Eliana Ferreira Rodrigues

Numerical analysis of the liquid ejection due to the gaseous jet impact through computational fluid dynamics

Metal droplets generated by an impinging jet, play an important role in metal refining processes, mainly in oxygen steelmaking, where the droplets are ejected into the slag phase. Since the available interfacial area of droplets is very high in this process, the generated droplets enhance the rates of heat transfer and chemical reactions. Therefore, knowledge of the metal droplet generation rate, size distribution and residence time in the slag are of industrial relevance. In this work, the isothermal, transient flow of an incompressible air jet impinging onto an air/water interface at room temperature has been simulated to obtain a better understanding of the droplet ejection phenomenon. The interface was tracked throughout time using the volume of fluid (VOF) technique. The governing equations formulated for mass and momentum conservation and the k-ε turbulence model are solved in the axisymmetric computational domain using the commercial code FLUENT. The droplet ejection rates calculated with computational fluid dynamics model are compared to experimental data reported in literature, showing partial agreement, being the incompressibility assumption the probable reason for the deviation observed, which was as far pronounced as the great jet velocity. Nevertheless, the model presented shows itself as a relatively good starting point for the construction of more complex ones (with less simplifying assumptions) which should be able to offer a means to increase the understanding of the droplet ejection phenomena.

UM ESTUDO SOBRE A INFLUÊNCIA DE PROPRIEDADES FÍSICAS DA ESCÓRIA E DE PARÂMETROS OPERACIONAIS SOBRE O PROCESSO DE SLAG SPLASHING

Resumo Um modelo matemático tridimensional, via software Fluent 14.0, de modo a descrever o fluxo, em regime transiente e isotérmico dos fluidos escória e nitrogênio, foi utilizado para avaliar o comportamento de slag splashing em um convertedor a oxigênio com o propósito de reparar as regiões desgastadas do revestimento de trabalho deste reator. Para um dado padrão de sopro foi investigou-se o efeito de parâmetros tais como temperatura, densidade, viscosidade e tensão interfacial. Os resultados são comparados com dados de projeção disponíveis na literatura. Palavras-chave : Convertedor a oxigênio; Slag splashing; Modelagem matemática.

Influence of Physical Properties of Slag and Operational Parameters on Slag Splashing Process in an Oxygen Convertor

A mathematical model using Fluent 14.0 was implemented in order to describe the flow of Nitrogen and slag under transient and isothermal conditions in the slag splashing process for the improvement of refractory life. The influence of parameters affecting this process and the consequent effects on refractory linings has been investigated applying the model. For a given blow pattern, the influence of parameters such as temperature, density, viscosity and interfacial tension of the fluids involved have been discussed. The results are compared with projection data available in the literature.

Assessment of Gas‐Metal‐Slag Interaction in a Steel Making Ladle Through Physical and Mathematical Modelling

Top slag eye opening which happens as a result of gas injection is a function of the gas flow rate in addition to other factors such as ladle geometry, porous plug location as well as slag properties. Slag eye opening leads to entrapment of atmospheric nitrogen, oxygen by the steel melt affecting adversely the steel quality. In this work aspects of mixing and eye formation in steel making ladles with inert gas injection have been analyzed through physical and mathematical modeling techniques. Influence of ladle, gas flow rate and distribution and slag properties has been assessed. A correlation for estimating eye opening has been developed. Results from PIV measurements and images of eye opening obtained using a camera have been utilized to validate results from CFD simulation.