| 1. |
- Grip, Carl-Erik, et al.
(författare)
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Theoretical and practical study of thermal stratification and drainage in ladles of different geometry
- 2000
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Ingår i: Scandinavian journal of metallurgy. - : Wiley. - 0371-0459 .- 1600-0692. ; 29:1, s. 30-38
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Tidskriftsartikel (refereegranskat)abstract
- SSAB Lulea, SSAB Oxelosund, MEFOS and Lulea University of Technology have cooperated in developing theoretical models for prediction of thermal stratification and drainage in steel ladles. Predicted results have been verified by measurements done in production ladles with heat weighs of 105 and 200 tonne as well as in a 7-tonne pilot plant ladle. The thermal stratification was measured by thermocouples at different depths. The drainage flow was studied by means of tracer experiments. Numerical simulation models of the steel flow were developed for 7, 105 and 200 tonne steel ladles. The agreement between predictions and measurements was found to be good. The conclusion is that CFD simulation gives a good prediction of stratification and drainage flows in production ladles.
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| 2. |
- Grip, Carl Erik, et al.
(författare)
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Numerical prediction and experimental verification of thermal stratification during holding in pilot plant and production ladles
- 1999
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 39:7, s. 715-721
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Tidskriftsartikel (refereegranskat)abstract
- A 3-dimensional CFD-model has been developed to simulate the natural convection flow in ladles. Qualified measurements of temperature and velocities in 107 and 7 tonne ladles have been made to verify the model. The downward convection flow at the ladle wall has been studied using radioactive isotopes and the thermal stratification has been studied by means of continuous temperature measurements. The experimental techniques are complex and additional numerical simulations have been carried out to study the effect of the measurement technique on the measurement error. The result indicates that the measurements are of sufficient accuracy for the validation. The measurements are compared to predictions from the numerical model. The main conclusion is that the theoretical CFD model gives a very accurate estimation of the temperature distribution during holding.
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| 3. |
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| 4. |
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| 5. |
- Saffari Pour, Mohsen, 1987-, et al.
(författare)
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The behavior of impurities during producer gas implementation as alternative fuel in steel reheating furnaces : A CFD and thermochemical study
- 2016
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Ingår i: ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE). - USA : American Society of Mechanical Engineers (ASME). - 9780791850589
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Konferensbidrag (refereegranskat)abstract
- 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 for the quality of final steel products. The quality of steel can be highly affected by the interaction of impurities with iron-oxides at hot slab surfaces. In this research, the combustion of producer gases and the behavior of impurities at the steel slab surface are studied by aid of a novel coupled computational fluid dynamics (CFD) and thermodynamics approach. The impurities are introduced as mineral ash particles with the particle size distributions of 15-100 νm. The CFD predicted data regarding the accumulation of ash particles are extracted from an interface layer at the flaring gas media around the steel slab surface. Later on, these predicted data are used for the thermo-chemical calculations regarding the formation of sticky solutions and stable phases at the steel slab surface. The results show that the particles are more likely follow the flow due to the high injection velocity of fuel (70 m/s) and the dominant inertial forces. More than 90 percent of particles have been evacuated through the exhaust pipes. The only 10 percent of remaining particles due to the high recirculation zones at the middle of furnace and the impinging effect of front walls tend to stick to the side wall of slab in the heating zone more than the soaking zone.
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| 6. |
- Alexis, Jonas, et al.
(författare)
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Heating and electromagnetic stirring in a ladle furnace – a simulationmodel
- 2000
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Ingår i: ISIJ International. - : Iron and Steel Institute of Japan. - 0915-1559 .- 1347-5460. ; 40:11, s. 1098-1104
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Tidskriftsartikel (refereegranskat)abstract
- A three-dimensional simulation model coupling heating and induction stirring in an ASEA-SKF ladle furnace was developed. Data of the heat transfer from the area to the steel bath were predicted in a separate model and included as boundary conditions in a ladle model. The are model considers the contributions of heat transferred by of each of the following mechanisms: radiation, convection, condensation and energy transported by electrons. Predictions were made to simulate the change of temperature distribution in the ladle during simultaneous heating with electrodes and stirring by induction. A first attempt was made to compare the predictions with measured temperatures from a 100 t ASEA-SKF ladle. The agreement was found to be fairly good when heat-flux data for a 25 cm are length were used as input to the ladle model. This indicates that the model can be used for more in-depth studies of the effects of heating for ladles that are inductively stirred.
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| 7. |
- Andersson, Margareta A.T., et al.
(författare)
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Slag-metal reactions during ladle treatment with focus on desulphurisation
- 2002
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Ingår i: Ironmaking & steelmaking. - : Informa UK Limited. - 0301-9233 .- 1743-2812. ; 29:3, s. 224-232
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Tidskriftsartikel (refereegranskat)abstract
- Within several cooperative projects, KTH (Royal Institute of Technology), Ovako Steel AB, and MEFOS have investigated the desulphurisation of bearing steel during vacuum degassing. The work includes thermodynamic calculations of the slag-metal equilibrium, CFD modelling of slag-metal reactions, and plant trials. Results from the various studies are presented and discussed in this paper. Models for predicting slag properties (sulphide capacity, viscosity, and oxide activities) in liquid slags as functions of slag composition and temperature have been used for the calculation of data which have been employed in static and dynamic modelling of sulphur refining. The results from static modelling show that the method allows fast and easy evaluation of the theoretical desulphurisation conditions during degassing at Ovako Steel AB, as well as theoretical determination of the parameters that have the greatest influence on the equilibrium sulphur distribution. The conclusion from dynamic modelling is that the vacuum degassing operation can be described dynamically with the present knowledge of sulphide capacity, sulphur distribution, viscosity, and oxide activities of ladle slags if this knowledge is combined with fluid flow modelling to derive the overall kinetics. The presented model approaches have been found useful in understanding the sulphur refining process at Ovako Steel AB. The dynamic modelling concept is also believed to have potential for dynamic descriptions of other slag-metal reactions in steelmaking.
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| 8. |
- Jönsson, Pär, et al.
(författare)
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Focus on clean steel within Jernkontoret's Research - an overview
- 2008
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Ingår i: Revue de métallurgie (Imprimé). - : EDP Sciences. - 0035-1563 .- 1156-3141. ; 105:6, s. 317-326, s. 317-326+III
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Tidskriftsartikel (refereegranskat)abstract
- Some highlights from the Jernkontoret Research with focus on the modeling work of the lost decade are presented. First the concept of a fundamental mathematical model is discussed. Thereafter, a short review of growth and separation models based on fundamental modeling of ladles is presented. Then, recent modeling efforts within Jernkontoret's Research are highlighted.
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| 9. |
- Liu, Hailong, et al.
(författare)
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A study of influencing factors on the particle concentration and deposition in a model room with a coupled drift flux and Eulerian deposition model
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The drift flux model coupled with a unified Eulerian deposition model is presented and used to discuss how it is possible to improve the understanding of the particle transport behavior in indoor environments. The validation of the model itself is achieved by a good agreement with published experimental data. A series of simulation cases have been conducted to illustrate the influential factors (particle size and density, wall roughness, release location and duration, flow obstacle) for particle concentration-distributions and depositions. The results show that the uniformity of the concentration distribution decreases as the particle size increases from submicron (0.01 and 0.1 µm) to micron (1 -10 µm), as well as when the particle density increases from 700 to 5600 kg/m3. Also, the well-mixed assumptions seem adequate for particles with a diameter smaller than 2 µm for the studied cases. Two parameters, namely, the deposited amount and deposition fraction are introduced to illustrate the deposition effect on micro sized particles. The results indicate that the deposition effect become more predominant for particles with a diameter greater than 2 µm. In view of the particle deposition, sub-micron particles are more sensitive to the variation of surface materials (wall roughness) than micron particles. For an internal source in the room, where a release over a long duration is considered, the particle dispersion is strongly related to the release location. However, this is not the case for a short release time. By studying a simple case consisting of a room with a table, it is obvious that obstacles or furnished settings bring a complicated situation for the particle dispersion and deposition. Therefore, specific simulations are needed for each real indoor environment.
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| 10. |
- Safavi Nick, Reza, et al.
(författare)
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A mathematical model of the solid flow behavior in a real dimension blast furnace : Effects of the solid volume fraction on the velocity profile
- 2013
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Ingår i: Steel Research International. - : Wiley. - 1611-3683 .- 1869-344X. ; 84:10, s. 999-1010
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Tidskriftsartikel (refereegranskat)abstract
- A mathematical model based on the continuum mechanic concept has been developed to describe the profile of solid particles in a blast furnace with respect to the in-furnace conditions and characteristics, e.g., the shape and size of the deadman. The Navier-Stokes differential equation for multi-phase multi-dimensional space has been used to describe the behavior of existing phases. The equation has been modified to make it possible to describe the dual nature of the solid phase in the system by applying the concept of the solid surface stress to characterize the inter-granular surface interactions between particles. Since different phases co-exist in a blast furnace, the volume fraction plays an important role in a blast furnace. Therefore, the influence of three different packing densities (0.68, 0.71, and 0.74, respectively) on the profile of the flow in the upper part of a furnace down to the tuyeres level has been studied. It is shown that an increase in the volume fraction of the solid phase lead to a decrease in magnitude of the velocity. The decrease in the magnitude of the velocity due to an increase in the solid volume fraction will increase the resident time of the particles inside a blast furnace. In addition, it is shown that the solid phase velocity magnitude decreases from the throat to the belly of the furnace for the studied conditions. However, after belly the velocity magnitude increases.
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