spectral pattern. The dominant frequencies measured are correlated against the turnover time of the top and bottom recirculation regions in the caster for various SEN casting velocities and gas flow rates. The effect of gas is seen to have an important influence on the flowfield in general, but also on interface behaviour and on the frequencies observed. This influence is also seen in the case of a real industrial continuous caster, where velocity measurements and simulations show a change in the steel velocity pattern from a “single roll” to a “double roll” as the relative amount of gas increases