Mikael Ersson

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Verified

Mikael verified their affiliation via an institutional email.

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• PhD
• Professor (Full) at KTH Royal Institute of Technology

Macrosegregation defect is one of the main concerns during continuous casting which strongly deteriorates the steel quality. In this study, a mathematical model was established to investigate the effect of a novel swirling flow submerged entry nozzle (SEN) on solidification and macrosegregation behavior of a curved round bloom with the diameter of...

Swirling flow submerged entry nozzle technology is one of the important methods to optimise the continuous casting of steel. In this study, a novel swirling flow brick design in tundish was proposed to achieve a swirling flow submerged entry nozzle. Numerical simulations were carried out to investigate steel flow dynamic behaviour in a round mould...

Multi-physics thermo-fluid modeling has been extensively used as an approach to understand melt pool dynamics and defect formation as well as optimizing the process-related parameters of laser powder-bed fusion (L-PBF). However, its capabilities for being implemented as a reliable tool for material design, where minor changes in material-related pa...

Three-dimensional mathematical model was established to investigate the solidification behavior during the continuous casting of a round bloom with the diameter of 0.7 m, where a novel swirling flow submerged entry nozzle (SEN) combined with mold electromagnetic stirring (M-EMS) method was used. The results show that an impinging flow phenomenon, w...

Gas‐based direct reduction in a shaft furnace is the dominant process in the world for production of direct reduced iron. As fresh reducing gas passes through the iron ore burden, it is diluted by the gas emitted from the reacted iron ores which decreases the reduction potential of the reducing gas. Previous reduction experiments mostly used single...

Gas-blowing technology is widely used in converter steelmaking to homogenize liquid steel and accelerate chemical reactions, with Argon oxygen decarburization (AOD) being the dominant process for stainless steelmaking. Due to the harsh environment, it is advisable to study the phenomenon using small-scale physical models and numerical simulations b...

In metallurgical converter processes, numerical modeling is a useful tool for understanding the complexity of the systems. In this paper, we present a practical model that couples fluid dynamics and chemical reactions to explore the impact of mixing time on decarburization. Using computational fluid dynamics (CFD), in this study, we investigate an...

Bath stirring, degassing, and decarburization in steel refining are strongly related to flow behaviors. The bubble plume produced in Ruhrstahl–Heraeus (RH) up‐snorkel plays an important role during refining, since it not only acts as a bubble pump, but also provides the reaction interface. Herein, it is aimed to form a new flow pattern in the up‐sn...

Flow field, heat transfer and inclusion behavior in a 700 mm round bloom mold under the effect of a swirling flow submerged entry nozzle (SEN) were investigated with the aim to enhance the casting process. The results indicate that the impinging flow phenomenon, which is commonly observed in conventional single-port SEN casting, was completely supp...

A three-dimensional mathematical model was developed to investigate the effect of gas blowing nozzle angles on multiphase flow, circulation flow rate, and mixing time during Ruhrstahl-Heraeus (RH) refining process. Also, a water model with a geometric scale of 1:4 from an industrial RH furnace of 260 t was built up, and measurements were carried ou...

Mixing plays a key role in mass and heat transfer, as well as chemical reactions in various vessels involving agitation. Several studies have confirmed that the mixing time obtained from several monitor locations cannot reflect the mixing time for the whole bath because stirring situation in different locations is variable due to the change of oper...

Three-dimensional computational fluid dynamics simulations were carried out to investigate the multiphase flow and heat transfer in a round mold, when using swirling flow generator (SFG) designs in a tundish. The results show that an impinging flow in the mold is significantly suppressed by using a SFG design, compared to when using a conventional...

Metallurgical converters such as the Argon Oxygen Decarburization (AOD) converter generally utilize gas blowing for the mixing and refinement of liquid steel. Due to the harsh environment of the complex and opaque system, it is common practice to study the stirring of the process through physical and numerical models. Effective mixing in the bath h...

Casting is a vital process in steel production where solidification process of molten steel occurs in mold coupled with fluid flow, heat transfer, crystal growth, inclusion motion, solute redistribution, segregation, and so on. All these phenomena are closely related to the steel flow behavior. In order to optimize the flow field in mold at initial...

The current study focuses on the cavity formation induced by jet impingement with the help of numerical simulations based on a deformed mesh method. The interface between the liquid phase and gas phase separates the calculation domain into two single-phase domains, which exchange momentum data except for mass transfer. For the subsonic jet flow, th...

Small scale physical models are commonly used to investigate gas stirred processes in steelmaking practice. The Argon Oxygen decarburization (AOD) converter is among various processes widely used in the metallurgy field and utilizes side-blowing of oxygen and inert gas for mixing in the bath. This study investigates the effect of the converter incl...

High turbulence at the liquid steel‐mold flux interface can result in mold flux entrapments, which can generate non‐metallic inclusions during the ingot casting process. Those non‐metallic inclusions are detrimental to the final steel quality. The teeming process during ingot casting is typically carried out using the uphill teeming method. The aut...

The flow pattern affects the interaction between the mold flux and liquid steel, especially during the initial entry of liquid steel into the mold. Strong turbulence can cause mold flux entrapments during the ingot casting process. If this happens, nonmetallic inclusions are generated, which decreases the quality of the final product. Herein, the s...

The flow behavior of gas in compressible and incompressible systems was investigated at an ambient temperature in an air–water system and at an operating process temperature in the IronArc system, using computational fluid dynamics. The simulation results were verified by experiments in the air–water system and established empirical equations to en...

The wear of industrial refractory materials was studied in contact with slag containing high amounts of FeO using the rotating finger technique. The thermodynamic equilibrium of the refractory slag systems was also determined in Thermo-calc® and FactSage™. The studied refractories were alumina spinel, zirconia, graphite, silicon carbide (SiC), magn...

The IronArc process is a novel approach to ironmaking which aims to reduce the associated \({\hbox {CO}}_{2}\) emissions. By superheating gas using electricity in a plasma generator (PG) the heat required for the process can be supplied without burning of coke. Reduction of hematite and magnetite ores is facilitated by additions of hydrocarbons fro...

In this study, the volume of fluid (VOF) model is applied to simulate the phenomenon caused by the bubble motion from the molten metal into a slag. First, the mathematical model is validated by the experimental data from the literature. Then, the model is used to quantitative predict the process of a single argon bubble passage from the liquid stee...

In this numerical study, the variations in the surface area of the cooling channels in a solid oxide fuel cell with different cross sections and multi-walled carbon nanotubes oil/MWCNT nanofluid volume fractions are considered. Rectangular, trapezoidal and elliptical cross sections, and nanofluid volume fractions of 0–6% for the fluid are chosen as...

The generation of non‐metallic inclusions due to mold flux entrapment is detrimental for the final steel quality in the uphill teeming process. In this study, physical and mathematical modelling using a full scale mold is carried out to investigate the change of the hump height and the surface height at the free surface during filling. Moreover, th...

This research investigates a numerical simulation of swirling turbulent non-premixed combustion. The effects on the combustion characteristics are examined with three turbulence models: namely the Reynolds stress model, spectral turbulence analysis and Re-Normalization Group. In addition, the P-1 and discrete ordinate (DO) models are used to simula...

A kinetic model was developed to describe multicomponent reactions and mass transfer at the steel/molten flux interface under the effect of the interfacial tension. This model mainly describes the following interfacial physicochemical phenomena: i) Silica decomposition and oxygen adsorption at the interface, ii) Oxygen and titanium reactions at the...

The bubbly flow and mixing conditions for gas stirring in a 50t ladle were investigated by using physical modelling and mathematical modelling. In the physical modelling, the effect of the porous plugs’ configurations on the tracer homogenization was studied by using a saturated NaCl solution to predict the mixing time and a color dye to show the m...

In this paper, we present a numerical simulation of a laminar, steady and Newtonian flow of f-graphene nanoplatelet/water nanofluid in a new microchannel design with factors for increasing heat transfer such as presence of ribs, curves to enable satisfactory fluid mixing and changing fluid course at the inlet and exit sections. The results of this...

Effect of a swirling flow SEN (submerged entry nozzle) outlet design on the multiphase flow and heat transfer in a mould was investigated by using numerical simulation. It was found that different SEN outlet designs could form different flow patterns and temperature distributions on the upper of the mould. The enlarged outlet SEN design had an effe...

The flow pattern plays a crucial role in the uphill teeming process. The non-metallic inclusion generation due to interaction with the mold flux is believed to be influenced by the flow pattern. In this study, a three-dimensional mathematical model of the filling of a gating system for 10, 20, and 30 degrees angled runners was used to predict the f...

Numerical modeling was used to study the capability of postcombustion in an electric arc furnace (EAF) equipped with virtual lance burners. The CO flow rate at the molten bath surface was estimated using the off-gas data obtained close to the outlet of an EAF. Then, the effect of the secondary oxygen flow rate on postcombustion was studied. The res...

IronArc is a newly developed technology and an emerging future process for pig iron production. The long-term goal with this technology is to reduce the CO2 emissions and energy consumption compared to existing technologies. The production rate of this process is dependent on the stirring, which was investigated in the pilot plant process by measur...

A simple method to be used for colocated pressure-velocity coupling in incompressible flows is presented with a full derivation. A number of standard test cases are shown that demonstrate the ability of the method to produce accurate results. The method avoids spurious pressure oscillations while keeping the pressure Poisson equation stencil compac...

A simple method to be used for colocated pressure-velocity coupling in incompressible flows is presented with a full derivation. A number of standard test cases are shown that demonstrate the ability of the method to produce accurate results. The method avoids spurious pressure oscillations while keeping the pressure Poisson equation stencil compac...

This article presents a review of the research into gas stirring in ladle metallurgy carried out over the past few decades. Herein, the physical modeling experiments are divided into four major areas: (1) mixing and homogenization in the ladle; (2) gas bubble formation, transformation, and interactions in the plume zone; (3) inclusion behavior at t...

The effect of the immersion depth of a new swirling flow tundish SEN (Submerged Entry Nozzle) on the multiphase flow and heat transfer in a mold was studied using numerical simulation. The RSM (Reynolds Stress Model) and the VOF (Volume of Fluid) model were used to solve the steel and slag flow phenomena. The results show that the SEN immersion dep...

One of the most important parameters for gas injection into liquid baths is the penetration depth of the gas into the bath. This is due to that it strongly influences the flow structure and hence the stirring and plume behavior in metallurgical processes. The IRONARC process is a new energy efficient process for reduction of iron oxide to produce p...

The effect of a new cylindrical swirling flow tundish design on the multiphase flow and heat transfer in a mold was studied. The RSM (Reynolds stress model) and the VOF (volume of fluid) model were used to solve the steel and slag flow phenomena. The effect of the swirling flow tundish design on the temperature distribution and inclusion motion was...

IronArc is a newly developed technology for pig iron production with the aim to reduce the CO2 emission and energy consumption, compared to a conventional blast furnace route. In order to understand the fluid flow and stirring in the IronArc reactor, water modeling experiments are performed. Specifically, a down scaled acrylic plastic model of the...

The focus of the study is experimental setups and conditions leading to pyro-lysis (cracking) of such gaseous hydrocarbons as methane, mixed propane andbutane, at the temperatures of the heater below 200 ̊C. The process was me-chanically assisted by putting the substances being decomposed into a d y-namic interaction with the fractal interfaces of...

Different sizes and shapes of nonmetallic inclusions in a swirling flow submerged entry nozzle (SEN) placed in a new tundish design were investigated by using a Lagrangian particle tracking scheme. The results show that inclusions in the current cylindrical tundish have difficulties remaining in the top tundish region, since a strong rotational ste...

A swirling flow producer was designed for a conventional tundish in order to produce a swirling flow in the SEN driven by the steel flow potential. CFD simulations were carried out to investigate the flow phenomena in the new tundish system. The results show that a swirling flow in the tundish SEN was successfully obtained. The swirl number of the...

The swirling flow has widely been investigated for liquid steel flowing in the continuous casting process. In this paper, a new design of the submerged entry nozzle (SEN) is applied by using a reverse TurboSwirl device with a divergent nozzle. This divergent reverse TurboSwirl nozzle (DRTSN) is shown to gain a more beneficial flow pattern compared...

A new tundish design was investigated using both water model experiments and numerical simulations. The results show that the Reynolds Stress Model simulation results agree well with the Particle Image Velocimetry-measured results for water model experiments. A strong swirling flow in the Submerged Entry Nozzle (SEN) of the new tundish was successf...

Over the last few decades, a number of CFD models have been dedicated to increasing the understanding of the decarburization processes in steelmaking. However, these processes are highly complex with large variations in time and length, and this makes the systems extremely demanding to simulate. Several reports have been published where parts of th...

Inclusion behavior during a ladle teeming process is investigated. A Lagrangian method is used to track different-size inclusions and to compare their behaviors in steel flows, solved by the realizable k-ε model with SWF (Standard Wall Function), realizable k-ε model with EWT (Enhanced Wall Treatment), and RSM (Reynolds Stress Model). The results s...

A new method of preventing slopping is proposed in this paper, by simply blowing gas at the top of the foam surface. The physical experiment results show that the foam height can be effectively decreased by the top blowing air. The maximum decrease of the foam height can reach around 70 mm with an initial foam height of 145 mm in the current setup,...

The inclusion removal mechanism due to a bubble wake flow was studied using a water model and a three dimensional numerical model. In the experiments, a high-speed camera was used to record the bubble movement and the inclusion behavior connected to the flow. In the numerical model, the bubble induced fluid dynamics in the liquid was simulated usin...

The use of available and cheap industrial producer gases as alternative fuels for the steel reheating furnaces is an attractive topic for steel industry. The application of producer gases for such furnaces introduces not only the complicated combustion system of Low Calorific Value (LCV) gases, but also several impurities that could be problematic...

As an alternative to some traditional methods to generate a swirling flow in the continuous casting process, the use of a new swirling flow generator, TurboSwirl, is studied. Specifically, a reversed TurboSwirl device is designed as part of a submerged entry nozzle (SEN) for a round billet continuous casting process. Mathematical modeling is used t...

A flow in a horizontal channel is an important method for the transport of materials, products and/or waste gases/liquids. The deposition of particles in a horizontal channel may clog the flow path. The purpose of this paper is to extend the use of a developed Eulerian deposition model to liquid flows in horizontal straight channels to predict the...

A swirling flow has been demonstrated to be beneficial for making the flow pattern even and to reduce turbulence during filling in ingot casting. A new swirling flow generation device, TurboSwirl, was applied to improve the flow pattern of the liquid steel as it flows into the mold so that a more stable flow could be obtained. A water model was bui...

The behaviors of non-metallic inclusions in a new tundish and SEN design enabling a swirling flow are investigated by using a Lagrangian particle tracking scheme. The results show that 99% of both Al2O3 and Ce2O3 inclusions are removed from both the top surface and the other tundish walls with a “trap” boundary condition, while only around 60% are...

A new tundish is designed with the aim to produce a swirling flow in a tundish SEN by an economical way of using the steel flow potential as the required power. This design is easily obtained by adding a cylindrical part of the tundish onto a traditional tundish. The results show that a swirling flow in the SEN of the new tundish is successfully ob...

During the past decades, combustion of producer gases from other facilities has been introduced as one of the promising techniques in steel furnaces. The impurities inside producer gases are responsible for a low quality steel production due to formation of the molten ash that forms sticky layers of solutions on steel surfaces. Therefore, a compreh...

The paper focuses on the fundamental aspects of the kinetic energy transfer from a top and bottom gas injection to the bath of the basic oxygen furnace (BOF) by applying a mathematical model. The analyses revealed that the energy transfer is less efficient when top lance height is lowered or the flowrate is increased in the top blowing operations....

To produce high-quality ingot cast steel with a better surface quality, it would be beneficial for the uphill teeming process if a much more stable flow pattern could be achieved in the runners. Several techniques have been utilized in the industry to try to obtain a stable flow of liquid steel, such as a swirling flow. Some research has indicated...

The use of TurboSwirl to obtain an improved steel cleanliness during filling of an ingot was numerically studied by VOF and DPM models. It was found that a radius-reduced TurboSwirl or a proper tapered mold entrance nozzle with an adequate developed region for steel flow can reduce the risk of mold flux entrapment in a mold. The ingot casting proce...

The bubble formation during gas injection into liquids was studied using a water model and a three-dimensional numerical model. In the experiment, a high-speed camera was used to record the bubble formation processes. Nozzle diameters of 0.5, 1, and 2 mm were investigated under both wetting and non-wetting conditions. The bubble sizes and formation...

Ingot casting is widely used to produce some certain specialty steel grades. During the process of teeming the liquid steel from the ladle to the mould for a final solidification, the high velocity of the liquid steel can result in an uneven flow pattern either in the vertical and horizontal runners or in the mould. This can cause some serious prob...

Gas is often injected into molten steel by various devices, typically through tuyeres or porous plugs. This increases the thermal and chemical homogenization of the melts as well as helps to remove inclusions from the steel bath. The bubble formation from the gas injection devices is a key step in these operations. Therefore, it is necessary to mak...

In the preceding work, the inclusion behavior in a submerged entry nozzle (SEN) and mold induced by using a swirl flow has been investigated. The results showed that a swirl flow can effectively promote the inclusions removal to the meniscus as well as reduce the inclusions entrapment at the solidified shell wall. Moreover, that the swirl flow was...

In this study, a side tuyere was introduced to investigate how it is possible to lower the mixing time and to avoid problems of a reduced stirring when using the application of slag splashing process in the combined top and bottom blown converter. Both physical and mathematical models were applied to study the flow in the bath. Specifically, the ef...

The fundamental aspects of rising argon bubbles in molten metal for a laminar flow were investigated by numerical simulations. The Volume-of-Fluid (VOF) model was used to track the interface between argon and liquid metal. The process of a bubble rising in the molten metal includes two steps, one is the bubble rising inside the liquid, and the othe...

A 1/6th scaled down physical model was used to study and optimize the stirring condition of a 30 t converter. A number of parameters were studied and their effects on the mixing time were recorded. A new bottom tuyere scheme with an asymmetrical configuration was found to be one of the best cases with respect to a decreased mixing time in the bath....

We report experimental setups and conditions leading to pyrolysis (cracking) of such gaseous hydrocarbons as methane, mixed propane and butane, at the temperatures of the heater below 200 oC. The process was mechanically assisted by putting the substances being decomposed into a dynamic interaction with the tin and bismuth alloy. The alloy had peri...

Nozzle clogging caused by the build-up of non-metallic inclusions on ceramic walls is a serious industrial problem during continuous casting of steel. The current theoretical study uses the extended Eulerian model to predict the inclusion deposition rate in a submerged entry nozzle (SEN). The model considers Brownian and turbulent diffusion, turbop...

An investigation on the post-combustion phenomena in an argon oxygen decarburization (AOD) system containing a converter and a flue has been conducted. An AOD converter is mainly characterized by nozzles installed at the lower side of the converter. The nozzles are intended to inject the decarburization gas of oxygen mixed with an inert gas such as...

The deposition of non-metallic particles in liquid-metal flows is a serious industrial problem because the build-up of particles on ceramic walls clogs the flow path and interrupts the production, and this leads to large economic losses. This paper is an effort to extend the current state-of-the-art knowledge of particle deposition in air in order...

Previous studies have verified that a swirl flow generated in a submerged entry nozzle (SEN) can effectively improve a flow pattern and a heat transfer in a continuous casting (CC) process. In order to obtain a further in-depth understanding with respect to the effect of a swirl flow on a CC process, the inclusion behavior in a SEN and a mold was s...

A mathematical model of a top blown converter, which was based on a physical model of a 30 t vessel, was developed in this study. A simplified model consisting of the converter was used in the mathematical simulation. With the simplified model, it is possible to run a large number of tracer calculations within a short time, compared to solving for...

The flow pattern has widely been recognized to have an impact on the exogenous non-metallic inclusion generation in the gating system and mold flux entrapment in the mold in the uphill teeming process. The possible solutions of the flow pattern control are required to be reliable and practical in order to improve the yield and the ingot quality in...

Steel flow phenomena and Ce2O3 inclusion behavior are presented in this paper. A three-dimensional model was developed to describe the steel flow phenomena and the inclusion behavior during a teeming process. The Kim-Chen modified k-ɛ turbulent model was used to simulate the turbulence properties and the Height-of-Liquid model was used to capture t...

Numerical modeling has been used to investigate the influence of electromagnetic stirring on melting of a single piece of scrap in an eccentric bottom tapping (EBT) electric arc furnace (EAF). The heat transfer and fluid flow in the melt for both conditions with and without electromagnetic stirring were studied. The buoyancy and electromagnetic for...

The flow pattern in the uphill teeming process has been found to be closely related to the quality of ingots regarding the formation of non-metallic inclusions and entrapment of mold flux. The filling conditions can be improved by the utilization of a swirl blade in the runner. The emphasis of this study is to investigate the flow pattern of steel...

Studies of physical phenomena in a jet caused by VOD (Vacuum Oxygen Decarburization) nozzles have been carried out. The VOD process is a metallurgical process where the steel-making route is controlled under vacuum environment with oxygen top blowing. In this work, two VOD nozzle models have been employed for an investigation based on two real De L...

The flow pattern in the uphill teeming process has been found to be closely related to the quality of ingots and further affects the yield of ingots production, which is crucial for steel making process. The formation of non-metallic inclusion and entrapment of mold flux has been considered to be affected by the flow pattern in the gating system an...

This study has focused on numerically exploring the oxygen flow in the convergent-divergent De Laval nozzle. The De Laval nozzle has been commonly used as oxygen outlet at the lance tip in the vacuum oxygen decarburization (VOD) process. The nozzle geometry used in an active VOD plant was investigated by isentropic nozzle theory as well as by numer...

Previously a first dynamic modeling approach, where a computational fluid dynamics software is coupled to a thermodynamics software to obtain simulations of reactions between steel, slag and gas in a top-blown converter has been presented. In the current model improvement, a more realistic model has been developed, where the number of gas species a...

A fundamental mathematical model of the flow field and surface deformation caused by an impinging jet in a top blown reactor has been developed. The results have been validated against water model experiments. More specifically, the predicted penetration depth has been found to agree well with surface deformation measurements and predictions using...

A novel modeling approach is presented where a computational fluid dynamics software is coupled to thermodynamic databases to obtain dynamic simulations of metallurgical process phenomena. The modeling approach has been used on a fundamental model of a top-blown converter. Reactions between gas-steel, gas-slag, steel-slag and gas-steel-slag have be...

Physical modeling was done to study the flow field in a cylindrical bath agitated by bottom purging, top lance blowing and a combination of both injection types. A particle image velocimetry (PIV) system has been used to capture the velocity field of all three cases mentioned above. Special attention was paid to the recirculation loop. Top blowing...

A fundamental mathematical model of lance blowing on a bath surface has been developed with a purpose to increase the understanding of various phenomena in top blown oxygen converters, The model is based on the Navier-Stokes equations and turbulence is predicted using the k-s model. In the present model the deformation of the liquid surface, caused...