A CFD model based on water model experiments has been created to simulate slag entrainment and droplet formation. Multiphase Volume of Fluid (VOF) method is used to track the interface between slag and steel and User Defined File (UDF) code is applied to track separate droplets. Four oil-water systems and three slag-metal systems were simulated. The main objective of this research was to obtain droplet diameter distributions and the average droplet diameter in several different cases. With slag-metal cases the main interest was the effect of interfacial tension to droplet formation. With oil-water systems we studied the effect oil layer width and oil viscosity. The obtained droplet diameter distributions show that the dominant droplet size is 2-3 mm in every oil-water systems. In slag-metal systems the dominant size varies between 1-2 mm and 2-3 mm. The simulations show also that the average droplet size in all cases is 2.78-3.63 mm. The results were compared to the studies available in the literature.

In secondary steelmaking, the optimal size and position of open-eye is important for effective alloying practice. In the current work, the effect of the top layer thickness and density on the formation of open-eye in a gas stirred ladle was investigated. A one-fifth scale water model of 150-ton ladle was established with single and dual plug configurations for the physical modeling measurements. Air, water and three different oils were used to simulate the argon, liquid steel and slag in the water model, respectively. A transient Computational Fluid Dynamics (CFD) model based on Eulerian Volume of Fluid (VOF) approach was developed for numerical modeling of the fluid flow behavior. The physical modeling results show that the relative open-eye area decreases from 46.7 to 5.6% when top layer thickness was increased from 0.75 to 7.5 cm using a gas flow rate of 7.5 NL min À1 . The effect of the number of plugs on the open-eye area for the same range of top layer thickness mentioned above was also studied. The relative open-eye area generated due to the gas injection through the dual plugs decreased from 49.9 to 5.8%. To study the effect of top layer properties, rapeseed oil, castor oil and paraffin oil were employed for studying the effect of density and dynamic viscosity on the open-eye formation. The results revealed that a larger open-eye is formed when the density is increased. Furthermore, it was found out that the density of the upper phase dominates the open-eye formation while dynamic viscosity has only minor effect. The results obtained from numerical simulations and physical modeling were found to be in good agreement.

Computational fluid dynamics (CFD) simulations have been carried out to study interfacial velocity and its effect on slag emulsification at the steel–slag interface. The multiphase volume of fluid (VOF) method was used to track the interface between slag and steel and a user defined function (UDF) was applied to calculate the interfacial velocity and to track separate droplets. Slag entrainment based on composition adjustment by sealed argon bubbling‐oxygen blowing (CAS‐OB) process was simulated using different inlet velocities of steel. The main objective of the present work was to study how steel flow velocity effects droplet distributions. Continuous Rosin–Rammler–Sperling (RRS) distribution function was fitted to computational results in order to provide a quantitative description of the droplet size distribution. The generation rates of the interfacial area between slag and steel were estimated based on obtained RRS‐distributions. The Sauter diameter was found to vary between 4 and 6 mm and the generation rate of the interfacial area between 0.2 and 0.6 m2 s−1. The results agree well with previous studies presented in the literature.

A process model was proposed by Järvinen and co-authors for modelling the side-blowing decarburisation stage of the Argon-Oxygen Decarburisation (AOD) process. Here, a new model for the reduction stage has been derived and coupled with the earlier-developed model. The model considers mass-transfer controlled reversible reactions between the steel bath and the top slag. The effect of emulsification phenomena on the total reaction area and on the mass and heat transfer characteristics have been taken into account. The effects of various additions on the mass and heat balance have also been considered. The paper is divided into two parts: Part I presents the derivation of the model, while Part II considers validation of the model with full-scale production data from a 150 t AOD converter at Outokumpu Stainless Oy, Tornio Works, Finland.

The objective of this work was to develop a process model for the CAS-OB (Composition Adjustment by Sealed argon bubbling-Oxygen Blowing). The CAS-OB is designed to homogenize and control the steel composition and temperature before the casting. In the heating mode (OB) studied here, a refractory bell is lowered and submerged 30 cm below the liquid steel surface of the ladle and under this well-defined sealed volume, oxygen gas is injected to oxidize solid aluminum particles that are fed and molten at the surface. Under consideration were the melting of the solid aluminum particles, the oxidation of pure molten aluminum, and the oxidation of dissolved species, in this case Al, Mn, C and Si, and the solvent Fe. We also considered the formation and oxidation of steel droplets formed in the blowing when they pass through and react with the surface slag and also the reaction of pure aluminum on the top of the slag layer. Based on our simulations, only 30-40% of the chemical energy can be used to heat up the steel. A fraction of 0.8-0.85 of the O2 can be utilized in the process; these values correspond to those obtained in previous work. The main part of the heating energy comes from the oxidation of the fed Al. FeO is primarily an intermediate product of the reactions. The model was tested against industrial trials for steel temperature and compositions of slag and steel, and it succeeded in capturing correct trends and absolute accuracy within the analyzing accuracy.