Physical and Mathematical Modelling of Liquid Steel Fluidynamics in a Billet Caster

概要

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The aim of the present work is to achieve a better understanding of the liquid steel flow patterns in a billet mould when is fed by a misaligned nozzle using two important tools analysis, physical and mathematical modelling. The numerical model includes the government Navier-stokes equations, the k-ε model, and the VOF model for the multiphase air/steel/flux system. These equations are solves through the segregated model embedded in FLUENT®. The physical model was built at 1:1 scale, where red ink and video recording are employed to visualize the fluidynamics. One nozzle deviation is applied towards the mould radius. The results indicate that a centred nozzle position does not guarantee symmetrical flow patterns inside the mould due to its curvature design. Because of curvature, at the normal nozzle alignment the jet trajectory is closer to the inner mould radius. Even when the nozzle deviations are small like 1° or 2°, the results show that the fluid flow consequences are significant and negatives in most of the cases. The worst cases induce an impact of the jet to one of the mould walls and a very unstable meniscus with strong vortexes formation. Under the present configuration, 1° deviation of the nozzle towards the inner mould radius is good enough to achieve symmetrical flow patterns and to obtain a better meniscus control.