Modeling of Inclusion Removal in Ladle Refining

摘要

An Eulerian-Lagrangian model of three-dimensional unsteady multiphase flow in gas stirred metallurgical vessels has been developed and applied to simulate fluid flow, bubble behavior, and inclusion removal in a bottom-injection, gas-stirred steel refining ladle. The important effects of spatially-varying phase fractions, gas volume expansion according to the static pressure change, lift force, and turbulence generated by the bubbles are included using "user-defined-functions" in FLUENT. The calculated flow field and gas volume fraction matches well with an experiment in Wood's metal.rnThe probability of inclusion attachment to large spheroidal or spherical cap bubbles in a turbulent flow field is determined for the first time. Considering random turbulent motion, the attachment probability is 10 to 100 times higher than the conventional method neglecting turbulent random effect. Particles can also be trapped in the recirculation zone in the wake behind a large spherical cap bubble.rnFinally, the effect of gas bubbling on decreasing oxygen concentration is calculated. The deoxidization rate constant K_o is just within the range of data measured for various refining process. The models are ready to be augmented with other phenomena and applied to the understanding and design of metallurgical refining vessels.