A Novel Multiphase Methodology Simulating Three Phase Flows in a Steel Ladle

Marco Ramírez-Argáez,Abhishek Dutta,C. González-Rivera,A. Conejo,A. Amaro-Villeda

doi:10.3390/pr7030175

Marco Ramírez-Argáez, Abhishek Dutta + Show 3 more

Open Access

https://doi.org/10.3390/pr7030175

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Abstract

Mixing phenomena in metallurgical steel ladles by bottom gas injection involves three phases namely, liquid molten steel, liquid slag and gaseous argon. In order to numerically solve this three-phase fluid flow system, a new approach is proposed which considers the physical nature of the gas being a dispersed phase in the liquid, while the two liquids namely, molten steel and slag are continuous phases initially separated by a sharp interface. The model was developed with the combination of two algorithms namely, IPSA (inter phase slip algorithm) where the gas bubbles are given a Eulerian approach since are considered as an interpenetrating phase in the two liquids and VOF (volume of fluid) in which the liquid is divided into two separate liquids but depending on the physical properties of each liquid they are assigned a mass fraction of each liquid. This implies that both the liquid phases (steel and slag) and the gas phase (argon) were solved for the mass balance. The Navier–Stokes conservation equations and the gas-phase turbulence in the liquid phases were solved in combination with the standard k-ε turbulence model. The mathematical model was successfully validated against flow patterns obtained experimentally using particle image velocimetry (PIV) and by the calculation of the area of the slag eye formed in a 1/17th water–oil physical model. The model was applied to an industrial ladle to describe in detail the turbulent flow structure of the multiphase system.

Highlights

Ladle steelmaking plays a key role in producing high quality steel grades
The three-phase fluid flow model representing a typical gas-stirred steel ladle consists of a combination of two algorithms namely, Inter penetrated slip algorithm (IPSA) for an interpenetrating liquid and a gas phase and the split of the liquid into two liquids separated by a sharp interface by using the volume of fluid (VOF)
A comprehensive mathematical model has been developed with an improved methodology to study multiphase flow applying two algorithms, IPSA and VOF using the computational fluid dynamics (CFD) code PHOENICS

Summary

Introduction

Ladle steelmaking plays a key role in producing high quality steel grades. The efficiency of metallurgical reactions, such as degassing, deoxidation, and desulphurization that is, the refining capacity of a steel ladle in gas stirred ladles is related to mixing phenomena. Several mathematical models have been used to investigate mixing phenomena in gas-stirred ladle systems. These models have been classified into three types: Quasi-single or pseudo-single phase models, Eulerian–Lagrangian two-phase models and Eulerian–Eulerian two-phase models. Mazumdar and Guthrie [1] compared the three mathematical modeling approaches and concluded that in terms of the velocity fields all models provide good agreement with the experimental observations. They reported that the major limitation of current models is the unrealistic prediction of turbulence parameters such as the turbulent kinetic energy. Detailed reviews of modeling-based simulation studies in ladles can be found in [2,3,4]

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