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Liu, Y., Ersson, M., Liu, H., Jönsson, P. G. & Gan, Y. (2019). A Review of Physical and Numerical Approaches for the Study of Gas Stirring in Ladle Metallurgy. Metallurgical and materials transactions. B, process metallurgy and materials processing science, 50(1), 555-577
Open this publication in new window or tab >>A Review of Physical and Numerical Approaches for the Study of Gas Stirring in Ladle Metallurgy
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2019 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 50, no 1, p. 555-577Article, review/survey (Refereed) Published
Abstract [en]

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 the steel-slag interface and in the molten steel; and (4) open eye formation. Several industrial trials have also been carried out to optimize gas stirring and open eye formation. Approaches for selecting criteria for scaling to guarantee flow similarity between industrial trials and physical modeling experiments are discussed. To describe the bubble behavior and two-phase plume structure, four main mathematical models have been used in different research fields: (1) the quasi-single-phase model, (2) the volume of fluid (VOF) model, (3) the Eulerian multiphase (E-E) model, and (4) the Eulerian-Lagrangian (E-L) model. In recent years, the E-E model has been used to predict gas stirring conditions in the ladle, and specific models in commercial packages, as well as research codes, have been developed gradually to describe the complex physical and chemical phenomena. Furthermore, the coupling of turbulence models with multiphase models is also discussed. For physical modeling, some general empirical rules have not been analyzed sufficiently. Based on a comparison with the available experimental results, it is found that the mathematical models focusing on the mass transfer phenomenon and inclusion behaviors at the steel-slag interface, vacuum degassing at the gas-liquid interface, dissolution rate of the solid alloy at the liquid-solid interface, and the combination of fluid dynamics and thermodynamics need to be improved further. To describe industrial conditions using mathematical methods and improve numerical modeling, the results of physical modeling experiments and industrial trials must offer satisfactory validations for the improvement of numerical modeling.

Place, publisher, year, edition, pages
SPRINGER, 2019
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-243935 (URN)10.1007/s11663-018-1446-x (DOI)000456070300052 ()2-s2.0-85056988962 (Scopus ID)
Note

QC 20190313

Available from: 2019-03-13 Created: 2019-03-13 Last updated: 2019-03-13Bibliographically approved
Ersson, M. (2019). Colocated pressure-velocity coupling in finite difference methods. Progress in Computational Fluid Dynamics, An International Journal, 19(5), 273-281
Open this publication in new window or tab >>Colocated pressure-velocity coupling in finite difference methods
2019 (English)In: Progress in Computational Fluid Dynamics, An International Journal, ISSN 1468-4349, E-ISSN 1741-5233, Vol. 19, no 5, p. 273-281Article in journal (Refereed) Published
Abstract [en]

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 compact. This is obtained by discretising the continuity and pressure derivatives with first order differences with opposite directions, i.e., backward difference for continuity and forward difference for pressure (BCFP). The equations are also approximated using a forward difference for continuity and a backward difference for pressure (FCBP). In order to obtain a second order approximation the mean between BCFP and FCBP is used, i.e., a central difference. The paper gives a useful alternative to existing methods for pressure-velocity coupling in finite difference methods in which a staggered arrangement is not desirable.

Place, publisher, year, edition, pages
INDERSCIENCE ENTERPRISES LTD, 2019
Keywords
finite difference method, FDM, spurious oscillations, colocated variable arrangement, collocated variable arrangement
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-261052 (URN)10.1504/PCFD.2019.102037 (DOI)000484580300001 ()2-s2.0-85072014829 (Scopus ID)
Note

QC 20191001

Available from: 2019-10-01 Created: 2019-10-01 Last updated: 2019-10-01Bibliographically approved
Liu, Y., Ersson, M., Liu, H., Jönsson, P. & Gan, Y. (2019). Comparison of Euler-Euler Approach and Euler–Lagrange Approach to Model Gas Injection in a Ladle. Steel Research International, 90(5), Article ID 1800494.
Open this publication in new window or tab >>Comparison of Euler-Euler Approach and Euler–Lagrange Approach to Model Gas Injection in a Ladle
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2019 (English)In: Steel Research International, ISSN 1611-3683, E-ISSN 1869-344X, Vol. 90, no 5, article id 1800494Article in journal (Refereed) Published
Abstract [en]

The gas injection in a ladle using a porous plug is simulated using both the Euler-Euler and Euler-Lagrange approaches. The effects of various forces, bubble sizes, and bubble injection frequencies on the flow pattern are modeled. For predicting axial velocity and turbulent kinetic energy, the Euler-Lagrange approach fits better than Euler-Euler approach with the measured data. In the Euler-Euler approach, differences in axial velocities and turbulent kinetic energies for various bubble sizes mainly appears in the plume zone. In the Euler-Lagrange approach, different bubble sizes with the same injection frequency have a small impact on the turbulence dissipation. Furthermore, the turbulent dispersion from the gas phase to the liquid phase has an important effect on the plume structure and spout eye formation. For both modeling, the smaller the bubble diameter is, the larger the axial velocity and turbulent kinetic dissipation are in the central zone. For the bubble coalescence and breakup, according to the comparison of two modeling approaches, the Euler-Lagrange approach is more accurate in predicting the flow pattern for gas injection with a porous plug in the ladle.

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2019
Keywords
bubble coalescence and breakup, ladle, mathematical modeling, porous plug, Coalescence, Computational fluid dynamics, Flow patterns, Kinetics, Ladles, Lagrange multipliers, Mathematical models, Turbulent flow, Bubble coalescence, Euler-Euler approach, Injection frequencies, Lagrange approach, Turbulence dissipation, Turbulent dispersion, Turbulent kinetic energy, Kinetic energy
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-252488 (URN)10.1002/srin.201800494 (DOI)000477083800005 ()2-s2.0-85062368543 (Scopus ID)
Note

QC 20190712

Available from: 2019-07-12 Created: 2019-07-12 Last updated: 2019-09-17Bibliographically approved
Bai, H., Ni, P., Ersson, M., Zhang, T. & Jönsson, P. (2019). Effect of swirling flow tundish submerged entry nozzle outlet design on multiphase flow and heat transfer in mould. Ironmaking & steelmaking
Open this publication in new window or tab >>Effect of swirling flow tundish submerged entry nozzle outlet design on multiphase flow and heat transfer in mould
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2019 (English)In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812Article in journal (Refereed) Published
Abstract [en]

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 effect to decrease the horizontal velocity of liquid steel flowing out the SEN outlet, reducing the steel flow velocity towards the solidification front. Although a higher velocity was found near the slag/steel interface with the enlarged outlet SEN, but the turbulent kinetic energy was lower. The reason was that less circulation flows were formed in the region of the mould top. The weak horizontal flow towards the solidification front with the enlarged outlet SEN induced lower wall shear stresses, at the same time it also formed a lower temperature distribution near the solidified shell.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2019
Keywords
Swirling flow tundish, SEN outlet design, multiphase flow, heat transfer, continuous casting mould, steel, numerical simulation, steel, slag behavior
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-255180 (URN)10.1080/03019233.2019.1630215 (DOI)000472437100001 ()2-s2.0-85068138836 (Scopus ID)
Note

QC 20190904

Available from: 2019-09-04 Created: 2019-09-04 Last updated: 2019-09-04Bibliographically approved
Bölke, K., Ersson, M., Andersson, N. A. I., Imris, M. & Jönsson, P. (2019). Experimental Determinations of Mixing Times in the IronArc Pilot Plant Process. METALS, 9(1), Article ID 101.
Open this publication in new window or tab >>Experimental Determinations of Mixing Times in the IronArc Pilot Plant Process
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2019 (English)In: METALS, ISSN 2075-4701, Vol. 9, no 1, article id 101Article in journal (Refereed) Published
Abstract [en]

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 measuring the mixing time in the slag bath. Moreover, slag investigations were done both based on light optical microscope studies as well as by Thermo-Calc calculations in order to determine the phases of the slag during operation. This was done because the viscosity (which is another important parameter) is dependent on the liquid and solid fractions of the slag. The overall results show that it was possible to determine the mixing time by means of the addition of a tracer (MnO2 powder) to the slag. The mixing time for the trials showed that the slag was homogenized after seconds. For two of the trials, homogenization had already been reached in the second sample after tracer addition, which means <= 8 s. The phase analysis from the slag indicated that the slag is in a liquid state during the operation of the process.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
IronArc process, Ironmaking, pig iron production, mixing time, CO2 reduction, slag investigation
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-246292 (URN)10.3390/met9010101 (DOI)000459738500100 ()2-s2.0-85060686372 (Scopus ID)
Note

QC 20190325

Available from: 2019-03-25 Created: 2019-03-25 Last updated: 2019-05-13Bibliographically approved
Arzpeyma, N., Ersson, M. & Jönsson, P. (2019). Mathematical Modeling of Postcombustion in an Electric Arc Furnace (EAF). METALS, 9(5), Article ID 547.
Open this publication in new window or tab >>Mathematical Modeling of Postcombustion in an Electric Arc Furnace (EAF)
2019 (English)In: METALS, ISSN 2075-4701, Vol. 9, no 5, article id 547Article in journal (Refereed) Published
Abstract [en]

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 results show a CO flow rate of 0.6 kgs(-1) and 0.8 kgs(-1) for operation modes of burner and burner + lancing. Increase of the secondary oxygen flow rates of 60% and 70% result in 17% and 7% increase in the postcombustion ratio (PCR) for the burner and burner lancing modes, respectively.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
EAF, postcombustion, CFD
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-257587 (URN)10.3390/met9050547 (DOI)000478818700065 ()2-s2.0-85066731085 (Scopus ID)
Note

QC 20190920

Available from: 2019-09-20 Created: 2019-09-20 Last updated: 2019-09-20Bibliographically approved
Yin, J., Ersson, M., Mao, H. & Jönsson, P. G. (2019). Mathematical Modelling of the Initial Mold Filling with Utilization of an Angled Runner. Metals, 9(6)
Open this publication in new window or tab >>Mathematical Modelling of the Initial Mold Filling with Utilization of an Angled Runner
2019 (English)In: Metals, ISSN 2075-4701, Vol. 9, no 6Article in journal (Refereed) Published
Abstract [en]

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 fluid flow characteristics. Moreover, a mathematical model with a horizontal runner was applied as a reference. The predictions indicate that the angled-runner-design decreases the hump height during the initial filling stage, which results in less entrapment of mold flux into the mold. Nevertheless, increasing the angle of runner can result in a lower hump height, while the 30 degree angled runner gives a much more stable increase of the hump height during the initial filling stage. Besides CFD calculations, some thermodynamic calculations are taken into account for the chemical reactions between liquid steel and gas. The results show that the bubble shrinks due to the fact that N and O are dissolved into steel. The present findings strongly suggest that changing the horizontal runner to an angled runner would be an effective means of reducing flow unevenness during the initial filling of ingots, if the added steel losses are deemed acceptable.

Place, publisher, year, edition, pages
MDPI, 2019
Keywords
CFD, bubble, uphill teeming, ingot casting, mathematical modelling, gating system, thermodynamic calculations
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-255577 (URN)10.3390/met9060693 (DOI)000475356500077 ()2-s2.0-85070457970 (Scopus ID)
Note

QC 20190802

Available from: 2019-08-02 Created: 2019-08-02 Last updated: 2019-10-04Bibliographically approved
Khodabandeh, E., Akbari, O. A., Toghraie, D., Saffari Pour, M., Jönsson, P. & Ersson, M. (2019). Numerical investigation of thermal performance augmentation of nanofluid flow in microchannel heat sinks by using of novel nozzle structure: sinusoidal cavities and rectangular ribs. Journal of the Brazilian Society of Mechanical Sciences and Engineering, 41(10), Article ID UNSP 443.
Open this publication in new window or tab >>Numerical investigation of thermal performance augmentation of nanofluid flow in microchannel heat sinks by using of novel nozzle structure: sinusoidal cavities and rectangular ribs
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2019 (English)In: Journal of the Brazilian Society of Mechanical Sciences and Engineering, ISSN 1678-5878, E-ISSN 1806-3691, Vol. 41, no 10, article id UNSP 443Article in journal (Refereed) Published
Abstract [en]

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 study show that Nusselt number is dependent on nanoparticles concentration, inlet geometry and Reynolds number. As the nanofluid concentration increases from 0 to 0.1% and Reynolds number from 50 to 1000, the Nusselt number enhances nearly up to 3% for increase in fluid concentration and averagely from 15.45 to 54.1 and from 14.5 to 55.9 for geometry with and without rectangular rib, respectively. The presence of ribs in the middle section of microchannel and curves close to hot walls causes a complete mixing of the fluid in different zones. When the nanoparticles concentration is increased, the pressure drop and velocity gradient will become higher. An increased concentration of nanoparticles in contribution with higher Reynolds numbers only increases the fraction factor slightly. (The fraction factor increases nearly 37% and 35% for Re = 50 and 1000, respectively.) The highest uniform temperature distribution can be found in the first zones of fluid in the microchannel and by further movement of fluid toward exit section, because of decreasing difference between surface and fluid temperature, the growth of temperature boundary layer increases and results in non-uniformity in temperature distribution in microchannel and cooling fluid. With decrease in the concentration from 0 to 0.1%, the average outlet temperature and FOM decrease nearby 0.62% and 6.15, respectively.

Place, publisher, year, edition, pages
SPRINGER HEIDELBERG, 2019
Keywords
Thermal performance, Nanofluid flow, Microchannel heat sinks, Novel nozzle structure, Sinusoidal cavities, Rectangular ribs
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-261943 (URN)10.1007/s40430-019-1952-z (DOI)000487122000004 ()
Note

QC 20191015

Available from: 2019-10-15 Created: 2019-10-15 Last updated: 2019-10-15Bibliographically approved
Bai, H., Ersson, M. & Jönsson, P. (2019). Numerical study of an application of a divergent reverse TurboSwirl nozzle in the billet continuous casting process. Ironmaking & steelmaking, 46(2), 148-158
Open this publication in new window or tab >>Numerical study of an application of a divergent reverse TurboSwirl nozzle in the billet continuous casting process
2019 (English)In: Ironmaking & steelmaking, ISSN 0301-9233, E-ISSN 1743-2812, Vol. 46, no 2, p. 148-158Article in journal (Refereed) Published
Abstract [en]

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 to the straight nozzle. A stronger swirling flow can be obtained at the SEN outlet, which leads to a calmer flow field and an appropriately active meniscus flow that could improve the heat and mass transfer near the meniscus. The swirl number in the SEN is independent of the casting speed, while a lower casting speed yields a lower maximum wall shear stress. The DRTSN is connected to the tundish by an elbow and a horizontal runner. A longer horizontal runner supplies a more uniform velocity profile and a more symmetrical flow pattern.

Place, publisher, year, edition, pages
TAYLOR & FRANCIS LTD, 2019
Keywords
Swirling flow, TurboSwirl, divergent nozzle, SEN, billet continuous casting
National Category
Fluid Mechanics and Acoustics
Identifiers
urn:nbn:se:kth:diva-244514 (URN)10.1080/03019233.2017.1360433 (DOI)000458159900006 ()2-s2.0-85027106950 (Scopus ID)
Note

QC 20190402

Available from: 2019-04-02 Created: 2019-04-02 Last updated: 2019-04-02Bibliographically approved
Ni, P., Ersson, M., Jonsson, L. T. & Jönsson, P. (2018). A study on the nonmetallic inclusion motions in a swirling flow submerged entry nozzle in a new cylindrical tundish design. Metallurgical and materials transactions. B, process metallurgy and materials processing science, 49(2), 723-736
Open this publication in new window or tab >>A study on the nonmetallic inclusion motions in a swirling flow submerged entry nozzle in a new cylindrical tundish design
2018 (English)In: Metallurgical and materials transactions. B, process metallurgy and materials processing science, ISSN 1073-5615, E-ISSN 1543-1916, Vol. 49, no 2, p. 723-736Article in journal (Refereed) Published
Abstract [en]

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 steel flow exists in this region. This high rotational flow of 0.7 m/s provides the required momentum for the formation of a strong swirling flow inside the SEN. The results show that inclusions larger than 40 µm were found to deposit to a smaller extent on the SEN wall compared to smaller inclusions. The reason is that these large inclusions have Separation number values larger than 1. Thus, the swirling flow causes these large size inclusions to move toward the SEN center. For the nonspherical inclusions, large size inclusions were found to be deposited on the SEN wall to a larger extent, compared to spherical inclusions. More specifically, the difference of the deposited inclusion number is around 27 pct. Overall, it was found that the swirling flow contains three regions, namely, the isotropic core region, the anisotropic turbulence region and the near-wall region. Therefore, anisotropic turbulent fluctuations should be taken into account when the inclusion motion was tracked in this complex flow. In addition, many inclusions were found to deposit at the SEN inlet region. The plotted velocity distribution shows that the inlet flow is very chaotic. A high turbulent kinetic energy value of around 0.08 m2/s2 exists in this region, and a recirculating flow was also found here. These flow characteristics are harmful since they increase the inclusion transport toward the wall. Therefore, a new design of the SEN inlet should be developed in the future, with the aim to modify the inlet flow so that the inclusion deposition is reduced.

Place, publisher, year, edition, pages
Springer, 2018
National Category
Metallurgy and Metallic Materials
Identifiers
urn:nbn:se:kth:diva-238356 (URN)10.1007/s11663-017-1162-y (DOI)000426808500024 ()2-s2.0-85047456102 (Scopus ID)
Note

QC 20181113

Available from: 2018-11-12 Created: 2018-11-12 Last updated: 2018-11-12Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0003-4384-7984

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