Modeling of Three-phase Flows and Behavior of Slag/Steel Interface in an Argon Gas Stirred Ladle

Abstract

A Mathematical model has been developed to analyze the transient three-dimensional and three-phase flow in an argon gas bottom stirring ladle with one and two off-centered porous plugs. Multiphase Volume of Fluid (VOF) method is used to simulate the behaviors of slag layer. Numerical simulation was conducted to clarify the transient phenomena of gas injection into the molten steel. When argon gas is injected into molten steel in a ladle, the gas rising passage is formed near the plug, and then bubbles are created in the molten steel. The rising gas bubbles impinge on the slag intermittently and break the slag layer to create the slag eye. Simultaneously, the wave at the slag-steel interface was formed and the wave frequency increases with the increase of argon gas flow rate for one off-centered plug case. The modeling simulations show that the diameter of slag eye changes from 0.43 to 0.81 m when the flow rate of argon gas varies from 100 to 300 NL/min for a 220 ton ladle. The relationship between non-dimensional areas of slag eye and the modified Froude number is in good agreement with the experimental data reported in literature. At the same total gas flow rate of 300 NL/min, the two-plugs generate two eyes with the diameters of around 0.6 m. Since the significant deformation of slag layer occurs during gas stirring operation, the thickness of slag becomes thin near the slag eye and thick near the ladle wall, respectively. The downward flow velocity of steel at the slag eye periphery may be affected significantly by flow rate of Ar gas. Therefore, when the downward flow velocity would be larger, the more emulsification of slag could be expected.KEY WORDS: ladle metallurgy; slag layer behavior; three-phase flow; mathematical model.

Effect of Gas Blown Modes on Mixing Phenomena in a Bottom Stirring Ladle with Dual Plugs

“…The multiphase flow in a gas-stirred ladle was simulated by the volume of fluid (VOF) model, and the control equations were described as follows: 5,8,[31][32][33][34] (1) Continuity equation…”

Modeling of Gas-Steel-Slag Three-Phase Flow in Ladle Metallurgy: Part II. Multi-scale Mathematical Model

“…Linmin LI, 1,2) Baokuan LI 1) * and Zhongqiu LIU 1) 1) School of Metallurgy, Northeastern University, Shenyang, 110819 China.…”

“…Currently, numbers of mathematical models have been proposed to investigate the flow characteristics and slag layer behaviors in the gas stirred ladle. In an Eulerian way, Li et al 1) and Llanos et al 2) adopted the volume of fluid (VOF) approach to describe the fluid dynamics of all phases in ladle. Numerous works such as Zhang, 3) Bellot et al, 4) Mukhopadhyay et al, 5) Luo and Zhu 6) and Li et al 7) used the Eulerian discrete fluid model with inter-phase interactions to simulate the bubble plume, and the population balance model (PBM) for calculation of non-uniform bubble size is also employed.…”

Numerical Study on Flow, Temperature, and Concentration Distribution Features of Combined Gas and Bottom-Electromagnetic Stirring in a Ladle

“…However, a bare metal surface region, called the "open-eye", will be observable when the velocity of argon bubbles is large enough and the slag layer is relatively thin. The open-eye region increases the amount of oxygen dissolvable in molten steel, therefore resulting in re-oxidation and slag entrapment [8,9]. In addition, the heat loss will escalate due to the argon gas having a comparatively lower temperature than the molten steel.…”